series 21/31 installation instructions and field …

SERIES 21/31 INSTALLATION INSTRUCTIONSand field service check list

BULLETIN MI2045-01/04REPLACED MI1081

SERIES 21 Amplifiers (single furnace):A1010A - use with TD121A1010B - high fire ignition - use with TD121A1010E - integral temp. selectorA1010F - integral temp. selector and high fire ignition

SERIES 31 Amplifiers (multiple furnace):A1011A - use with TD121A1011B - high fire ignition - use with TD121A1011E - integral temp. selectorA1011F - integral temp. selector and high fire ignition

Modulator-Regulator Valves:MR410 - (3/8" and 1/2" pipe size)MR510 - (1/2" and 3/4" pipe size)MR610 - (3/4" and 1" pipe size)

Remote Temperature Selectors:TD121 - (55o to 90o F)TD121A - (80o to 130o F)TD121B - (120o to 170o F)TD121C - (160o to 210o F)TD121D - (200o to 250o F)TD121E - (100o to 250o F)TD121F - (40o to 80o F)NOTE: Remote Selector and Discharge Temperature Sensormust have same temperature range to be compatible.Optional: ETD-1 enclosure, EFP-1 cover plate only - no enclosure

Discharge Temperature Sensors: use with Mixing TubeTS121 - (55o to 90o F)TS121A - (80o to 130o F)TS121B - (120o to 170o F)TS121C - (160o to 210o F)TS121D - (200o to 250o F)TS121E - (100o to 250o F)TS121F - (40o to 80o F)

Mixing Tubes: used with SensorsMT1-9 or 2-9 (9" length)MT1-12 or 2-12 (12" length)MT1-23 or 2-23 (23" length)MT1-28 or 2-28 (28" length)MT1-57 (57" length)

Optional:

Inlet Air Sensors: use with Mixing TubeTS10765A - (8:1 ratio)TS10765B - (5:1 ratio)TS10765C - (3.5:1 ratio)

Override Stat: use with TD121 onlyT115 - (40o to 90o F)

Override Stat

A1010 Amplifier A1011 Amplifier

System Components

Table of ContentsPage 2 Introduction and DimensionsPage 3 Specifications

Installation of ComponentsPage 4 & 5 Field Service ChecklistPage 6 Preliminary Circuit Analysis

Performance CheckExtended High-Fire Ignition

Page 7 Wiring DiagramsPage 8 Temperature Calibration

Valve Adjustments

ValveRemote Temperature Selector

Sensor and MixingTube

3.00�(76.2)

1.50�(38.1)

2.96

1.25

1-9/164-3/16

1.503.00 REF

MOUNTING HOLE�4-PLACES

2.56

6.00�(152.4)

2.00�(50.8)

Length (See page1)

MOUNTING HOLES

1.411.69

4.69

�

3.46�3.25

2.50�REF.�

4-3/16�

1.00 DIA.

#10-16 x 1/2 LG.�BINDING HD. SHEETMETAL SCR.2-REQ'D.

3.38�(85.9)�

1.69�(42.9)�

2.60�(66.0)

9.50�(241.3)

1.25�(31.8)

RUBBER GROMMET(BOTH ENDS)5/8"I.D.(15.9)

2.75�(69.9)

2.75�(69.9)

8.00�(203.2)

.75

(19.1)

1.75�(44.5)

2.56�(65.1)

MOUNTING HOLES�2 REQ'D.5.50�

(139.7)

4.19�(106.4)

4.19�(106.4)

1.88�(47.6)

#10-16 x 1/2 LG.BINDING HD. SHEETMETAL SCR.2-REQ'D.

T115

A1010

A1011

TD121

MIXING TUBES

Selectra SERIES 21/31 electronic gas flame modulation systems are designed primarily for make-up air heating, as components of indirect fired units with atmospheric burners. All fuel gases are compatible.

The SERIES 21 is designed for single function operation, and the SERIES 31 is capable of handling up to four furnances. They may be field installed on existing equipment or specified for new equipment installation.

The systems utilize Modulator-Regulator valves. Amplifiers are available for high-fire ignition with

integral or remote temperature selection. A discharge air temperature sensor is mounted within a mixing tube housing. Optionally, a room override thermostat provides space temperature control by raising the discharge air temperature to a pre-selected point - when used in conjuction with the remote temperature selector. Also optional, an inlet air sensor (and mixing tube) provides inverse change in discharge air for each degree change in inlet air - when installed in a convenient duct location upstream of the burner.

Introduction and Dimensions

2

SpecificationsGases: All fuel gases.

Pressure Limits:Inlet (maximum) MR410 / 510 / 610.....1 psi / 69 mbar

Outlet (maximum fire)standard spring*.....3.0" to 5.0" w.c. / 7 to 12 mbarH - models.....7.5" to 12" w.c. / 19 to 30 mbarMax. set point not to exceed 10" w.c. above min.set point

Outlet (minimum fire)MR*10B10L standard spring*.....0.2" to 1.2" w.c. /.5 to 3 mbarMR*10B10L-1 spring*.....1" to 2.8" w.c. / 2.5 to 7 mbar* other spring ranges available - consult factory

Power Requirements:Single Furnace.....24V AC, 40VA capacityMultiple Furnace.....24V AC, 100VA capacityNOTE: Transformer secondary must not be groundedin any portion of the circuit external to a Maxitrolamplifier. If existing transformer is grounded, aseparate isolated transformer must be used. Electricalinterference may effect performance and/or damageequipment.

Temperature Control Range:Standard.....55o to 90o FOptional ranges to.....250o F

Ambient Limits: -30o to 125o F / -34o to 52o C

Remote Selector: Install in control cabinet or other chosenlocation. Remove cover and wire as shown in diagram,page 7 - reassemble.

Room Override Thermostat: Place in heated area tosense average room temperature, not in direct path ofdischarge air stream. Use only with TD121 RemoteTemperature Selector. Wire as shown in diagram, page 7.

Note: For systems using up to four automatic gas valveswith 0.8 amp maximum current each, a 100VA transformerwill be adequate.

In the event that an automatic valve's current exceeds 0.8amps, it would be advisable to wire according to the'Independent Power Supply' diagram, page 7. Thetransformer for the modulating power - terminals 8 and 9 -should be 40VA, and the automatic valve transformershould be capable of handling required loads up to 3.5 ampsmaximum. If exceeding 3.5 amps, it will be necessary tooperate an auxiliary relay with contact rating sufficient tohandle the automatic valves.

Wiring Run: Control wires connected to the Override Stat,Discharge Air Sensor, or Remote Temperature Selectormust not be run close to or inside conduit with power orignition wires. Doing so may cause the unit to functionerratically or may destroy the amplifier. If shielded wiresare used, shield must be insulated and grounded at theamplifier location only.

Amplifier: Slide or snap out circuit board from amplifierbase. Mount base with two screws in chosen locationprotected from weather or contaminated atmosphere.Amplifier is ready for wiring when circuit board is replacedon base - protective cover need not be removed.

Discharge Temperature Sensor (in Mixing Tube): Cuthole in air duct - install several feet from heat exchanger toavoid thermal radiation effects. Locate in discharge airstream. Remove cover and wire as shown in diagram, page7 - reassemble.

Installation of Components

Valve: The MR valve must be in upright position, in a horizontal run of pipe only, with pilot gas supply upstream.

If diaphragm type automatic gasvalve is used with separateregulator, install MR valvedownstream from diaphragm gasvalve. Retain regulator in manifoldand adjust 2 or 3 turns tocompensate for pressure drop ofMR valve.

If full combination control isused, install MR valvedownstream. Adjust regulatorin combination control 2 or 3turns to compensate forpressure drop at MR valve.

If solenoid type automatic gasvalve is used with separateregulator, replace regulator withthe MR valve.

GASFLOW

REG MR

to burners

DIAPHRAGMVALVE

to burners

MRCONTROLGAS

FLOWMR

SOLVALVE

GASFLOW

to burners

COMBINATION

3

1.Fa

ulty

aut

omat

ic c

ontro

l val

ve.

2.In

stal

latio

n w

iring

err

or.

3.A

mpl

ifier

is fa

ulty

.

1.R

emov

e w

ire fr

om v

alve

, if v

alve

doe

s no

t clo

se v

alve

is fa

ulty

.

2.R

emov

e w

ire fr

om a

mpl

ifier

term

inal

10

or 1

1. If

val

ve re

mai

ns o

pen,

che

ck fo

r mis

wiri

ng.

3.If

AC

vol

tage

will

not

dro

p at

term

inal

s 8

and

11 -

whe

n D

C v

olta

ge a

t ter

min

als

1 an

d 2

isab

ove

20V

DC

- am

plifi

er is

faul

ty. I

f spa

ce te

mpe

ratu

re is

less

than

60°

or g

reat

er th

an85

°F (

< 16

° or >

29°

C),

see

Pre

limin

ary

Circ

uit A

naly

sis,

pag

e 6.

1.R

epla

ce a

utom

atic

con

trol v

alve

.

2.C

orre

ct w

iring

.

3.R

epla

ce a

mpl

ifier

.

4.R

ead

volta

ge a

cros

s va

lve

term

inal

s. If

24

V A

C, v

alve

is fa

ulty

.

5.R

ead

volta

ge a

cros

s te

rmin

als

8 an

d 11

on

ampl

ifier

. If 2

4 V

AC

, che

ck fo

r ope

nci

rcui

t to

auto

mat

ic v

alve

. If s

pace

tem

pera

ture

is le

ss th

an 6

0° o

r gre

ater

than

85°

F(<

16° o

r >29

°C),

see

Pre

limin

ary

circ

uit A

naly

sis,

pag

e 6.

6.

If A

C v

olta

ge re

adin

g re

mai

ns z

ero

- whe

n D

C v

olta

ge a

t ter

min

als

1 an

d 2

is b

elow

14 V

DC

-am

plifi

er is

faul

ty. I

f spa

ce te

mpe

ratu

re is

less

than

60°

or g

reat

er th

an85

°F (<

16° o

r >29

°C),

see

Pre

limin

ary

Circ

uit A

naly

sis,

pag

e 6.

4.R

epla

ce a

utom

atic

con

trol v

alve

.

5.C

orre

ct w

iring

.

6.R

epla

ce a

mpl

ifier

.

7.P

ower

sup

ply

mus

t be

24 V

AC

.

8.In

stal

l pro

perly

.

SY

MP

TOM

PO

SS

IBLE

CA

US

EFI

ELD

TE

ST

RE

ME

DY

Fiel

d S

ervi

ce C

heck

list

4.Fa

ulty

aut

omat

ic c

ontro

l val

ve.

5.O

pen

wire

to a

utom

atic

val

ve.

6.A

mpl

ifier

is fa

ulty

.

7.Fa

ulty

pow

er s

uppl

y.

8.M

R v

alve

inst

alle

d ba

ckw

ards

.

7.R

ead

volta

ge a

t am

plifi

er te

rmin

als

8 an

d 14

(24

V A

C).

8.A

rrow

on

MR

val

ve s

houl

d po

int i

n di

rect

ion

of g

as fl

ow.

9.R

oom

Ove

rrid

e Th

erm

osta

t, if

used

, cal

lsfo

r hea

t.

10.O

pen

circ

uit i

n se

nsin

g an

d se

tting

circ

uit.

9.R

emov

e T1

15 w

ires

from

am

plifi

er te

rmin

als

3 an

d 14

.

10.D

isco

nnec

t and

mea

sure

acr

oss

wire

s co

nnec

ted

to a

mpl

ifier

term

inal

s 3

and

4 (A

1010

mod

els)

. Sho

uld

read

bet

wee

n 8,

000

and

12,0

00 o

hms.

9.If

prop

er o

pera

tion

is o

btai

ned,

che

ck th

e th

erm

osta

t wiri

ng fo

r sho

rts.

Rot

ate

ther

mos

tat d

ial a

bove

and

bel

ow ro

om te

mpe

ratu

re to

pro

veth

erm

osta

t fun

ctio

n.

10.I

f abo

ve 1

2,00

0 oh

ms,

che

ck c

ircui

t for

ope

n or

loos

e w

ires.

11.C

heck

wiri

ng fo

r def

ects

.

12.P

lung

er s

houl

d be

sm

ooth

, cle

an, a

nd o

pera

te fr

eely

in s

olen

oid

slee

ve.

13.M

easu

re v

olta

ge a

cros

s M

R v

alve

.

11.

Ope

n ci

rcui

t in

wiri

ng to

MR

val

ve.

12.

Plu

nger

jam

med

or i

nsta

lled

upsi

de d

own.

13.

Faul

ty M

R v

alve

.

11.R

epla

ce w

iring

if n

eces

sary

.

12.C

lean

or r

epla

ce p

lung

er.

13.I

f mod

ulat

ing

volta

ges

are

obta

ined

but

no

gas

mod

ulat

ion,

MR

val

veis

faul

ty. R

epla

ce if

nec

essa

ry.

14.D

isco

nnec

t and

mea

sure

acr

oss

wire

s co

nnec

ted

to a

mpl

ifier

term

inal

s 3

and

4 (A

1010

mod

els)

. Sho

uld

read

bet

wee

n 8,

000

and

12,0

00 o

hms.

14. S

hort

circ

uit i

n se

nsin

g an

d se

ttlin

g ci

rcui

t.14

.If b

elow

8,0

00 o

hms,

che

ck c

ircui

t for

sho

rts o

rm

isw

iring

.

15.H

eat l

oad

requ

ires

low

fire

onl

y.

16.P

lung

er a

nd/o

r max

imum

spr

ing

mis

sing

.

17.J

amm

ed p

lung

er

18.O

ther

val

ve fa

ults

.

19.I

nade

quat

e su

pply

pre

ssur

e.

15.I

ncre

ase

tem

pera

ture

setti

ng 1

0 de

gree

s.

16.C

heck

for p

arts

(see

'Val

ve A

djus

tmen

ts' fi

gure

, pag

e 8)

.

17.E

xam

ine.

Plu

nger

sho

uld

be c

lean

, sm

ooth

, and

ope

rate

free

ly in

sol

enoi

d sl

eeve

.

18.R

emov

e w

ire fr

om M

R v

alve

.

19.R

emov

e sp

ring

5 fro

m M

R v

alve

(see

val

ve fi

gure

, pag

e 8)

, pus

h do

wn

on p

lung

er.

Insu

ffici

ent m

anifo

ld p

ress

ure

with

furn

ace

oper

atin

g in

dica

tes

supp

ly is

too

low

.

15.I

f hea

ter g

oes

to h

igh

fire,

sys

tem

is w

orki

ng c

orre

ctly

.

16.I

nsta

ll cor

rect

par

ts.

17.C

lean

, or r

epla

ce p

lung

er if

nec

essa

ry.

18.I

f MR

val

ve re

mai

ns o

n lo

w fi

re, v

alve

may

be

faul

ty.

Che

ck it

em 1

9 be

low

, the

n re

plac

e va

lve

if ne

cess

ary.

19.C

heck

for o

bstru

ctio

n in

gas

pip

e ah

ead

of c

ontro

ls.

Incr

ease

gas

pre

ssur

e if

poss

ible

.

20.R

ecal

ibra

te p

er 'T

empe

ratu

re C

alib

ratio

n' p

roce

dure

.20

.Cal

ibra

tion.

20.C

heck

sea

l on

calib

ratio

n po

tent

iom

eter

.

21. D

irty

or s

ticki

ng p

lung

er.

22. I

nter

mitt

ent s

horti

ng in

wiri

ng.

23. F

aulty

am

plifi

er.

21.C

lean

, or r

epla

ce p

lung

er if

nec

essa

ry.

22.C

orre

ct w

iring

.

23.I

f err

atic

or p

ulsa

ting

DC

vol

tage

is o

bser

ved

and

wiri

ngsh

ows

no d

efec

ts, r

epla

ce a

mpl

ifier

. If e

rrat

ic o

rpu

lsat

ing

volta

ge co

ntin

ues,

cont

act M

axitr

ol.

21.E

xam

ine.

Plu

nger

sho

uld

be c

lean

, sm

ooth

, and

ope

rate

free

ly in

sol

enoi

d sl

eeve

.

22.I

nspe

ct w

iring

.

23.O

bser

ve D

C v

olta

ge a

cros

s am

plifi

er te

rmin

als

1 an

d 2.

*Con

trol

cir

cuits

ext

erna

l to

the

Ser

ies

21 a

nd 3

1 ca

n ca

use

burn

er m

alfu

nctio

n. A

lway

s ch

eck

man

ual v

alve

to b

e ce

rtai

n ga

s is

on,

and

che

ck li

mit

cont

rols

for n

orm

al o

pera

tion.

A.

B. C.

D.

Aut

omat

ic c

ontr

ol v

alve

will

not

clo

sede

spite

full

rang

e of

mod

ulat

ing

volta

geat

term

inal

s 1

and

2.

Aut

omat

ic c

ontr

ol v

alve

won

’t op

ende

spite

full

rang

e of

mod

ulat

ing

volta

ge a

t ter

min

als

1 an

d 2.

No

gas

flow

.

Con

tinuo

us h

igh

fire.

E. F.

Con

tinuo

us h

igh

fire

but a

utom

atic

valv

e cy

cles

.

Furn

ace

won

’t ac

tivat

e du

e to

con

stan

thi

gh m

odul

atin

vol

tage

(abo

ve 1

7 V

DC

).

G.

H.

Con

tinuo

us lo

w o

r med

ium

fire

, but

auto

mat

ic v

alve

cyc

les

corr

ectly

.

Inco

rrec

t dis

char

ge a

ir te

mpe

ratu

re.

I.Er

ratic

or s

ever

ly p

ulsa

ting

flam

e.

Automatic Valve Function:After the electronic modulation function is tested, a voltagereading must be taken across the automatic gas valve.These voltage readings will be approximately 24 V AC withthe temperature selection knob at maximum setting, zerovolts AC with the selector at minimum setting. The relayswitching action should occur when the modulating voltageis between 15 and 19V DC.

If these voltage readings are observed as noted, it is provedthat the amplifier and temperature selector are operatingproperly.

After testing, remove the resistor and reconnect thedischarge air sensor.

Preliminary Circuit AnalysisIn order to diagnose the cause of problems in this system itis necessary to determine certain values. It is helpful tohave an AC and DC voltmeter and an ohmmeter capable ofreading 0 to 15,000 ohms. For ease in trouble shooting, itis necessary to rewire the system, replacing the dischargeair sensor with a 4500 ohm (4300 ohm + 200 ohm), 1/2 watttest resistor.

Modulating Function Test:Connect a DC voltmeter to amplifier terminals 1 and 2. Ifmore convenient, the meter may be attached to the MRvalve terminals. Rotate temperature selection knob tomaximum setting - the DC volts should read zero. Thevoltage should gradually increase to at least 20 volts whenthe temperature selector is slowly rotated to its minimum(generally over a 3° to 4° range).

With the modulator-regulator valve installed as instructed(voltages are approximate)...

Minimum fire is above 14 volts DC.Manifold pressure can be adjusted as folows:MR*10B10L Standard spring 0.2" to 1.2" w.c.(.5 to 3 mbar)MR*10B10L-1 spring 1" to 2.8" w.c.(2.5 to 7 mbar)Maximum fire is obtained at zero volts DC.Use manufacturer's pressure specifications when available.Maxitrol standard factory settings are 0.5" w.c. (1.25 mbar)minimum and 3.5" w.c. (8.75 mbar) maximum. H-1 models1.75" w.c. (4.35 mbar) minimum and 11" w.c. ( 27 mbar)maximum.

At Temperature Selector:1) Set the selector at least 10o higher than incoming air andallow discharge air temperature to stabilize. Discharge airtemperature should agree with temperature selector setting.2) Increase temperature setting by 5o to 10o. Heatermanifold pressure should immediately go to high fire.

Manifold pressure will decrease as the discharge airtemperature approaches the setting and will stabilize at thetemperature setting.3) Decrease temperature to the original setting. Burnershould immediately turn off. Then, as the discharge airtemperature decreases, the burner should ignite at low fire.The discharge air temperature should again stabilize at thetemperature setting. On amplifiers containing a high fireignition function, refer to Extended High-Fire Ignition sectionbelow.

If the preceding readings are not obtained:4) Recheck wiring to ensure system is consistent withappropriate wiring diagram.5) Check power source for 24 volts.6) Some automatic control valves require as much as 20seconds to open. In this case, check for 24VAC output atautomatic valve terminals.

Note: Depending on the Btu capacity of the heater and thetemperature rise, the discharge air temperature may becontrolled by a continuous modulated flame (hightemperature rises) or by on/off operation (low temperaturerises).

Performance Check

Extended High-Fire Ignition

On A1010B, A1010F, A1011B, and A1011F amplifiers, thehigh fire start duration is approximately five seconds. Toextend it from 5 seconds to approximately 25 seconds,remove 100K (brown-black-yellow-gold) resistor from boardas shown.

On furnaces equipped with slow opening automatic valves,it is recommended to make this modification.

Snip Off Resistor

5

Single Furnace Operation - Series 21

Preliminary Circuit Analysis

Multiple Furnace Operation - Series 31(MR valves and automatic gas valves wired in parallel as shown)

A1010AA1010B

(Series 21)

A1010EA1010F

(Series 21)

6

Temperature Calibration

Note: High Fire Adjustment should be checked whenever Low Fire Adjustment is changed.

Disconnect wire from amplifier terminal 3, remove cover plate (2).

(See bulletin MT2035 for additional M/MR valve information)

Valve Adjustments

1. TOP HOUSING2. COVER PLATE3. SEAL GASKET4. MAXIMUM ADJUSTMENT SCREW5. MAXIMUM ADJUSTMENT SPRING6. SOLENOID7. MINIMUM ADJUSTMENT SPRING8. PLUNGER9. MINIMUM ADJUSTMENT SCREW10. MINIMUM ADJUSTMENT SCREW STOP

21

9

6

5

3

4

8

7

10

If needed - amplifier potentiometer adjustment - for heatsensing with Discharge Temperature Sensor (TS121) :Install a thermometer or other temperature measuringdevice at a point adjacent to the tip of the TS121 DischargeAir Sensor. Set the temperature selector at least 15o abovethe existing outdoor air temperature. (Accurate calibrationcannot be made at temperature differentials of less than15o.)

Adjust calibrating potentiometer (A) until thermometerreading agrees with temperature setting. Note: Adjust (A)in small increments and allow time for the discharge airtemperature to stabilize after each adjustment.

High Fire Adjustments:A) Using maximum adjustment screw (4), set manifoldpressure to furnace manufacturer's specifications.B) Replace cover plate (2) on Modulator-Regulator valveand reconnect wire to amplifier terminal 3.

Low Fire Adjustments:A) Remove maximum adjusting screw (4), spring (5), andplunger (8). A small magnet is useful for this purpose.CAUTION - The plunger is a precision part. Handlecarefully to avoid marring or picking up grease and dirt. Donot lubricate.B) Using minimum adjusting screw (9), set manifoldpressure to furnace manufacturer's specifications.C) Replace plunger and spring retainer, spring, andmaximum adjusting screw in proper order.

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CAUTION: Operation of combustion equip-ment can be hazardous resulting in bodilyinjury or equipment damage. Each burnershould be supervised by a combustion safe-guard and only qualified personnel shouldinstall, make system adjustments and per-form any required service.

NOTICE: Maxitrol practices a policyof continuous improvement in the de-sign of its products. It reserves theright to change the specifcations atany time without prior notice.

ORDAN THERMAL PRODUCTS LTDCombustion Equipment & Controls for Industry

21 Amber St # 9, Markham Ontario Canada L3R 4Z3 Tel: (905) 475-9292 Fax: (905) 475-3286

www.ordanthermal.com






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series 21/31 installation instructions and field …

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