ZoningZoningZoningZoningZoning

Design GuideDesign GuideDesign GuideDesign GuideDesign Guide

Zone

Zone

8500 NW River Park Drive · Parkville , MO 64152Toll Free Phone: 866-918-1100

PH: (816) 505-1100 · FAX: (816) 505-1101 · E-mail: mail@wattmaster.comVisit our web site at www.orioncontrols.com

Form: OR-SYS-ZDG-01B Copyright 2002 WattMaster Controls, Inc.AAON is a registered trademark of AAON, Inc., Tulsa, OK.

WattMaster Controls, Inc. assumes no responsibility for errors, or omissions.This document is subject to change without notice.

This manual is intended as a general guide and reference for the correct application of Orion zoning systems.It is not intended to be a substitute for careful HVAC system engineering design and layout. WattMasterassumes no responsibility for incorrect or poor system application or design implemented by any ofWattMaster’s representatives or their respective customers.

Zoning Systems Versus True VAV Systems .......................................................................... 5

How Orion Works .................................................................................................................. 6

Why Should I Use Orion?...................................................................................................... 8

What Is Unique About Orion? .......................................................................................... 8-10

Basics Of Designing A Zoning System................................................................................ 11

Design Considerations ................................................................................................... 12-13

Zoning Design Procedures ............................................................................................. 14-23

System Installation ......................................................................................................... 24-27

Application Notes ................................................................................................................ 29

Appendix ........................................................................................................................ 30-31

Table Of Contents

Figure 1-1: Typical Orion Zoning System Overview ............................................................ 7

Figure 1-2: Zones Affected By Outdoor Load.................................................................. .14

Figure 1-3: Zone Layout With External Zones Only ......................................................... .15

Figure 1-4: Zones With North And South Exposures ....................................................... .15

Figure 1-5: Zoning And Constant Volume Units ............................................................... .15

Figure 1-6: Round Bypass Damper .................................................................................. .17

Figure 1-7: Rectangular Bypass Damper & Kit ................................................................ .17

Figure 1-8 Preferred Sensor Location .............................................................................. 18

Figure 1-9: Acceptable Sensor Location ........................................................................... 18

Figure 1-10: Least Desirable Sensor Location .................................................................... 18

Figure 1-11: Pressure Dependent Damper ......................................................................... 19

Figure 1-12: Pressure Independent Damper ....................................................................... 19

Figure 1-13: Rectangular Damper & Damper Kit ................................................................ 21

Figure 1-14: WattMaster Communication Wire ................................................................... 25

Figure 1-15: Networked System Communications Loop Wiring .......................................... 28

Figure 1-16: Transformer & Wire Sizing Considerations Without Modular Connectors ...... 30

Figure 1-17: Transformer & Wire Sizing Considerations With Modular Connectors ........... 31

Table Of Figures & Tables

Orion Systems 5

Zoning Design Guide

GeneralEven though there are some similarities between zonecontrol systems and Variable Air Volume (VAV) sys-tems, there are some major differences. In many casessystems will be called VAV when in fact they are reallya zoning system or are referred to as a zoning systemwhen they are really a VAV system. Always make surethat you do not try to adapt a zoning system to a VAVdesign system. Understanding the differences will helpyou to prevent misapplication of the Orion zoning sys-tem. In the paragraphs that follow we will try to ex-plain the differences, advantages and disadvantages ofeach and explain their operation.

VAV SystemsThese systems consist of an HVAC unit that is gener-ally a cooling only unit and VAV terminal units locatedin the downstream ductwork that are used to controlthe amount of constant temperature air delivered to thevarious building zones. Sometimes the HVAC unit mayhave gas or electric heat, but it is typically sized andapplied for morning warm-up purposes. The HVAC unitis designed to vary the volume of air that is supplied tothe duct system by using either inlet vanes or an elec-tronic variable frequency drive. These devices modu-late to control the air flow through the supply fan inresponse to the static pressure in the duct system. VAVsystems typically use high velocity VAV terminal unitsto distribute the air to the zones. As the various VAVterminal units in the different zones open and close tosupply the constant temperature air to the spaces, theHVAC unit varies the volume of constant temperatureair based on the static pressure in the ductwork. TheHVAC unit is designed to maintain a constant cold sup-ply air temperature regardless of the air flow volume inthe system. The HVAC unit cycles it’s cooling stagesto maintain a constant predetermined supply air tem-perature. It typically runs continuously based on a sched-ule.

For perimeter zones requiring heat, reheat coils (elec-tric or hot water) located in the terminal units are usedto supply heated air to the space. Many times fan pow-ered terminal boxes are used and most of them incor-porate electric or hot water heating coils to provide pe-rimeter zone heating. In summary a true VAV systemuses a variable volume fan supplying constant tempera-ture air to the system with variable volume terminalunits used to control the volume of constant tempera-ture air delivered to the space. Generally these systemsuse pressure independent damper control.

Zoning Systems Versus True VAV Systems

Orion Zoning SystemsThe Orion zoning system is quite different in operationand design from the VAV system previously discussed.Air volume control of the zoning system can either beachieved by utilizing a VFD drive to modulate the unitfan speed or achieved by bypassing air from the HVACunit supply duct back into the HVAC unit return airduct on the unit inlet. The supply fan VFD or the by-pass air damper is controlled and modulated based onthe static pressure value sensed by a static pressure sen-sor located in the supply air duct downstream of theunit supply air discharge. The supply fan VFD modu-lates the fan speed or the bypass damper modulates openand closed based on the static pressure in the duct. Thetemperature at the HVAC unit discharge varies in rela-tion to the demand from the zones.

HVAC units used for the zoning system will typicallyhave both heating and cooling capabilities. The unit sup-plies a variable volume of cold or hot air to the ductsystem which is fed to the individual zones by modu-lating zone dampers. Each zone controller relays its heat-ing or cooling demand to the Polling Device installedon it’s local communications loop. The Polling Devicedetermines the HVAC unit mode of operation (heating,cooling or vent mode) depending on the demand fromthe zone controllers and relays this to the HVAC unitcontroller. The Polling Device utilizes a voting systemto determine the correct mode of operation. Each zonecontroller determines (based on its heating and coolingsetpoints) whether or not to use the air being suppliedby the HVAC unit. For example, one of the zones iscalling for cooling when the temperature in the duct isabove the zones cooling setpoint. This zone will moveto its minimum cooling position to prevent warm airbeing introduced into the space. With the zoning sys-tem the zone dampers are generally pressure dependent.Pressure independent operation is available but is notvery common. Reheat and/or fan powered terminal unitscan be used but aren’t commonly part of the typicalzoning system.

ConclusionTypically a VAV, HVAC unit and associated controls ismore expensive than a CAV (Constant Volume) unitutilizing zoning system control, especially on smallerHVAC units. Many times the system can be redesignedto a zoning system with a significant cost savings andequal or better performance and comfort than a VAVsystem would provide. Orion Systems allow you theoption of which one is best for your application. Or ifdesired, VAV and zoned HVAC systems can also bemixed and matched on the same control system.

6 Orion Systems

Zoning Design Guide

How Orion Works

As previously discussed, in contrast to the VAV systemthe zoning system supplies variable temperature air tothe supply ductwork. The zone dampers modulate andsupply the correct amount of conditioned air to the build-ing zones and the zone dampers The Polling Devicecalculates the heating and cooling requirements for eachzone based on real time information received from eachZone Controller/Damper. The Polling Device then di-rects the HVAC unit to provide the appropriate amountof heating, cooling, and ventilation to satisfy each zone’srequirements. A static air pressure sensor is used to al-low the controller to modulate a bypass damper or aVFD (variable frequency drive) to maintain constantduct pressure.

The Orion system uses a unique 3 tier approach to con-trolling the system:

• Voting Zones

• System Demand

• Priority

This 3 tier system works in an integrated fashion tomaintain proper control of the equipment and effectivecontrol of comfort in the zone.

First the zone must initiate a vote to the HVAC unit.This occurs when a zone becomes more than 1 degreeoff setpoint. At this time a vote is placed for heating orcooling. Next the Polling Device evaluates the total cool-ing demand or heating demand of the zones served bythe HVAC unit, to determine which requirement is morecritical. Finally, the system looks for any priority con-ditions, which would take precedence over other zones.All three of these elements working together provideaccurate and stable control of comfort.

Additional control features are taken into account toprovide very effective control of the system. Some ofthese include priority override, supply air temperaturelimits, outside air temperature lockouts, and minimum/maximum position control over the zone dampers.

Substantial savings can be realized using the Orion Zon-ing system instead of having to install multiple rooftopunits to accommodate multiple zone requirements. TheOrion Zoning system is versatile and can be used withany packaged roof top unit or split system. It controls avariety of terminal unit functions including single ductpressure dependent, pressure independent, series fan ,parallel fan terminals and electric or hot water reheat.

Orion Systems 7

Zoning Design Guide

Fig

ure

1-1:

Typ

ical

Ori

on Z

onin

g Sy

stem

Ove

rvie

w

AC

TU

AT

OR

EX

PA

NS

ION

NET

ADD

8

3216

24

1

SW1

U1

EE

PR

OM

EP

RO

M

PJ4

AIR

FLO

WS

PA

CE

SE

NS

OR

PJ3

U7

TB2

AIN

GND

AUX

T

SH

LD

R

TB

1

OUT IN

P1

P2

K1

K2

PJ2

PJ1

JP1

VAVZ CONTROLLERPYS101854 REV.

AC

TU

AT

OR

EX

PA

NS

ION

NET

ADD

8

3216

24

1

SW1

U1

EE

PR

OM

EP

RO

M

PJ4

AIR

FLO

WS

PA

CE

SE

NS

OR

PJ3

U7

TB2

AIN

GND

AUX

T

SH

LD

R

TB

1

OUT IN

P1

P2

K1

K2

PJ2

PJ1

JP1

VAVZ CONTROLLERPYS101854 REV.

Heating

Cooling

Filter

Mo

du

lar

Ro

om

Se

ns

or

Mo

du

lar

Ro

om

Se

ns

or

Zo

ne

Co

ntr

oller

Mo

du

lar

Syste

mM

an

ag

er

Po

we

r/C

om

mB

oa

rdO

nL

oo

p1

Min

iLin

kIn

terf

ace

Fo

rL

oo

p1

Mo

du

lar

Ca

ble

sTo

Oth

er

Zo

ne

Co

ntr

oll

ers

On

Lo

op

1M

od

ula

rC

ab

les

To

Oth

er

Zo

ne

Co

ntr

oll

ers

On

Lo

op

1

Min

iLin

kIn

terf

ac

eF

or

Lo

op

2

Ne

two

rkL

oo

pTo

Min

iLin

kO

nL

oo

p3

Of

Sy

ste

m

Lo

ca

lL

oo

pTo

VA

V/C

AV

Co

ntr

oll

er

An

dP

ow

er/

Co

mm

Bo

ard

On

Lo

op

2o

fS

ys

tem

Zo

ne

Co

ntr

oller

Mo

du

lar

Po

llin

gD

ev

ice

Lo

op

1

Zo

ne

Da

mp

er

&A

ctu

ato

r

Zo

ne

Da

mp

er

&A

ctu

ato

r

By

pa

ss

Da

mp

er

&A

ctu

ato

r

Ou

tsid

eA

ir

Ou

tsid

eA

irTem

pS

en

so

r

Retu

rnA

irTem

pS

en

so

r

Su

pp

lyA

irTe

mp

Se

ns

or

Mo

du

lar

Serv

ice

To

ol

Ro

oft

op

HV

AC

Un

it

VA

V/C

AV

Co

ntr

oll

er

On

Lo

op

1

Retu

rnA

irR

etu

rnA

irD

uc

t

Ex

ha

us

tA

ir

Sta

tic

Pre

ss

ure

Se

ns

or

&P

ick

up

Tu

be

Su

pp

lyA

irD

uc

t

HI

LO

Co

mm

Lin

kIIC

om

pu

ter

(Optional)

W

C

LI

ATT

MASTE

R

ON

TRO

S,

NC

CO

MM

LIN

KII

L

C

M M

O

O

O

O

M

D

P

PE

Re

mo

teL

ink

(Optional)

Rem

ote

Lin

k

C

O

N

T

R

O

L

S

SIG

DET

RDY

SND

REC

PWR

EX

PA

NSIO

N

SEN

SO

R

PRESSU

RE

GN

D

7A

IN

AO

UT2

AO

UT1

AIN

GN

D

GN

D

5AIN

AIN

AIN 432

T'ST A

T

24

VA

C

NETW

ORK

16

TOKEN

32

84

GN

D

AIN 1

12

V

INPU

TS

RSH

LD

T

CO

MM

1 2

YS1

01

71

8

TUC

5R

PL U

S

COM1-3

R5

COM4-5

R4

R3

R2

R1

RN2

HIG

HS

PE

ED

LO

OP

R

INT

ER

FA

CE

YS

101697

T

U10

CX

4U

4RA

M

CX

3

U2

CX

2U

3EP

RO

M

R6

R5

WD

OG

U9

U8

R14

R15

R13

R12

TB

1

R

R10

LO

OP

R11

T

JO2

32

JP

1

U5

2 1684

U1

CX

11

R1

ADDR

JO1

J1

R3

R2

NE

TW

OR

K

TB

2

RT

RN2

HIG

HS

PE

ED

LO

OP

R

INT

ER

FA

CE

YS

101697

T

U10

CX

4U

4RA

M

CX

3

U2

CX

2U

3EP

RO

M

R6

R5

WD

OG

U9

U8

R14

R15

R13

R12

TB

1

R

R10

LO

OP

R11

T

JO2

32

JP

1

U5

2 1684

U1

CX

11

R1

ADDR

JO1

J1

R3

R2

NE

TW

OR

K

TB

2

RT

AL

AR

M

CO

MM

UN

IC

AT

IO

NS

WA

TT

MA

ST

ER

CO

NT

RO

LS

IN

C.

OA OR LM EE CW RR

OV

R

OA OR LM EE CW RR

OV

R

TB2

VAC

F1

25

4A

24

SHLD

T

R

POWER

LD1

TB1

C1

POWER & COMMDIST. BOARDYS101856REV. 0

P5

P4

P3

P1

D1

V1

R1

P2

CO

MM

PIN

PO

WE

R&

CO

MM

OU

T

EN

TER

CLE

AR

ES

C

PR

EV

NEXT

DO

WN

UP

65

4 DEC7

08

13

2

9

MIN

US -

ST A

TUS

SETP

OIN

TS

SC

HED

ULE

S

ALA

RM

S

OVER

RID

ES

Mode

Sele

cti

on

EN

TER

CLE

AR

ES

C

PR

EV

NEXT

DO

WN

UP

65

4 DEC7

08

13

2

9

MIN

US -

ST A

TUS

SETP

OIN

TS

SC

HED

ULE

S

CO

NFI

GU

RA

TIO

N

ALA

RM

S

ON

OVER

RID

ES

BA

LA

NC

E-

TES

T

No

te:

Eith

er

aM

od

ula

rS

yste

mM

an

ag

er ,

aM

od

ula

rS

erv

ice

To

olo

ra

Pe

rso

na

lC

om

pu

ter

Usin

gth

eP

rism

Co

mp

ute

rF

ron

tE

nd

So

ftw

are

isR

eq

uire

dfo

rP

rog

ram

min

ga

nd

Co

nfig

ura

tio

no

fth

eO

rio

nS

yste

m.

Th

ey

Ma

yA

lso

be

Use

din

Co

mb

ina

tio

nw

ith

Ea

ch

Oth

er .

8 Orion Systems

Zoning Design Guide

Why Should I Use Orion?

Orion system was designed using proven technologywith a long history of successful installations. Our sys-tems have been refined over the years with the help offeedback from people in the field who work and livewith these systems on a daily basis. Our success isgreatly due to the fact that we have implemented changes

and enhancements based on real world experience notfrom tinkering with equipment in an isolated lab envi-ronment. This real world approach provides engineers,contractors, and end users with a control system that isefficient, reliable, and most importantly, keeps the cus-tomers comfortable!

What Is Unique About Orion?

Orion is unique because it has many features not foundon other systems. These features include

Integration with Existing EquipmentThe Orion HVAC unit controller is usually factory in-stalled by AAON. However, if you have a job withnew AAON equipment being installed and you wouldlike to tie in existing AAON or other manufacturersHVAC equipment to the system, the Orion controllersare designed to work with any manufacturers HVACequipment that will accept a standard thermostat con-nection. Another value added feature is that the Orioncontrollers include very comprehensive documentation,which was written in a format specifically for a “non-controls technician”. All setup and configuration pro-cedures are simple and easy to implement.

Pre-Engineered SoftwareSystem design, software, and documentation has alreadybeen done for you. This eliminates the costly expenseusually associated with conventional DDC systems,making the Orion system more competitive and easierto install and operate.

One Controller for VAV, Zoned or SingleZone CAV SystemsThe VAV/CAV unit controller can be field configuredfor VAV, zoning or constant volume applications.Notonly does Orion provide a networked zone control sys-tem for one or multiple VAV or zoned HVAC units, youcan also connect individual CAV (constant volume)single zone units the system eliminating the need touse programmable thermostats. Add-on devices areavailable which can control lighting, exaust fans, boil-ers and other building equipment on the same controlssystem.

User Friendly Set UpSince the Orion comes with menu driven, fill in theblank programming, system setup is simple. The sys-tem manual takes you step by step through the set upprocess. Default parameter values are programmed intopermanent memory so the system can be operational atstart-up. Specialized training is not required.

Orion Systems 9

Zoning Design Guide

True Network CommunicationsThe Orion uses a three wire, RS-485 loop for commu-nication between all controllers in the system. This pro-vides a very reliable form of communication with flex-ibility of installation. The loop can be wired in a “daisychain” or “star” configuration. Many other zoning sys-tems utilize “home run” wiring that requires all com-munication cables to be brought back to a central pointadding additional cost to the project and complicatingwiring.

High Integrity CommunicationsMany communicating control systems are susceptibleto electrical interference. One major manufacturer ofzoning systems recommends that their communicationcable should not be strapped to conduit because of po-tential interference. The Orion Systems have a com-munication bus that is almost immune to any noise orelectrical interference problems that can be found inmany commercial facilities.This feature makes instal-lation problems non-existent and insures the continuedreliability of the controls system.

Microprocessor ControllersAll controllers in the Orion System have an on boardmicroprocessor. This is what gives the Orion its power-ful features and capabilities not found in other systems.

Stand Alone SystemsAll Orion Systems are true stand-alone and do not re-quire a computer to operate. Unit controllers maintaintheir own 7 day time clock, 365 day holiday schedul-ing, and setpoints within each controller.

Menu Driven Operators’ InterfaceAll Orion systems have the ability to be connected toan operators’ keypad and display terminal. This givesyou access to system status and parameter values with-out the need for a computer. The Modular Service toolor the Modular System Manager have 4 line by 20 char-acter displays that are backlighted making them easy toread even in low light environments. Function keys andmenu driven programming makes the system extremelyuser friendly. In addition, the interface panel is pass-word protected to keep unauthorized users from access-ing the system.

Communications Via Optional ModemThe Remote Link is used for achieving remote commu-nications with the Orion system. It connects to theCommLink II communications interface and a localphone line. With the Remote Link, the Orion systemcan be programmed and monitored from a remote loca-tion, using a computer and the Prism graphical com-puter front end software package. An internet interfaceis also available when using the Prism software pack-age.

Modulating, Heavy Duty Actuators withReal Time FeedbackAll Orion actuators utilize true modulating control un-like many systems, which are two position. This givesthe system-improved control, which translates, to bet-ter comfort levels. Our actuators are also rated for 2.5million cycles, making our actuators some of the mostreliable in the industry. One other critical feature is thereal time feedback. Many other systems have no feed-back at all. They blindly estimate the travel time of theiractuator, which, in the real world, is not a very repeat-able estimate. To help correct the problems inherentwith this approach, they recycle all the actuators in thesystem once or twice a day. They may save a few dol-lars by not including feedback but they sacrifice sys-tem performance. Not so with Orion.

Commercial Grade – Insulated RoundZone DampersOrion Systems utilize commercial grade zone damp-ers, not cheap, flimsy, “light commercial” or “residen-tial” style dampers like many other manufacturers. Ourround damper is ARI certified and comes from the fac-tory fully insulated. Why? When many zone dampersare installed they are improperly insulated or not insu-lated at all. This can cause problems with the damper“sweating” from condensation. With factory insulatedzone dampers, we eliminate a common problem for thecontractor while insuring the end user will not haveproblems with condensation dripping down onto theceiling.

Rectangular DampersOrion uses only top of the line, aluminum air foil rect-angular control dampers. No other zone system on themarket today utilizes a damper of this quality and per-formance!

10 Orion Systems

Zoning Design Guide

What Is Unique About Orion?

Patented Flush Mount Room SensorsOur flush mount room sensors are so unique, they arepatented (U.S. Patent No. 4,659,236). Even though partof the sensor is recessed into the wall to provide anattractive yet tamper proof flush mounting, internal walltemperatures do not influence the sensor. A special plateon the face of the sensor accurately senses space tem-perature. Even though the attractive off white plastichousing is a preferred color, the sensor housing can bepainted or wallpapered to blend with room decor with-out affecting sensor performance. The sensors are of-fered in four different configurations:

• Sensor

• Sensor w/override

• Sensor w/setpoint adjustment

• Sensor w/setpoint adjustment & override

Modular ConnectionsThe VAV/Zone Controllers used with the Orion Sys-tem are designed with modular connections for easy,error free wiring. A Power/Comm board is used to sup-ply power and communications to the branch circuits.The VAV/Zone Controller boards and the Power/Commboard are provided with Molex connectors. Prefab-ricated cables with Molex connectors are supplied invarious lengths for connection between the VAV/ZoneControllers and the Power/Comm Board. In addition tothe power and communications wiring between thePower/Comm Board and the VAV/Zone Controllersmany Orion auxiliary devices are connected to the con-trollers via modular plugs like the ones used on tele-phones. This also simplifies installation and eliminatesthe possibility of wiring errors. The devices, which uti-lize this method are the damper actuators for zone con-trol, modular room sensors used with the zone control-

lers, auxiliary relay boards, and static pressure/air flowsensors. There is one interesting side note about theauxiliary relay board and airflow sensors. These devicesare typically used on the zone controllers in the Orionsystems. When the system is powered up, it automati-cally looks to see if these devices are connected to thecontroller. If they are, the controller automaticallyreconfigures itself to utilize these devices and activatesthe appropriate set up screens back at the operators in-terface. This feature makes setup a breeze!

FREE! Windows™ Graphics SoftwareEach Orion system can be monitored on site or remotelyusing a PC and our Windows 98, “Prism” computer frontend software. This full-featured package is very userfriendly and can be used to monitor one system or hun-dreds. Prism is not copy protected so it can be installedon multiple PC’s’ without additional expense. Just someof its many features include but are not limited to:

• Pre-designed status screens for all controllers

• Alarm dial out capability

• Programming of all system parameters

• Trend logging

• Alarm Handling

• Custom graphics capability

Open Protocol SystemOrion is an open protocol based system allowing othermanufacturers to develop direct interfaces to the com-munications loop. This gives you the ability to inte-grate the Orion system into products from other ven-dors. Our engineering staff will be glad to assist anyvendor in this process.

Orion Systems 11

Zoning Design Guide

This is a summary of the key items you need to con-sider for the design and layout of a successful zoningsystem.

It is important that you study the design guide for amore in depth understanding of proper system design.

By following the design guide and these tips you caneliminate many unnecessary headaches that occur whenthe basic rules of zoning are not followed. Always con-tact WattMaster Controls if you have any questions.

• Always group zones with similar load

profiles on the same HVAC unit.

• Never mix perimeter zones with interior

zones on the same HVAC unit.

• Each zoned HVAC unit should have a

minimum of 3 to 4 zones. Any less and you

should consult the factory.

• Each zoned HVAC unit can support a

maximum of 16 voting zones. Any more

zones and you should contact the factory.

• When using auxiliary heat for individual

zones, perimeter heat such as baseboard is

always preferred and more economical to

operate than a fan terminal unit with reheat

• If you have electric reheat coils mounted on

terminal units, it is recommended these be

fan powered terminals. Consult the factory

for further details concerning this application.

• If there is an economizer on the HVAC unit,

it is highly recommended, though not

required, that the Orion HVAC unit controller

controls the economizer.

• Pressure Independent Zones must always use

round dampers or VAV boxes, never

rectangular - no exceptions!

• Never attempt to use a zone control system

on a true VAV application. See “ Zoning

Systems Versus True VAV Systems” on page

5 of this guide for detailed information.

• Bypass dampers should always be sized for

60%-70% of the HVAC units rated CFM

• Even though the Orion system has

certain features to help protect your

equipment, never override or disconnect any

safety devices associated with the HVAC

unit

• To prevent low load cycling of the

equipment, a hot gas bypass system on the

first stage of cooling is highly recommended

Basics of Designing A Zoning System

12 Orion Systems

Zoning Design Guide

Design Considerations

Load DiversityA zoning system is designed to improve tenant comfortby dynamically rebalancing the air distribution whenused with a typical constant volume rooftop heating/cooling unit. If zones with extremely different load con-ditions are serviced by a single rooftop unit, the resultwill be poor control and excessive wear due to cyclingof the equipment.

It is especially important to avoid mixing interior zones(which require cooling all year) with exterior zones(which may require constant heat during winter months).If you must mix zones under these conditions, considerusing either VAV boxes with heat or separate externalheat on perimeter zones. Orion Zoning systems offer avariety of methods to control additional zone heat tohelp you avoid problems.

Group similar loads on an individual unit and use morethan one zoned unit if required. Any special loads canbe handled by using separate constant volume units.

The Orion Plus system offers the designer considerableflexibility by allowing both multiple-zoned units andsingle-zone units to be connected within a single simplesystem.

Cooling - Partial Load ConditionsThe engineer must be aware of several potential prob-lems when applying a zoning system for cold weatheroperation.

1.) Low Ambient Temperature Lockout. During verycold weather it is common for mechanical systems tohave “low temperature lockouts” which protect equip-ment from damage if operated under these conditions.Orion also provides user programmed lockouts for pro-tection purposes, although mechanical safeties shouldalways be used as the final stage of protection.

If the rooftop unit services interior zones with thermalloads, which require cooling when outside temperaturesare below the safe operating limits for your equipment,you should seriously consider installing an economizeron your rooftop unit. The Orion control system is de-signed to take advantage of an economizer if it is in-stalled. The use of an economizer will save money on

utilities and provide comfort under conditions when itis not possible to operate the mechanical cooling sys-tem.

2.) Low Supply Air Temperatures. Under lightlyloaded conditions much of the supply air may be by-passed back into the return air side of the HVAC unit.This bypassing will result in the lowering of the supplyair temperature, which may result in the supply air tem-perature reaching the low temperature safety limit. Ifthe supply air low temperature safety limit is exceeded,the control system will “cut off” the mechanical cool-ing to protect it from damage. Excessive cycling of themechanical system will result if this condition persists.Comfort may also suffer if the system cannot run longenough to satisfy cooling demands.

A number of things can be done to reduce this problem.Some of these things depend upon the type of installa-tion.

Avoid oversizing the unit. Do the system load calcula-tions carefully. Since the zoning system directs the heat-ing or cooling to the zones which require it, you mayfind that you can use a smaller unit in many cases. Over-sizing is the number one cause of excessive low supplyair temperature cycling.

Always specify that the unit is equipped with hot gasbypass on the first stage of cooling. This will allow theevaporator coil to operate at minimum loads withoutthe system cycling due to low temperature or pressuresafety limits and will in turn maintain the supply airdischarge temperature within a preferred range.

Use an economizer. Although this is not a cure-all, itgreatly improves operation during cool weather whencooling loads are minimal. Using an economizer alsoimproves ventilation and lowers operating costs.

Increase cooling minimum airflow. Increase your cool-ing minimum airflow or damper position settings to al-low more air during cooling operation. Be careful toavoid minimum settings that are so high they may causeover cooling of the spaces.

Bypass the air into the ceiling plenum. If you have asystem without ducted return, bypass the air into the

Orion Systems 13

Zoning Design Guide

Increase your static pressure setpoint. This will helpreduce the amount of air being bypassed. Be aware ofincreased noise levels and the cost of operation if youuse excessive static pressures. This will not work if youare using pressure independent zone controllers, sincethey will maintain a constant flow of air to the zonesregardless of duct static pressure. This technique willlikely cause over cooling of the spaces due to increased

airflow at minimum positions.

Warning:

If the fan system has the capability of producing staticpressures which could damage ductwork you must pro-vide a manual reset, high pressure limit switch (Dwyer1900-5-MR or equal) to cut off the fan system in theevent of high duct static. Do not use your Orion Zon-ing system as a safety device!

Heating - Partial Load ConditionsHeating difficulties are less common than cooling dif-ficulties. They are similar in nature, however, and thecures are generally the same. Again, a number of thingscan be done to reduce the effects of this problem.

Increase heating minimum airflow. Increase your heat-ing minimum airflow or damper position settings toallow more air during heating operation. Be careful toavoid minimum settings that are so high they may causeover heating of the spaces.

Increase the static pressure. Set the static pressuresetpoint to be as high as practical. Increasing static pres-sure does not help if you are using pressure indepen-dent control operation.

Avoid oversizing the unit. Do your all load calculationscarefully. Since the zoning system directs the heatingor cooling to the zones which require it, you may findthat you can use a smaller unit in many cases.

Bypass the air into the ceiling plenum. If you have asystem without ducted return, bypass the air into theceiling plenum instead of into the return air intake. This

method works best with plenum returns. Do not usethis method with ducted returns

Use auxiliary heat . Use an auxiliary heat source ineither your VAV boxes or use baseboard heaters.

Orion has a number of auxiliary heat control optionswhich provide solutions to most problems. Refer to theAuxiliary Heat Control Options topic near the end ofthis section.

Override ConditionsAfter-hours overrides can produce aggravated partialload conditions in both the heating and cooling modes.A single zone being overridden for after-hours use mostcommonly causes the problem. This causes the rooftopequipment to operate for only one zone. The Orion sys-tem offers an improved solution to this common prob-lem by allowing a single override to trigger a group ofzones via a “global” override. This allows the systemto operate with sufficient load to reduce cycling causedby light load conditions.

Building PressurizationIf you are using an economizer, building pressurizationmust be addressed. Failure to properly handle buildingpressurization may result in doors remaining open whenthe economizer is operating. Pressurization problemscan render economizer operation useless. The follow-ing suggestions will help to avoid potential problems.

Use powered exhaust. A power exhaust fan(s) must beused when the system utilizes ducted returns. The re-turn duct pressure drop will cause most barometric re-lief dampers to function poorly or not at all. Orion hasthe ability to control a powered exhaust whenever theeconomizer is operating.

Use building pressure control. The Orion VAV/CAVController can be configured to control building pres-sure with the addition of a building pressure sensor.The controller will modulate a VFD equipped exhaustfan or control a modulating exhaust damper to main-tain a specific building pressure setting..

14 Orion Systems

Zoning Design Guide

Zoning Design Procedures

GeneralThere are six basic steps to designing an Orion Zoningsystem:

1.) Determining the number and location of zones

2.) Sizing the central unit

3.) Duct Considerations

4.) Room air motion and diffuser selection

5.) Bypass damper sizing

6.) Sizing the zone dampers

Step #1 - Determining The Number AndLocation Of ZonesA single HVAC unit should have no more than twentyzones and no fewer than 3 zones. If the number of zonesexceeds twenty, then more than one HVAC unit maybe required to service the zones. Please consult the fac-tory for situations that are borderline.

The primary precaution to be taken in applying the OrionZoning System is to select the zoning so that no zonewill be at maximum (design) heating (or cooling) loadwhen any other zone requires the opposite temperature

air to satisfy its load. For example, depending on thewall, ceiling and floor material and location within thebuilding (e.g. top or middle floor), a typical floor of abuilding usually has several distinct temperature or con-trol zones that are affected uniquely by the outdoor load.These zones are depicted in Figure 1-2.

Depending on the size of the building and partition lay-out, some of these zones may overlap or be insignifi-cant from a zoning standpoint. For example, Zone 11could be multiple conference or computer rooms whereadditional zoning would be required, or it could be assmall as a corridor where no zoning is required. Simi-larly, zones 7 and 8 could have no external windowsand no partitions between them and could be consid-ered a single zone. Some zones could be divided intomultiple offices with full partitions between them, thusrequiring separate Zone Controllers because of differ-ent internal loads, but the same external load.

Generally, the greater the number of individual ZoneControllers, the greater the comfort. The designer willhave to look at the specific building, balancing the costsof multiple zones with the added comfort possible withmultiple zones, to match the owner’s requirements.

It is important to recognize that there are purely inter-nal zones, such as Zone 11 in Figure 1-2, which maycontain separate offices/conference/computer rooms.These internal zones could easily have high cooling re-quirements while external zones (1,2,3, etc.) could beat or near design heating load. This is a misapplicationof the Orion, zoning (or any heating/cooling change-over) system. The interior zones with cooling only loadsshould be served by a separate single zone rooftopHVAC unit (that could be zoned between multiple roomswith a similar load profile). Supplemental heat couldbe added to the perimeter zones and controlled with theauxiliary heat control board from the Zone Controller.System performance will generally be compromised andfrequent change-over from the heating to the coolingmode will occur during the heating season if purely in-ternal zones are combined on the same air-condition-ing unit serving perimeter zones. The exposure to thesun has a large affect on the loading of the building.With the building zoned as shown below, for the bestcontrol, zones 6, 7, 8, 9 and 10 should be put on oneHVAC unit, and zones 1, 2, 3, 4 and 5 on another HVACunit. Zone 11 should be on a separate single zone con-

Figure 1-2: Zones Affected by the Outdoor Load

� � �

�

���

� ��

�

�

Orion Systems 15

Zoning Design Guide

Figure 1-3: Zone Layout With External Zones Only.

�

�

�

� �

�

�

�

Here is another example of the building’s exposure af-fecting the zoning. Figure 1-3 below shows a buildinglayout with 7 zones, it has 3 zones with an eastern ex-posure, 4 zones with a western exposure and two eachnorth and south exposures. This building can be con-trolled from a single, constant volume air handler. Allof the zones have exterior surfaces and there are nototally internal zones, so they should have similar loadrequirements.

Figure 1-4 shows a building with 7 zones, 4 of the zoneshave a north exposure and the other 3 have a south ex-posure. Since there is a big difference in the affect onthe building between north and south exposures, thissituation should use two zoned HVAC units.

Figure 1-5 shows a combination manufacturingfacility and office area. The space temperature in theindividual zones numbered 1 through 6, would all becontrolled by a single HVAC unit. A single constantvolume HVAC unit would be used for each of thezones 7 through 12.

� � � �

���

�

������

� �

�

Figure 1-5: Zoning And Constant Volume Units

Figure 1-4: Zones With North And South Exposures.

16 Orion Systems

Zoning Design Guide

Step #2 - Sizing the Central UnitBecause the zones are controlled with variable air vol-ume, it is unlikely that all zones will be at design loadat the same time. The zoning allows for the diversity ofloads to be taken into account and will often providebetter comfort with a smaller HVAC unit.

In sizing the system, the individual zone loads shouldbe calculated using any dependable load estimatingmethod. Because of diversity, the central unit shouldbe selected for the instantaneous peak load, not the sumof the peak loads, as would be done with a constantvolume single zone system. Consider the followingwhen sizing the central unit.

• Size the peak cooling load based on themonth day hour of the greatest total buildingsystem load

• Heating should be sized for the lowest designtemperature with an additional margin formorning “pickup”. This margin is generallyrecommended to be 20 to 25 percent of basedesign.

Step #3 - Duct Design ConsiderationsThe Orion system uses a typical low pressure duct de-sign. To reduce noise problems duct pressures shouldnot exceed 1 inch W.C.

Primary trunk ducts should not be “undersized.” Thisis especially true for “pressure dependent” systems.Pressure dependent refers to the typical Orion ZoneController without the airflow sensor. With larger trunkducts, it is easier to assure relatively constant pressureto each zone. Runs should be as short as possible, andthe trunk duct system kept as symmetrical as possibleto facilitate system balancing. Wherever possible, runthe trunk ducts above corridors and locate the zonedampers above corridors to reduce the noise in the spaceand facilitate service of the units. Trunk ducts shouldbe sized for no more than 0.1 inch W.C. drop per 100feet., and a maximum duct velocity of 2000 FPM.

Note For pressure independent terminal unitswith velocity sensors and conventional“VAV” boxes properly selected for“quiet” operation, this 2000 FPM rulecan be exceeded by up to 50 percent. Thedesigner, however, should be veryexperienced in VAV system design beforeconsidering modification of this generalrule.

Typical VAV systems with pressure independent termi-nals use the static regain method for sizing ducts. Thetypical Orion Zoning system is a low-pressure, pres-sure dependent system that utilizes conventional uni-tary air-conditioning units. These systems should usethe equal-friction method of sizing the ducts, and usethe maximum loss of 0.1 inch per 100 feet as describedabove.

Step #4 - Air Motion/Diffuser SelectionAir motion is a consideration for occupant comfort. Theselection of diffusers for an Orion Zoning system re-quires more care than a constant volume system due tovarying flow of air into the zones. Slot diffusers arerecommended due to their superior performance at lowairflows. Because the zone airflow is variable volume,lower cost round or rectangular diffusers that were sat-isfactory for constant volume may prove unsatisfactorywith an Orion Zoning system. These diffusers may re-sult in “dumping” of the cold air at low flows in thecooling mode, and insufficient room air motion at lowair flows in the heating mode. Although high air mo-tion in the heating mode can be undesirable, a slot dif-fuser with a high induction ratio generally helps to re-duce room air “stratification” when the heating comesfrom a ceiling diffuser. Linear slot diffusers should beproperly selected for the airflow and “throw” suited tothe specific installation or zone.

Additional factors to consider in diffuser selection issound level and throw at design flow. Generally, mul-tiple diffusers will result in lower sound levels in thespace, but this must be balanced with the additionalhardware and installation costs. It is commonly recom-

Zoning Design Procedures

Orion Systems 17

Zoning Design Guide

mended that slot diffusers be located near the perim-eter or outside wall with the airflow directed into theroom. Consult your diffuser supplier or catalog forproper diffuser sizing and location.

Series fan boxes may be used instead of zone damperswhere higher induction rates are desirable. If the heatloss on perimeter walls is high, such as large areas ofglass, the use of Series Fan Boxes may be indicated tomaintain higher induction rates to offset “downdrafts.”If the heat loss is greater than 275 BTUH/linear foot,you should use high quality slot diffusers next to theouter wall with the airflow directed inward to counter-act downdrafts during heating. Serious downdraft prob-lems occur when heat losses exceed 400 BTUH/linearfoot and both high induction diffusers and series fanboxes are recommended.

Step #5 - Bypass Damper SizingThe function of the bypass damper is to allow a con-stant volume air handling unit to be used with variablevolume zone dampers. The bypass damper modulateson a signal from a duct static pressure sensor to “by-pass” air from the supply duct back into the return airduct. If the duct static pressure exceeds the adjustable

setpoint, then the damper opens to bypass more air, andif the static pressure drops below the setpoint, it closesto bypass less air.

Using a load calculation program, the bypass dampershould be sized to give you the maximum CFM of airto be bypassed, typically 60 to 70 percent of the HVACunits rated capacity.

To size the damper, select a damper from the table basedon calculated bypass CFM and a maximum velocitybetween 1750-2250 FPM. When determining the by-pass duct size, be sure to take into account any transi-tion fittings and associated pressure drops. (See Tables1-1 & 1-2: Damper Sizing Charts)

Whenever possible, use a single bypass damper andround duct for the bypass. If space limitations or totalairflow requires it, multiple bypass dampers can be con-trolled in parallel or a rectangular damper may be used.For proper control of the Bypass Damper, the static pres-sure sensor location is very important. Refer to Fig-ures 1-8 Thru 1-10 for proper sensor installation loca-tion information and guidelines.

Figure 1-6: Round Bypass Damper Figure 1-7: Rectangular Bypass Damper & Kit

18 Orion Systems

Zoning Design Guide

Fan

RA SensorSA Sensor

Return Air Duct

Supply Air Duct

SP Pickup

Bypass Damper

SP Sensor

Figure 1-10: Least Desirable Sensor Location

If the supply duct comes directly from the unit and im-mediately splits in opposite directions, the pressurepickup should be located ahead of the split, or as closeto it as possible, even if the bypass damper(s) are lo-cated downstream of the split.

Step #6 - Sizing Zone DampersUse a load program to determine the peak load for eachzone. These calculations will be used in selecting theappropriate zone damper sizes.

Using the maximum acceptable velocity for a branchduct (typically 1000-1500 FPM for minimal noise), findthe smallest damper that will deliver the required CFMas determined by the load program.

Locate the branch velocity used in the duct design pro-gram on the left hand column of either the round orrectangular damper sizing chart (Table 1-1 or Table 1-2). Move across the chart and find the damper whichwill provide the acceptable CFM to meet your specificzone requirements.

Note Compare the damper size selected againstthe duct size to determine if the next sizeup or down will provide acceptableperformance without requiring a transi-tion fitting.

The master zone damper can have up to 2 additionaldampers slaved together with it for large zones. Thisshould be reserved for situations when it is not practi-cal to use a single large damper. Each zone damper mustbe sized for an equal portion of the total CFM requiredfor the zone. The slaved zone(s) track the master zonesmodulation, therefore only pressure dependent controlis allowed when zone dampers are slaved.

Fan

RA SensorSA Sensor

3D

Min.

2D

Min.

Return Air Duct

Supply

Air

Duct

SP Pickup

Bypass Damper

SP Sensor

Fan

RA Sensor

SA Sensor

Return Air Duct

Supply Air Duct

Tubing To Be EqualLength And Size

Bypass Damper

SP SensorSP Pickups

If the trunk ducts are properly sized for minimum pres-sure drop, the location of the static pickup probe is notparticularly critical. It should ideally be located at rightangles to the airflow in a straight section of the supplyduct approximately 2/3 the distance of the total lengthof the supply duct. Also the probe should be locatednot less than 3 duct diameters downstream and 2 ductdiameters upstream of any elbow or takeoff. See Fig-ure 1-8.

Figure 1-8: Preferred Sensor Location

Figure 1-9: Acceptable Sensor Location

Since the “ideal” location is often difficult to find in aninstallation, a location in the main trunk where the tipis not in a “negative pressure area” (e.g. just downstreamof the inside curve of an elbow) or an area where thetube opening is directly impacted by the velocity of thesupply air. See Figure 1-9.

Zoning Design Procedures

Orion Systems 19

Zoning Design Guide

Pressure Dependent DampersWith pressure dependent (PD) dampers, the minimumand maximum airflow is set based on damper position.During the final commissioning of the system, each zoneis typically balanced with a flow hood and the min/maxposition is fixed either mechanically or the preferredmethod, in the controller software. Since this min/maxsetting is based only on position, as the static pressurefluctuates it will cause the actual airflow at the zonedamper to increase or decrease. Therefore the name,pressure dependent since the airflow is dependent onthe static pressure. Pressure dependent dampers areavailable in round or rectangular configurations. SeeFigure 1-11 for a diagram of a typical pressure depen-dent zone damper.

Pressure Independent DampersWhen using pressure independent (PI) dampers thisminimum and maximum is set based on actual CFM ofairflow through the damper. Airflow is measured usinga pickup tube mounted in the zone damper and an elec-tronic air flow sensor. Using this method you alwaysknow the actual airflow through each zone damper in-stead of just the damper percentage open. The mini-mum and maximum settings are based on this actualairflow reading. As the static pressure fluctuates, theflow sensor reads the variation and automatically repo-sitions the damper to maintain the minimum or maxi-mum flow setpoints. Since the minimum or maximumairflow is maintained independently of the static pres-sure available in the duct it is called pressure indepen-

Figure 1-11: Pressure Dependent Damper

Figure 1-12: Pressure Independent Damper

dent operation. Pressure independent operation is avail-able for round zone dampers only. Pressure indepen-dent rectangular dampers are not available. See Figure1-12 for a diagram of a typical pressure independentzone damper.

When pressure independent dampers are used they mustbe field calibrated so the CFM of airflow for the mini-mum and maximum airflow setpoints will be correct.This should be done by the field technician during thecommissioning portion of the system installation. TheK-factor is the amount of airflow in CFM that the spe-cific damper will produce with 1” W.C. velocity pres-sure on the damper flow sensor. This K-factor is usedby the controller software to maintain the correct mini-mum or maximum airflow setpoint regardless of thestatic pressure in the duct. The K-factor and the mini-mum and maximum damper CFM can be entered byusing the System Manager, or Modular Service Tool.K-factors can also be entered using a personal com-puter with the Prism computer front end software in-stalled. The K-factors for each damper size are listed inTable 1-1: Round Air Damper Selection. Once the cor-rect K-factors and minimum and maximum damperCFM setpoints are entered, the damper will modulateto try to maintain these CFM airflows during damperoperation. If zone dampers or fan terminal units manu-factured by others are used, the correct K-factors mustbe obtained from the equipment manufacturer.

20 Orion Systems

Zoning Design Guide

Zoning Design Procedures

Bypass Dampers

Zone Dampers

1/2" Foil FacedInsulation

Actuator

Round DamperBlade Assembly

Control Enclosure(Cover Removed)

AIRFLO

W AIRFLOW

Bypass & Slave Interface

1/2" Foil FacedInsulation

Actuator

Zone Controller

Round DamperBlade Assembly

Control Enclosure(Cover Removed)

AIRFLO

W AIRFLO

W

1/2" Fo il FacedInsu lation

Actuator

Round Dam perB lade Assembly

Control Enclosure(Cover Removed)

Slave Dampers

Table 1-1: Round Damper Selection Data

Damper Round Duct Size(Area Ft2)

6”

(0.188)

8”

(0.338)

10”

(0.532)

12”

(0.769)

14”

(1.050)

16”

(1.375)

CFM @ 1” Velocity PressureAir Flow Probe “K” Factor- For Pressure

Independent Applications Only474 950 1417 2120 2908 3700

Velocity Through Zone DamperFPM

Airflow Through Zone Damper - CFM(∆PS inches W.C. With Air Damper Full Open)

750 141

(0.03)

254

(0.02)

399

(0.01)

577

(0.02)

788

(0.01)

1031

(0.01)

1000 188

(0.05)

338

(0.03)

532

(0.02)

769

(0.03)

1050

(0.02)

1375

(0.01)

1250 235

(0.07)

423

(0.04)

665

(0.03)

961

(0.04)

1313

(0.03)

1718

(0.02)

1500 282

(0.09)

507

(0.06)

798

(0.04)

1154

(0.05)

1575

0.04)

2062

(0.03)

1750 329

(0.12)

592

(0.08)

931

(0.06)

1346

(0.06)

1838

(0.05)

2405

(0.04)

2000 376

(0.15)

676

(0.10)

1064

(0.07)

1538

(0.07)

2100

(0.07)

2749

(0.05)

2250 423

(0.18)

761

(0.13)

1197

(0.09)

1730

(0.09)

2363

(0.08)

3094

(0.06)

WattMaster reserves the right to change specifications without notice

Orion Systems 21

Zoning Design Guide

Rectangular DampersThe Orion Rectangular Damper is used in applicationswhere rectangular duct is specified or required becauseof space limitations or job requirements. RectangularDampers are only available for pressure dependent ap-plications. A Rectangular Damper Kit is used in con-junction with the Rectangular Damper to provide con-trol of the damper. Rectangular Damper Kits are avail-able for Bypass, Pressure Dependent Zone and SlavedZone configurations. Rectangular Damper Kits are notavailable for pressure independent applications.

The Rectangular Damper utilizes opposed blades ofairfoil design for improved air flow control. The Rect-angular Damper frame is made of .080 thick extrudedaluminum. The blades are also made of extruded alu-minum. Blade pins are 7/16” hexagon shaped alumi-num fixed to a Celcon inner bearing rotating within apolycarbonate outer bearing inserted in the damperframe. The Damper linkage is mechanically assembledand located in the damper frame. The linkage compo-nents are constructed of aluminum, zinc and nickelplated steel. Blade gaskets are made of extruded EPDMmaterial and are secured within an integral slot on theblade. Jamb seals are of extruded TPE material for lowleakage through the damper when closed. The controlshaft is 1/2” diameter hexagon shaped rod and can beextended 9” past the damper frame for connection tothe damper actuator. The damper shaft is shipped re-tracted into the frame area and must be adjusted to therequired length in the field.

MountingThe Rectangular Damper should be mounted in theductwork according to standard duct installationpractices. The rectangular damper should be selectedfor the nominal inside duct size. All RectangularDampers are supplied with 1” flanges all around thedamper frame, making the overall damper width andheight 2” larger than the nominal inside duct size thusproviding for external flange mounting to ductwork.See Figure 1-13.

The damper shaft is shipped retracted into the damperframe. Loosen the two nuts on the U-bolt that securesthe damper shaft to the damper blade and adjust tolength. It is recommended that the shaft length beadjusted so approximately 4” of shaft extends beyondthe inside of the damper frame. Retighten the two nutson the U-bolt that secures the damper shaft to the blade.After installation of the Rectangular Damper to theductwork, it is recommended that insulation be appliedaround any non-insulated surface on the ductwork wherethe Rectangular Damper was installed.

Rectangular Damper Kit InstallationThe Rectangular Damper Kit is simply slid over thedamper shaft, the actuator shaft collar setscrewstightened and the supplied self tapping screws are usedto mount the enclosure to the ductwork. Detailedmounting and installation instructions are provided witheach kit. A knockout is provided in the front accesscover, which can be punched out to allow for dampershaft lengths, which extend past the enclosure depth.When mounting the Rectangular Damper Kit, be sureto allow clearance for removal of the access cover.Conduit knockouts are provided in the top and bottomof the enclosure for simplified wiring installation.

Rectangular Damper Kit

Rectangular Damper

Figure 1-13: Rectangular Damper & Damper Kit

Flanged Ductwork

22 Orion Systems

Zoning Design Guide

Zoning Design Procedures

T a b le 1 -2 : R ecta n g u lar D a m p e r S e lect io n D a ta

D a m p erH e igh t

“B ”8 ” 1 0” 1 2” 1 4” 1 6” 1 8” 2 0” 2 2” 2 4” 2 6” 2 8” 3 0” 3 2” 3 4” 3 6”

D a m p erW id th

“A ”

A irflow D ata w ith F ull O pen D a m per – C F M @ 10 00 F PM V elocity(∆P S - in ch es W .C . @ 1 000 F P M V eloc ity)

Fo r a irflo w C FM a t o th e r velo c itie s u se th ese m u lt ip liers : 750 F P M = 0 .75 , 1250 F P M = 1 .2 5, 1500 FP M = 1 .5 , 2 000 = 2 .0 , 2250 = 2.25

8 ” 4 10(0 .16 )

5 30(0 .10 )

6 40(0 .07 )

7 40(0 .05 )

8 50(0 .04 )

9 70(0 .03 )

1 08 0(0 .03 )

1 19 0(0 .02 )

1 30 0(0 .02 )

1 41 0(0 .02 )

1 52 0(0 .01 )

1 63 0(0 .02 )

1 74 0(0 .01 )

1 85 0(0 .01 )

1 97 0(0 .01 )

1 0” 5 10(0 .10 )

5 90(0 .07 )

6 90(0 .05 )

8 00(0 .03 )

9 10(0 .03 )

1 03 0(0 .02 )

1 15 0(0 .02 )

1 26 0(0 .01 )

1 38 0(0 .01 )

1 50 0(0 .01 )

1 61 0(0 .01 )

1 73 0(0 .01 )

1 84 0(0 .01 )

2 00 0(0 .01 )

2 08 0(0 .01 )

1 2” 5 60(0 .07 )

6 50(0 .05 )

7 30(0 .03 )

8 50(0 .02 )

9 70(0 .02 )

1 09 0(0 .01 )

1 21 0(0 .01 )

1 33 0(0 .01 )

1 46 0(0 .01 )

1 58 0(0 .01 )

1 70 0(0 .01 )

1 82 0(0 .01 )

1 94 0(-)

2 06 0(-)

2 19 0(-)

1 4” 6 60(0 .05 )

7 70(0 .03 )

8 80(0 .02 )

1 03 0(0 .02 )

1 18 0(0 .01 )

1 33 0(0 .01 )

1 48 0(0 .01 )

1 63 0(0 .01 )

1 76 0(0 .01 )

1 91 0(0 .01 )

2 06 0(-)

2 21 0(-)

2 36 0(-)

2 51 0(-)

2 64 0(-)

1 6” 7 50(0 .04 )

8 90(0 .03 )

1 03 0(0 .02 )

1 20 0(0 .01 )

1 37 0(0 .01 )

1 54 0(0 .01 )

1 71 0(0 .01 )

1 88 0(0 .01 )

2 06 0(-)

2 23 0(-)

2 40 0(-)

2 57 0(-)

2 74 0(-)

2 91 0(-)

3 09 0(-)

1 8” 7 70(0 .03 )

9 80(0 .03 )

1 18 0(0 .01 )

1 38 0(0 .01 )

1 58 0(0 .01 )

1 78 0(0 .01 )

1 98 0(0 .01 )

2 18 0(-)

2 35 0(-)

2 55 0(-)

2 75 0(-)

2 95 0(-)

3 15 0(-)

3 35 0(-)

3 54 0(-)

2 0” 8 50(0 .03 )

1 09 0(0 .02 )

1 33 0(0 .01 )

1 55 0(0 .01 )

1 77 0(0 .01 )

1 99 0(0 .01 )

2 21 0(-)

2 43 0(-)

2 65 0(-)

2 87 0(-)

3 09 0(-)

3 31 0(-)

3 53 0(-)

3 75 0(-)

3 99 0(-)

2 2” 9 30(0 .02 )

1 21 0(0 .01 )

1 48 0(0 .01 )

1 73 0(0 .01 )

1 98 0(0 .01 )

2 23 0(-)

2 48 0(-)

2 73 0(-)

2 95 0(-)

3 20 0(-)

3 45 0(-)

3 70 0(-)

3 95 0(-)

4 20 0(-)

4 44 0(-)

2 4” 9 50(0 .02 )

1 29 0(0 .01 )

1 63 0(0 .01 )

1 90 0(0 .01 )

2 17 0(-)

2 44 0(-)

2 71 0(-)

2 98 0(-)

3 25 0(-)

3 52 0(-)

3 79 0(-)

4 06 0(-)

4 33 0(-)

4 60 0(-)

4 88 0(-)

2 6” 9 90(0 .02 )

1 39 0(0 .01 )

1 78 0(0 .01 )

2 08 0(0 .01 )

2 38 0(-)

2 68 0(-)

2 98 0(-)

3 28 0(-)

3 55 0(-)

3 85 0(-)

4 15 0(-)

4 45 0(-)

4 75 0(-)

N A N A

2 8” 1 07 0(0 .01 )

1 50 0(0 .01 )

1 93 0(0 .01 )

2 25 0(-)

2 57 0(-)

2 89 0(-)

3 21 0(-)

3 53 0(-)

3 85 0(-)

4 17 0(-)

4 50 0(-)

4 82 0(-)

N A N A N A

3 0” 1 02 0(0 .01 )

1 55 0(0 .01 )

2 08 0(0 .01 )

2 43 0(-)

2 78 0(-)

3 13 0(-)

3 48 0(-)

3 83 0(-)

4 15 0(-)

4 50 0(-)

4 85 0(-)

N A N A N A N A

3 2” 1 09 0(0 .01 )

1 66 0(0 .01 )

2 23 0(-)

2 60 0(-)

2 97 0(-)

3 34 0(-)

3 71 0(-)

4 08 0(-)

4 45 0(-)

4 82 0(-)

N A N A N A N A N A

3 4” 1 15 0(0 .01 )

1 77 0(0 .01 )

2 38 0(-)

2 78 0(-)

3 18 0(-)

3 58 0(-)

3 98 0(-)

4 37 0(-)

4 75 0(-)

N A N A N A N A N A N A

3 6” 1 06 0(0 .01 )

1 79 0(0 .01 )

2 52 0(-)

2 67 0(-)

3 09 0(-)

3 51 0(-)

3 93 0(-)

4 35 0(-)

5 04 0(-)

N A N A N A N A N A N A

W attMaster reserves the right to change specifications w ithout notice

Rectangular Damper Selection ProcedureLocate the required CFM on the Rectangular DamperSelection Data table below. This table is based on anairflow velocity of 1000 FPM across the damper. Thisis the recommended velocity for quiet operation andnormal pressure drop through the damper. When spaceconsiderations or design criteria dictate, dampers maybe selected for other face velocities by using themultipliers listed in the notes associated with the table.Move across the table and find the damper selection,which will provide the required CFM and fit withinthe ceiling area where the damper will be located.Pressure drop across the damper is shown in parenthesisbelow the CFM

Orion Systems 23

Zoning Design Guide

Auxiliary Heat Control OptionsThe Orion Zoning system offers the user a variety ofmethods to deal with zone heating requirements. Inorder to control zone heat, an optional Relay ExpansionBoard is required. When deciding how to handle zoneheating requirements the user should consider thefollowing:

• Does the rooftop unit have heat?• Are you using fan-powered boxes with reheat?• Is auxiliary heat, such as baseboard or radiant

ceiling panels being used?

If the zone has some type of heat, the user must considerhow the heat is to be used. The following are thingsthat should be considered when configuring theauxiliary heat.

Using the zone heat as a first stage where it will becomeactive before a heating demand is created at the rooftopunit. This mode is useful if you expect to have bothheating and cooling demands at the same time. Thezone will use it’s own heat and allow the rooftop unitto continue to provide cooling for other zones. Thismode is also useful if the roof top unit does not haveany heating capabilities.

Using the zone heat only as a second stage, where itwill be activated only if the roof top unit cannotmaintain the space temperature, such as during verycold weather? In this mode of operation the rooftopwill examine the heating and cooling demands and tryto satisfy all of the zones by switching between heatingand cooling as required. The zone heat will only beactivated if the zone temperature falls below a fixedlimit from the setpoint.

The zone heat is locked out if the rooftop unit issupplying hot air. Many times it is desirable to use therooftop heating whenever possible and only use zoneheat when the rooftop unit is in cooling. This mode ofoperation will lockout zone heat if the rooftop isdelivering heated air that is 10° above the heatingsetpoint.

Zone Controller Expansion BoardsThe following describes the operation of each of therelays on the optional OE 321 Relay Output ExpansionBoard and the optional OE322 Analog/Relay OutputExpansion Board. Both boards have 3 usable relayoutputs. The OE322 Analog/Relay Output Board inaddition, has a 0-10VDC analog output for control of amodulating hot water valve.

Output #1 - Relay Output - Series or Parallel FanIf the VAV/Zone controller is configured for Series Fanterminal, this output will be energized anytime the mainHVAC unit is on. If the controller has been configuredfor Parallel Fan operation, this output will energizewhen the zone temperature drops below the heatingsetpoint. It deactivates when the temperature rises 0.5°above the heating setpoint. This output can also beconfigured to activate when the damper closes to aminimum position or a minimum CFM for pressureindependent zones.

Output #2 - Relay Output - HeatThis heat output can activate anytime the zonetemperature drops below the heating setpoint. Itdeactivates when the temperature rises 0.5°F above theheating setpoint. In the unoccupied mode, theunoccupied heating setpoint, with adjustable deadbandvalues, is used. This allows the zone to maintain a lowerheating setpoint at night than it does during the daytime.This heat output is not allowed to activate if the airbeing supplied by the air handling unit is 10° or moreabove the heating setpoint. This output is intended toallow zone reheat while the Polling Device is satisfyingcooling demands in other zones. This output is alsointended to allow zone heating to augment the normalheating mode and to allow a zone an attempt to satisfyits own heating needs before creating a heating demandat the Polling Device.

Output #3 - Relay Output - HeatIn the occupied mode, this heat output will activateanytime the zone temperature is 1.0°F below the heatingsetpoint. It deactivates when the temperature rises to0.5°F below the heating setpoint. In the unoccupiedmode, the unoccupied heating setpoint, with the samedeadband values mentioned above, is used. This allowsthe zone to maintain a lower heating setpoint at nightthan it does during the daytime.

Output #4 - OE321 Relay Output Board (Not Used)Output #4 - OE322 Analog/Relay Output Board(Modulating Hot Water Heat)This relay output is not used on the OE 321 RelayOutput Expansion Board. On the OE 322 Analog/RelayOutput Board, it supplies a 0-10VDC or 2-10VDCsignal to control a modulating hot water valve. Theoutput voltage starts to increase from minimum as thespace temperature drops to 0.5°F above the heatingsetpoint and will be at the full 10 volts when the spacetemperature is 1.5°F below the heating setpoint.

24 Orion Systems

Zoning Design Guide

System Installation

Mounting Of ControllersAll Orion Round Dampers or Rectangular Damper Kitshave the required controllers, actuators etc. factorymounted in an indoor rated control enclosure. If youwish to use another manufacturers dampers for zoningcontrol you must purchase Zone or Bypass Packagesfrom WattMaster. These are furnished without a mount-ing enclosure. Most local codes require these compo-nents be mounted in an enclosure. If yours does notrequire this it is still strongly recommended that you domount them in an enclosure. Components that are notin an enclosure are in danger of being damaged, andare susceptible to dirt and moisture contamination. Youmay furnish your own enclosure or one is available fromWattMaster. The part number for the WattMaster en-closure is EE000075-01. This is an indoor rated enclo-sure. If the zone mounting location is susceptible towater damage, watertight enclosures can be purchasedat any local electrical supply. Mounting location for thecontrollers should not violate any local, state or nationalcodes.

System WiringWiring requirements for Orion systems can be brokendown into four main categories:

1.) Power Wiring

2.) Communications Wiring

3.) Controller Wiring

4.) Sensor Wiring

The Orion System utilizes two different methods ofconnecting the above categories of wiring between thecomponents on the Orion system. Some devices utilizestandard terminal to terminal wiring while other devicesutilize modular wiring connections with prefabricatedcables being used to connect the devices to each other.

VAV/Zone Controllers, the Modular System Managerand the Modular Polling Device power and communi-

cations wiring is achieved by using a Power/Comm dis-tribution board and prefabricated modular cables. Thesecables distribute the power and communications sig-nals to each modular device connected to the Power/Comm board(s). These devices also use modular con-nections for all sensor wiring.

All HVAC Unit Controllers such as the VAV/CAV Con-troller, MUA Controller and the HCCO Controller useterminal to terminal wiring for power, communications,sensor and controller wiring. The GPC Controller, GPC-17 Controller, Lighting Panel Controller and the Opti-mal Start Scheduler also utilize this wiring method.

Standard Terminal to Terminal Power WiringAll Orion Unit Controllers and Add-On Devices arepowered by 24 VAC. It is possible to power these byusing one or more common transformers or individualtransformers for each device. Possible problems youmay encounter using common transformers to powermultiple devices are:

• Polarity Must Be Maintained BetweenDevices Connected To A CommonTransformer. If polarity is not maintained, shorting of thetransformer will occur resulting in damage tothe system electronics.

• It is important when powering multiple devicesfrom one transformer that total VA load andwiring voltage drops be taken into account. Forproper sizing of the transformer and wire seeFigure 1-16.

It is therefore recommended that in most installationsindividual transformers be installed for each device.This will greatly reduce the possibility of errors andpossible damage to the system.

Power wiring should always be done in accordance withany local, state, or national codes.

Orion Systems 25

Zoning Design Guide

Modular Power/Communication WiringAs previously described, VAV/Zone Controllers, theModular System Manager and the Modular PollingDevice, power and communications wiring is achievedby using a Power/Comm distribution board and prefab-ricated modular cables. The items below must be con-sidered when sizing and wiring the modular devices:

• Size the transformer for the correct VA loadbased on the type and number of devices tobe connected to each Power/Comm Board.The largest transformer that may be used topower the Power/Comm Board is 100VA.For transformer sizing of devices withmodular connectors, seeFigure 1-17.

• Do Not Ground The Power/Comm BoardTransformer!If the Power/Comm Board transformer isconnected to earth or chassis ground, the

Power/Comm Board and all devicesconnected to it will be damaged.

• Each Power/Comm Board has 4 individualbranch circuit connectors. No more than 6devices may be connected to an individualbranch circuit. If more connections areneeded, add another Power/Comm Board.

• The maximum total length of cables allowedon a single branch circuit is 240 feet. Ifdistances to the devices would be greater thanthis, add another Power/Comm Board at alocation that is closer to the farthestcontroller(s).

The modular wiring and prefabricated cables virtuallyeliminate power and communications wiring errors.Simply plug in the cables between modular connectors.

Prefabricated Power/Comm Cables are available in 25,40, 80 and 120 feet lengths. Power/Comm ExtensionCables are available in 10 and 20 feet lengths. Withthese cable assemblies and extensions, almost any com-munications cable length desired can be achieved withthe least number of connections. Always use the short-est Power/Comm Cable Assembly between devices soas not to exceed the maximum branch circuit cablelength requirement of 240 feet.

Communication LoopsThe Orion system utilizes two different communica-tions loops. These are the network loop and the localloop. Communication between devices on each localloop are via a 9600 Baud communication rate. Com-munications between devices on the network loop uti-lize a 19200 Baud communications rate. All modularcontrollers (as previously discussed under the modularpower wiring) are connected by modular cable and willnot be discussed. All other controllers use terminal toterminal wiring for communications. Please refer to thefollowing information for proper communications wir-ing of the Orion system.

WattMaster requires that all communication wire be 18gauge minimum, two wire shielded cable, Belden#82760 or equivalent. WattMaster offers communica-tions cable for this purpose. The 18 gauge color coded

and labeled wire is available for the local loop and thenetwork loop communications wiring. The local loopwire is supplied in 1000 ft. spools and is labeled “LocalLoop” with a green candy stripe. The network loopwire is supplied in 500 ft. spools and is labeled “Net-work Loop” with a red candy stripe.

The loop is best connected in a daisy chain configura-tion, meaning the loop is connected from one control-ler to another. It is not necessary to sequentially ad-dress the zone controllers in relation to their locationon the loop.

Figure 1-14: WattMaster Communications Wire

Local Loop Wire

Network Loop Wire

26 Orion Systems

Zoning Design Guide

Even though the daisy chain configuration is preferred,the star configuration can also be used. If required, acombination of the two can also be used. Remember,the best communications loop wiring is the one whichutilizes the minimum number of ends while using theshortest wiring path.

Communication Wiring terminals on most Orion con-trollers are marked “T”, “R” and “SHLD” (Note: in-stead of SHLD the CommLink is marked “G”. All wir-ing should be connected T to T, R to R and SHLD toSHLD throughout the entire loop system. Communica-tion wire should be color coded to facilitate error freewiring. The communication loops will not work if anyof the wires are reversed or otherwise landed incorrectly.Communications loops can be run up to a maximum ofapproximately 4000 ft. in total length. If your systemexceeds this length, please consult the WattMaster fac-tory for more information regarding extended commu-nication loop lengths and solutions.

Caution: Unless the communications loopis installed in conduit, be careful toposition the cable away from highnoise devices like fluorescentlights, transformers, VFD’s, etc.Conduit is not required for com-munications loop wiring unlessrequired by local codes.

Tip: Incorrect wiring of the communicationsloop is the most common mistake madeduring installation. Before beginninginstallation, write down the wire colorused on each terminal connection andconsistently maintain that color code. Itis recommended that a continuous wirerun be made between devices. Anytimea splice is made in the cable you increaseyour chance of problems. If a splice mustbe made, be very sure that you have a goodconnection. Cable should be soldered andwrapped or if soldering is not possible usewire nuts or butt splices. Connectors shouldthen be wrapped tightly with electrical tape.

Caution: Make sure when you are insertingwires into the terminal blocks thatstrands of wire do not stick out andtouch the adjacent terminals. Ifadjacent wires touch each other oranother terminal, shorting andsubsequent damage to the circuitboard could result.

Controller WiringAll controller wiring should be in accordance with alllocal, state, and national codes. It is recommended thatall wire be a minimum of 18 AWG unless otherwisespecified in the charts below. Controller connectionsand wire sizing is as follows:

VAV/CAV Controller• 24 VAC Supply Voltage (8 VA)

(2) Conductors - Determine minimumwire size from Figure 1-16 on page 26.

• Communications Loop(2) Conductors 18 gauge minimumtwisted pair with shield(WattMaster communication wire,Belden #82760 or equal)

• Supply Air Temperature Sensor(2) Conductors 24 gauge minimum

• Return Air Temperature Sensor(2) Conductors 24 gauge minimum

• Outside Air Sensor(2) Conductors 24 gauge minimum

• Supply Static Pressure Sensor(2) Conductors 24 gauge minimum

• Bypass Damper(3) Conductors 24 gauge minimum

• HVAC Unit Control Wiring(6) Conductors 24 gauge minimumR (Common), G (Fan), Y1 (Cool 1),Y2 (Cool 2), W1 (Heat 1), W2 (Heat 2)For VAV/CAV Controller WithOptional Staging Expansion Board up toan additional (8) conductors Y3 throughY6, W3 Through W6

System Installation

Orion Systems 27

Zoning Design Guide

System Manager• 24 VAC Supply Voltage (6 VA)

and Communications LoopUse Prefabricated Modular Cable

VAV/Zone Controller• 24 VAC Supply Voltage (6 VA)

and Communications LoopUse Prefabricated Modular Cable

• Modular Room SensorUse Prefabricated Modular Cable

Sensor WiringOrion temperature sensors utilize a type III thermistorelement that is one of the most commonly used sensorsin the building controls industry. The sensor wire shouldbe a minimum of 24 gauge however larger wire such as18 gauge is commonly used. The exception to this isthe VAV/Zone Controller utilizes a Modular Room Sen-sor which is connected with a prefabricated modularcable.

Conventional thermostat cable is acceptable in mostcommercial and institutional installations. In some in-stallations which have the potential for high electrical

noise, such as broadcast facilities (radio, TV, etc.), heavyindustrial (machinery, welding equipment, etc.), andmedical (x-ray, scanning, etc.), it is advisable to useshielded cable on sensors which are located in or closeto these environments. The same cable used for the com-munication bus can be used in these situations.

Sensor requirements are:• Supply Air Sensor

(2) Conductors 24 gauge minimum

• Return Sensor(2) Conductors 24 gauge minimum

• Outside Air Sensor(2) Conductors 24 gauge minimum

• Standard Room Sensor (HVAC UnitControllers Only)(2) Conductors 24 gauge minimum(3) Conductors if using optional slideadjust

• Modular Room Sensor (used with VAV/Zone Controllers Only)Use Prefabricated Modular Cable

28 Orion Systems

Zoning Design Guide

System Installation

Fig

ure

1-15

: N

etw

orke

d Sy

stem

Com

mun

icat

ion

Loo

p W

irin

gEXP

AN

SIO

N

SE

NS

OR

PR

ES

SUR

E

GN

D7AINAO

UT2

AO

UT1

AIN GN

D

GN

D5AIN

AIN

AIN 432

T'S

TAT

24VA

C

NET

WO

RK

16 TOK

EN

3284

GN

D

AIN 112

V

INP

UTS

RSH

LD

T

CO

MM

1 2

YS

101

718

TU

C5

R P

LUS

COM1-3

R5 COM4-5

R4

R3

R2

R1

EXP

ANS

ION

SEN

SO

RP

RES

SU

RE

GN

D7AINAO

UT

2

AO

UT

1

AIN GN

D

GN

D5AIN

AIN

AIN 432

T'ST

AT

24VA

C

NE

TWO

RK

16 TOKE

N3284

GN

D

AIN 112

V

INPU

TS

RSH

LD

T

CO

MM

1 2

YS

1017

18TU

C5R

PLU

S

COM1-3

R5 COM4-5

R4

R3

R2

R1

EXPA

NSI

ON

SE

NSO

RP

RE

SSU

RE

GN

D7AINAO

UT2

AOU

T1

AIN GN

D

GN

D5AIN

AIN

AIN 432

T'S

TAT

24VA

C

NE

TW

OR

K

16 TOK

EN

3284

GN

D

AIN 112

V

INPU

TS

RSH

LD

T

CO

MM

1 2

YS

1017

18

TU

C5

R P

LUS

COM1-3

R5 COM4-5

R4

R3

R2

R1

LO OPLO OP

NE

TW

OR

K

NE

TW

OR

K

TT SHSH RR

24VA

C

24VA

C

GND

GND

TT SHSH RR

��

�����

���

SIG

DET

RDY

SND

REC

PWR

+V +V1 3 4 5 6 7 8 G G2

AN

ALO

GIN

PU

TS

G ND

S IG+5V

AN

ALO

GO

UT

PU

TS

A1

A2 G

��

��

��

���

��

LOOP STA

TU

S

COMP

RLINK

TB2

VAC

F1

25

4A

24

SHLD

T

R

POWER

LD1

TB1

C1

POWER & COMMDIST. BOARD YS101856REV. 0

P5

P4

P3

P1

D1

V1

R1

P2

CO

MM

P I

N

PO

WE

R &

CO

MM

O

UT

��

AC

TU

AT

OR

EX

PA

NS

ION

NET

ADD

8

3216

24

1

74

HC

57

3N

PB

31

92

0P

S SW1

U1

EE

PR

OM

EP

RO

M

PJ4

AIR

FL

OW

SP

AC

E S

EN

SO

R

PJ3

JP

2

U7

CX7

TB2

AIN

GND

AUX

U4

T

SH

LD

R

TB

1

OUT IN

P1

P2

K1

K2

PJ2

PJ1JP1

VAV Z C O NT R O L L ER PY S 1 01 8 5 4 R EV .

��

AC

TU

AT

OR

EX

PA

NS

ION

NET

ADD

8

3216

24

1

74

HC

57

3N

PB

31

92

0P

S SW1

U1

EE

PR

OM

EP

RO

M

PJ4

AIR

FLO

WS

PA

CE

SE

NS

OR

PJ3

JP

2

U7

CX7

TB2

AIN

GND

AUX

U4

T

SH

LD

R

TB

1

OUT IN

P1

P2

K1

K2

PJ2

PJ1JP1

VAV Z C O NT R O L L ER PY S 1 01 8 5 4 R EV .

��

AC

TU

AT

OR

EX

PA

NS

ION

NET

ADD

8

3216

24

1

74H

C5

73

NP

B3

192

0PS SW1

U1

EE

PR

OM

EP

RO

M

PJ4

AIR

FL

OW

SP

AC

E S

EN

SO

R

PJ3

JP2

U7

CX7

TB2

AIN

GND

AUX

U4

T

SH

LD

R

TB

1

OUT IN

P1

P2

K1

K2

PJ2

PJ1JP1

VAV Z C O NT R O L L ER PY S 1 01 8 5 4 R EV .

��

AC

TU

AT

OR

EX

PA

NS

ION

NET

ADD

8

3216

24

1

74

HC

57

3N

PB

31

92

0P

S SW1

U1

EE

PR

OM

EP

RO

M

PJ4

AIR

FL

OW

SP

AC

E S

EN

SO

R

PJ3

JP

2

U7

CX7

TB2

AIN

GND

AUX

U4

T

SH

LD

R

TB

1

OUT IN

P1

P2

K1

K2

PJ2

PJ1JP1

VAV Z C O NTR O L L ER PY S 1 01 8 5 4 R EV .

��

AC

TU

AT

OR

EX

PA

NS

ION

NET

ADD

8

3216

24

1

74

HC

57

3N

PB

31

92

0P

S SW1

U1

EE

PR

OM

EP

RO

M

PJ4

AIR

FLO

WS

PA

CE

SE

NS

OR

PJ3

JP

2

U7

CX7

TB2

AIN

GND

AUX

U4

T

SH

LD

R

TB

1

OUT IN

P1

P2

K1

K2

PJ2

PJ1JP1

VAV Z C O NTR O L L ER PY S 1 01 8 5 4 R EV .

��

AC

TU

AT

OR

EX

PA

NS

ION

NET

ADD

8

3216

24

1

74H

C5

73

NP

B3

19

20P

S SW1

U1

EE

PR

OM

EP

RO

M

PJ4

AIR

FL

OW

SP

AC

E S

EN

SO

R

PJ3

JP

2

U7

CX7

TB2

AIN

GND

AUX

U4

T

SH

LD

R

TB

1

OUT IN

P1

P2

K1

K2

PJ2

PJ1JP1

VAV Z C O NTR O L L ER PY S 1 01 8 5 4 R EV .

��

AC

TU

AT

OR

EX

PA

NS

ION

NET

ADD

8

3216

24

1

74

HC

57

3NP

B3

192

0P

S

SW1

U1

EE

PR

OM

EP

RO

M

PJ4

AIR

FL

OW

SP

AC

E S

EN

SO

R

PJ3

JP2

U7

CX7

TB2

AIN

GND

AUX

U4

T

SH

LD

R

TB

1

OUT IN

P1

P2

K1

K2

PJ2

PJ1JP1

VAV Z C O NT R O L L ER PY S 1 01 8 5 4 R EV .

��

AC

TU

AT

OR

EX

PA

NS

ION

NET

ADD

8

3216

24

1

74

HC

57

3N

PB

31

920

PS SW1

U1

EE

PR

OM

EP

RO

M

PJ4

AIR

FL

OW

SP

AC

E S

EN

SO

R

PJ3

JP

2

U7

CX7

TB2

AIN

GND

AUX

U4

T

SH

LD

R

TB

1

OUT IN

P1

P2

K1

K2

PJ2

PJ1JP1

VAV Z C O NT R O L L ER PY S 1 01 8 5 4 R EV .

��

AC

TU

AT

OR

EX

PA

NS

ION

NET

ADD

8

3216

24

1

74

HC

57

3N

PB

31

92

0P

S SW1

U1

EE

PR

OM

EP

RO

M

PJ4

AIR

FLO

WS

PA

CE

SE

NS

OR

PJ3

JP

2

U7

CX7

TB2

AIN

GND

AUX

U4

T

SH

LD

R

TB

1

OUT IN

P1

P2

K1

K2

PJ2

PJ1JP1

VAV Z C O NT R O L L ER PY S 1 01 8 5 4 R EV .

��

AC

TU

AT

OR

EX

PA

NS

ION

NET

ADD

8

3216

24

1

74

HC

57

3N

PB

31

920

PS SW1

U1

EE

PR

OM

EP

RO

M

PJ4

AIR

FL

OW

SP

AC

E S

EN

SO

R

PJ3

JP

2

U7

CX7

TB2

AIN

GND

AUX

U4

T

SH

LD

R

TB

1

OUT IN

P1

P2

K1

K2

PJ2

PJ1JP1

VAV Z C O NTR O L L ER PY S 1 01 8 5 4 R EV .

��

AC

TU

AT

OR

EX

PA

NS

ION

NET

ADD

8

3216

24

1

74H

C5

73

NP

B3

19

20P

S SW1

U1

EE

PR

OM

EP

RO

M

PJ4

AIR

FL

OW

SP

AC

E S

EN

SO

R

PJ3

JP

2

U7

CX7

TB2

AIN

GND

AUX

U4

T

SH

LD

R

TB

1

OUT IN

P1

P2

K1

K2

PJ2

PJ1JP1

VAV Z C O NTR O L L ER PY S 1 01 8 5 4 R EV .

��

AC

TU

AT

OR

EX

PA

NS

ION

NET

ADD

8

3216

24

1

74

HC

57

3N

PB

31

92

0P

S SW1

U1

EE

PR

OM

EP

RO

M

PJ4

AIR

FL

OW

SP

AC

E S

EN

SO

R

PJ3

JP2

U7

CX7

TB2

AIN

GND

AUX

U4

T

SH

LD

R

TB

1

OUT IN

P1

P2

K1

K2

PJ2

PJ1JP1

VAV Z C O NTR O L L ER PY S 1 01 8 5 4 R EV .

����

�������

��

� �

��

��

�

��

� �

��

��

�

Net

wor

kLo

op

VA

V/C

AV

Con

trol

ler

VA

V/Z

one

Con

trol

ler

VA

V/Z

one

Con

trol

ler

VA

V/Z

one

Con

trol

ler

VA

V/Z

one

Con

trol

ler

VA

V/Z

one

Con

trol

ler

VA

V/Z

one

Con

trol

ler

VA

V/Z

one

Con

trol

ler

VA

V/Z

one

Con

trol

ler

VA

V/Z

one

Con

trol

ler

VA

V/Z

one

Con

trol

ler

VA

V/Z

one

Con

trol

ler

VA

V/Z

one

Con

trol

ler

Ligh

ting

Con

trol

ler

GP

C C

ontr

olle

r

MU

A C

ontr

olle

r

Rem

ote

Link

(Mod

em -

Opt

iona

l)

Per

sona

l Com

pute

r(O

ptio

nal)

Com

mLi

nk

To T

elep

hone

Wal

l Out

let

Mod

ular

Ser

vice

Tool

Net

wor

kLo

op

Mod

ular

Pol

ling

Dev

ice

(Onl

y R

equi

red

For

Zon

ed S

yste

ms)

Mod

ular

Sys

tem

Man

ager

To N

ext M

iniL

ink

On

Net

wor

k Lo

op

To O

ther

HV

AC

Uni

t C

ontr

olle

rs.

A M

axim

um O

f 58

Con

trol

lers

Can

Be

Inte

rcon

nect

ed O

n E

ach

Loca

l Loo

p

Min

iLin

k

Min

iLin

k

Pow

er/C

omm

Boa

rd

Loca

l Loo

p

AL

AR

M

CO

MM

UN

ICAT

ION

S

WA

TTM

AST

ER

CO

NTR

OL

S IN

C.

Orion Systems 29

Zoning Design Guide

Application Notes:

Zoning Large UnitsZoning systems work very well for HVAC units up to40 tons. It is reccommended that HVAC units largerthan 40 tons should be designed as true VAV systemsdue to the large number of zones involved. When usingHVAC units that are 25 to 40 tons, for zoning applica-tions, several rules must be considered to prohibit po-tential problems. If

Because of the larger air flow capacities of these units,great care must be taken in sizing zone and bypass damp-ers.

Use these guidelines to help keep you out of trouble.

• Always specify that the unit is equipped withhot gas bypass on the first stage of cooling.

• Always use a VFD instead of using a bypassdamper for controlling duct pressure

• The unit should be equipped with the maxi-mum number of heating and cooling stagesavailable.

• Avoid large zones served by a single damper.Try to break the larger zones up into multiplezones.

• Large units should always have a minimumof 6 zones due to the high air flow capacities.On larger tonnage units, the more zones thebetter

• To prevent excessive noise in the system,zone damper total minimum airflow settingsshould be equal to or preferably greater than30% of the units rated CFM.

As an added precaution, we recommend a high ductstatic safety switch be installed (Dwyer Model 1900-5-MR or equal) to prevent over pressurization of theductwork.

30 Orion Systems

Zoning Design Guide

Appendix

Figure 1-16: Transformer And Wire Sizing Considerations

C O N T R O L S

FILENAME

DATE: B. CREWS

DESCRIPTION:PAGE

DRAWN BY:

Wire & Transformer Sizing

JOB NAME

11/08/01

ORIONWIRSIZ1.CDR

Orion

24VAC Power - Transformer & Wire Sizing Considerations for Devices Without Modular Connectors

Component Power Requirements

120 / 24VAC

120 / 24VAC

Distance A to B cannot exceed 57.80 Ft. Distance from A to B cannot exceed 115.60 Ft.Distance from A to C cannot exceed 115.60 Ft.

Distance from A to B cannot exceed 230.40 Ft.Distance from A to C cannot exceed Ft.Distance from A to D cannot exceed Ft.Distance from A to E cannot exceed Ft.

230.40230.40230.40

120 / 24VAC

Some installers like to use one large 24VAC transformer to power several devices. This is allowable as long as polarity is maintained to each deviceon the transformer circuit.

Usingseparate transformers also allows redundancy in case of a transformer failure. Instead of having 8 controllers inoperative because of a malfunctioningtransformer you have only 1 controller off line. If the installer does decide to use a large transformer to supply power to several devices, the followingtransformer and wire sizing information is presented to help the installer correctly supply 24VAC power to the devices.

Following is a typical example to help the installer to correctly evaluate transformer and wiring designs.

Each -GPC Controller requires 8 VA @ 24VAC power. In the examples below we have a total of 8 GPC Controllers.

8 Zone Controllers @ 8VA each................ 8 x 8VA = 64VA.

The above calculation determines that our transformer will need to be sized for a minimum of 64VA if we are to use one transformer to power all thecontrollers.

Next we must determine the maximum length of run allowable for the wire gauge we wish to use in the installation. Each wire gauge below has avoltage drop per foot value we use to calculate total voltage drop.

18ga wire.................................0.00054 = voltage drop per 1’ length of wire16ga wire.................................0.00034 = voltage drop per 1’ length of wire14ga wire.................................0.00021 = voltage drop per 1’ length of wire

For our example we will use 18 gauge wire. WattMaster recommends 18 gauge as a minimum wire size for all power wiring.

Next use the voltage drop per foot value for 18 gauge wire from the list above and multiply by the total VA load of the 8 controllers to be installed.

0.00054 (Voltage drop per foot for 18 gauge wire) x 64VA controller load = Volts/Ft.

WattMaster controllers will operate efficiently with a voltage drop no greater than 2 Volts. Divide the total allowable voltage drop of 2 Volts by thenumber you arrived at above and you have the maximum number of feet you can run the 18 gauge wire with an 75 VA transformer with no more than a2 Volt drop at the farthest controller from the transformer..

2 (Volts total allowable voltage drop)= 57.80

0.0346 (Voltage drop per 1 ft. @ 64VA load)

Parallel circuiting of the wiring instead of wiring all 8 controllers in series allows for longer wire runs to be used with the same size wire (as shown inour examples below).

Warning: If polarity is not maintained, severe damage to the devices may result. WattMaster Controls recommendsusing a separate transformer for each device in order to eliminate the potential for damaging controllers due to incorrect polarity.

0.0346

feet

It is often necessary for the installer to calculate and weigh the cost and installation advantages and disadvantages of wire size,transformer size, multiple transformers, circuiting, etc., when laying out an installation. No matter what layout scheme is decided upon, it is mandatorythat the farthest controller on the circuit is supplied with a minimum of 22 Volts.

GPC Controller .........................8VAVAV/CAV Controller ..................8VA

MUA Controller.........................8VA

HCCO Controller ......................8VA

GPC-17 Controller ....................10VA

Lighting Panel Controller ..........10VA

MiniLink....................................4VAOptimal Start Scheduler ...........10VA

A

A

A

B C D EBB C

1 of 2

Orion Systems 31

Zoning Design Guide

Figure 1-17: Transformer And Wire Sizing Considerations

C O N T R O L S

FILENAME

DATE: B. CREWS

DESCRIPTION:PAGE

DRAWN BY:

Wire & Transformer Sizing

JOB NAME

11/08/01

ORIONWIRSIZ1.CDR

Orion2 of 22 of 2

24VAC Power - Transformer & Wire Sizing Considerations for Devices With Modular Connectors

Modular devices include the VAV/Zone Controller, ModularSystem Manager & Modular Polling Device. When sizingtransformers for the devices it is important to design yourlayout so that the fewest number of Power/Comm distributionboards and the least number of transformers can be used.The polarity problem discussed in regards to other devicesthat do not have modular connections is not an issue with themodular devices as they cannot be connected with reversedpolarity because of the modular board connectors and cable.Also the prefabricated cable is always 16 gauge. Wire sizeselection is therefore not an issue with the modular devices.However, the same minimum voltage rules apply to modulardevices as with other non-modular devices. In order tosimplify wiring design and layout with modular devices thefollowing rules apply:

Power/Comm Board maximum transformer size = 100VA.This is due to the board circuitry and fusing. Each modulardevice is to be calculated at 6VA. This allows for a maximumof 16 devices per Power/Commboard. If more than 16devices are required, multiple Power/Comm boards must beused.

No more than 6 modular devices allowed per branch circuit.(The Power/Comm board has a total of 4 branch circuits)

The longest total run per branch circuit is 240 Ft. This is dueto voltage drop on the prefabricated cable.

Below are some examples of transformer sizing and branchcircuit design.

120 / 24VAC

120 / 24VAC

120 / 24VAC

120 / 24VAC

80 VATransformer

MinimumSee WarningNote Below

40 VATransformer

MinimumSee WarningNote Below

100 VATransformer

MinimumSee WarningNote Below

75 VATransformer

MinimumSee WarningNote Below

Power/CommBoard

Power/CommBoard

Power/CommBoard

Power/CommBoard

Total length of all modular cables used on each branch ( A to B) cannot exceed 240 Ft.

Total length of all modular cables used on each branch ( A to B) cannot exceed 240 Ft.

A

A

A

A

12 Devices At 6 VA = 72 VAUse 75 VA Transformer

Warning!DO NOT GROUND THE 24V TRANSFORMER THAT ISTO BE USED WITH THE POWER/COMM BOARDS.Grounding Of The Transformer Will Damage ThePower/Comm Board And All Boards Connected To It.

6 Devices At 6 VA = 36 VAUse 40 VA Transformer

16 Devices At 6 VA = 96 VAUse 100 VA Transformer

13 Devices At 6 VA = 78 VAUse 80 VA Transformer

6 Devices Maximum Per Branch Circuit

6 Devices Maximum Per Branch Circuit

Form: OR-SYS-ZDG-01B Printed in the USA March 2002All rights reserved Copyright 2002

WattMaster Controls Inc. • 8500 NW River Park Drive • Parkville, Mo. • 64152

Phone (816) 505-1100 www.orioncontrols.com Fax (816) 505-1101