electronic controls system with variable air volume box

Electronic Controls System with Variable Air Volume Box

A thesis submitted to the Faculty of the Electrical & Computer Engineering Technology Program

of the University of Cincinnati

This document is a partial fulfillment of the requirements for the degree of

Bachelor of Science

in Electrical or Computer Engineering Technology at the College of Engineering & Applied Science

by

ANDREW LEMMON (EET) KYLE HURLESS (CET)

Bachelor of Science University of Cincinnati

May 2013

Faculty Advisor: Elvin Stepp

3060 Marshall Ave.

APT 204

Cincinnati, OH 45220

April 19, 2013

Professor Elvin Stepp

University of Cincinnati

College of Engineering & Applied Science

2600 Clifton Ave.

Cincinnati, OH 45221

Dear Professor Elvin Stepp:

Attached is our final report on the “Electronic Controls System with Variable Air Volume Box,”

which was requested by the ECET faculty.

This report covers all of the details that led to the completion of this project. This report will

include the problem, solution, credibility, and methodology. These sections will include the

design requirements, the procedure, testing, problems encountered, budget, timeline, analysis of

the solution. Any future recommendations that could help improve this project in the future will

be given as well. We will also explain how this system was implemented into the buildings at

Wright Patterson Air Force Base.

Throughout this project, we were advised not only by you, but also Professor James Everly,

Professor Max Rabiee, Professor Xuefu Zhou, and Wright Patterson Air Force Base Electrical

Industrial Controls Supervisors Forrest Dent and Danny Hall. These faculty members and

supervisors were very helpful in their wisdom of the design, both wiring and programming, the

implementation, and the documentation of the project. We appreciate your time and effort

reviewing this report. If you have any questions or comments please feel free to contact us.

Sincerely,

Andrew D. Lemmon

937-441-0802

[email protected]

Kyle J. Hurless

330-417-5004

[email protected]

mailto:[email protected]

mailto:[email protected]

ACKNOWLEDGEMENTS

We would like to thank many people for the help and support they provided during the

completion of our Senior Design Project.

Professor Elvin Stepp for the wisdom offered to us in the hardware and software design.

Professor Max Rabiee for getting us started in the right path on this project.

Professors Michael Hass, James Everly, Xuefu Zhou, and David Tashjian for the

education that made it all possible.

Our Family and Friends for the neglect that we showed them during this project.

Wright Patterson Air Force Base for the Parts and Supplies that helped us build this

project.

WPAFB Electrical Industrial Controls Shop for the wisdom that guided us to the

completion of this project.

WPAFB Front End for their help and our use of their MS1800 HVAC controls software.

University of Cincinnati for the other excellent instructors and facilities that made this

project possible.

Microsoft for their software that let us make all of the entries and reports for this project.

Electronic Controls System

With Variable Air Volume Box

Table of Contents

ABSTRACT……………………………………………………………………………………… 1

INTRODUCTION……………………………………………………………………………….. 1

Problem…………………………………………………………………………………... 4

Solution…………………………………………………………………………………... 4

Credibility………………………………………………………………………………... 4

Andrew Lemmon…………………………………………………………………. 4

Kyle Hurless……………………………………………………………………… 4

Goals and Methodology………………………………………………………………….. 5

Objectives………………………………………………………………………………… 5

DISCUSSION…………………………………………………………………………………….. 6

Concept…………………………………………………………………………………… 6

Design Criteria……………………………………………………………………………. 6

Convert the Pneumatic Controls System to Electronic Controls…………………. 6

Have the system connected to a centralized location ……………………………. 6

Design the panel to equipment specifications ……………………………………. 6

Easy to use………………………………………………………………………... 7

Easy to troubleshoot and repair…………………………………………………... 7

Expansion capable………………………………………………………………... 7

VAV linked to control panel…………………………………………………….... 7

VAV to follow same criteria as the control panel………………………………....7

TECHNICAL APPROACH……………………………………………………………………… 8

Air Handler Flow………………………………………………………………………… 8

Control Panel……………………………………………………………………………..10

Variable Air Volume Box……………………………………………………………….. 14

Linked or Separate Project………………………………………………………………. 17

BUDGET…………………………………………………………………………………………18

TIMELINE……………………………………………………………………………………… 20

PROBLEMS ENCOUNTERED………………………………………………………………... 21

Transformer Problem …………………………………………………………………... 21

Board Port Problem……………………………………………………………………... 21

Simulation Problem……………………………………………………………………... 21

Grounding Problem……………………………………………………………………... 21

Re-heat coil actuator Problem…………………………………………………………... 22

Actuator Signal Problem………………………………………………………………… 22

FUTURE RECOMMENDATIONS…………………………………………………………….. 22

Tech Expo Network……………………………………………………………………... 22

BACnet Conversion……………………………………………………………………... 22

Use new Siemens Control System………………………………………………………. 22

CONCLUSION………………………………………………………………………………….. 23

REFERENCES…………………………………………………………………………………...23

APPENDIX A…………………………………………………………………………………… 24

Network Programming………………………………………………………………….. 24

Smart II Control Fan Coil Board Network Programming Page 1………………. 24

Smart II Control Fan Coil Board Network Programming Page 2……………….. 25

Electronic Controls System

With Variable Air Volume Box

Smart II Control Fan Coil Board Sample Network for Auxiliary Board Expansion……………...25

APPENDIX B…………………………………………………………………………………… 26

Photographs………………………………………………………………………………26

Control Panel Photographs……………………………………………………….26

Simulation Panel for the AHU control panel ……………………………26

Top of control panel transformers and fuses……………………………. 26

120VAC input power to panel…………………………………………... 27

Temperature control valve for heating coil……………………………… 27

Control Panel Damper Actuator…………………………………………. 28

Control Panel Power Supply Board……………………………………... 28

Control Panel Smart II Fan Coil Board…………………………………. 29

Wiring Behind the Smart II Fan Coil Board…………………………….. 29

VAV Box Photographs………………………………………………………….. 30

Reheat Coil Actuator with Reheat Coil…………………………………. 30

Temperature Control Valve VAV Reheat Actuator……………………... 30

Thermostat for VAV box………………………………………………... 31

VAV box Damper Actuator……………………………………………... 31

VAV box Transformer from 120V to 24V……………………………… 32

Smart II VAV Control Board …………………………………………... 32

Wiring Behind Smart II VAV Control Board …………………………... 33

APPENDIX C…………………………………………………………………………………… 34

Data Sheets for the Actuators ……………………………………………………………34

Belimo ……………………………………………………………………………34

Siemens………………………………………………………………………….. 36

List of Illustraitions

Figure 1: Air Handler Unit (AHU) Panel………………………………………………………… 2

Figure 2: Variable Air Volume (VAV) Box……………………………………………………... 3

Figure 3: Air Handling Unit Flow Diagram……………………………………………………….8

Figure 4: Smart II Control Board Wiring Diagram………………………………………………10

Figure 5: Control Panel Interface………………………………………………………………... 11

Figure 6: Loop Diagram for Smart II Fan Coil Control Board………………………………….. 12

Figure 7: VAV Wiring Diagram………………………………………………………………… 14

Figure 8: VAV Box Loop Chart………………………………………………………………… 16

Table 1: Initial Budget……………………………………………………………………………18

Table 2: Final Budget……………………………………………………………………………. 19

Figure 9: Project Timeline………………………………………………………………………. 20

E l e c t r o n i c C o n t r o l s S y s t e m w i t h

V a r i a b l e A i r V o l u m e B o x P a g e | 1

Abstract

An electronic digital controls system using Staefa controls allows a more precise system

that will allow variable fan speeds on the air handler and better troubleshooting techniques. With

the digital system you do not have the issue of a compressor that if there is any kind of hole or

crack in the line it will not be able to hold pressure. Also you will have a large area to determine

where the leak is. With a digital system, the control systems network is routed back to a central

network center so that it will be able to tell the technicians what is wrong. This way they will

have the tools required to fix it, sometimes, even before anyone realizes that there is a problem.

The digital systems allow energy savings based on more precise set-points, variable supply fan

and return fan speeds, and better customer service. All of the problems encountered in this

experiment were overcome. These include wiring and programming problems.

Introduction

This report outlines the process involved in starting, conceptualizing, designing (both hardware

and software, and completing the Electronic Controls System with Variable Air Volume (VAV)

Box.

The Electronic Controls Air Handling Unit (AHU) panel, seen in figure 1 (Below), is a panel

that controls the functions of an air handler. This includes the dampers, actuators, coils, and

motors in the system. Many of these systems are currently run on pneumatics and we are

planning to convert this system to electronic because of the many benefits that it shows. The

main objective of using this panel is to take out the current pneumatic, air pressure based, system

and replace it with an electronic system which has a quicker reaction time to signals, has more

precise set-points, allows easier troubleshooting, allows variable supply and return fan speeds,

centralized network control, and has a great energy savings benefit. An electronic system makes

costs cheaper and allows an up to date database that allows the technicians to monitor these

systems based off of the values on the inputs and outputs in the network.



Figure1: Air Handler Unit (AHU) Panel

The system shown above has both an extensive hardware and software element to it. This

system uses the two boards shown at the bottom which are called SMART II boards. These

boards allow control based on programming and the wiring going to the analog inputs and

outputs, as well as the digital and proportional inputs and outputs. With the pneumatic systems

the panel is stand alone which means that the unit is in the building and there is no way to

monitor these units to see when there is a problem. The electronic systems allow a centralized

network which would allow technicians to have constant monitoring of the unit and also allow

them to know what was wrong with the unit so they can have it fixed, many times, before the

people in the building know that something is wrong. As you can see this is accomplished by the

2 SMART II boards, actuators, transformers, fuses, relays, and wiring blocks.



The second part of this project was the Variable Air Volume (VAV) box. This is the portion that

is used to provide air flow to a specific section of a room or a whole room depending of the size

of the room and the size of the box. The VAV box shown in figure 2 (below) is also being

converted to electronics to pneumatics because of many of the same reasons.

Figure 2: Variable Air Volume (VAV) Box

As you can see this is the VAV box portion of this project. The VAV box is a unit found above

the ceiling that is used to control the temperature and air flow going into the space. The VAV

box includes a SMART II board, a damper actuator, a re-heat coil actuator, a transformer

(simulation only), a temperature sensor, and an air flow sensor. All these components wired into

the board are used, along with the programming, to control the air flow going into the space.

This is the electronic VAV system. We are converting from the pneumatic system because of

many of the same reasons as converting the panel. The Pneumatic VAV systems have a problem

with the pneumatic tubing dry rotting, the volume controllers breaking the seals, and are very

unpredictable. Everything with pneumatics is done with a potentiometer from the VAV aspect

of this system. This does not give very precise set-points whereas the electronic system gives a

specific set-point for the flow and the temperature of the air. Also, the reason that the

transformer is for simulation purposes only is because when you convert the system over to an

electronic system is because 24VAC is run throughout the entire building and run to each of the

VAV boxes allowing it to have more space in the box.

The equipment for this project was provided by Wright Patterson Air Force Base and this project

was presented to us as a need to the base to help save money in costs both energy and technician

repair.



Problem

Currently many Air Handling Unit (AHU) systems and variable air volume (VAV) units are

working using pneumatics. The industrial controls systems using pneumatics, use pressure to

control dampers of the AHU and VAV systems and control the speed of the motors on the AHU

systems. The need is to convert these pneumatic systems over to Direct Digital Controllers or

Electronic Controls systems. The pneumatic systems cannot be monitored by a central location

and are not easily fixed. A common problem with these systems is water in the pneumatic tubing

which can rot out the diaphragms in the actuators. An electronic system would allow monitoring

of these units from an exterior location where many units are monitored and would also allow the

user to troubleshoot the systems from a location to determine what is wrong with the system. If

there is a problem with a pneumatic system we would not know until someone reported the

problem to us whereas with electronic systems we would know before the issue is called in. A

conversion to Electronic controls systems would allow a significant improvement upon lowering

energy cost as well as faster response times to failures with the equipment.

Solution

The objective for this project is to design an electronic controls system that can be used to

control these AHU and VAV systems. Using the technology and equipment provided by Wright

Patterson Air Force base as well as the knowledge obtained during co-op assignments, we were

able to design this electronic controls system based upon the features of these units. After this

project was completed the objective is to be able to have more precise control as well as

significant energy cost savings. This will also allow our technicians to know what the problem is

before they get to the job site and also allow the technicians to fix the problem sometimes before

the people working in the space even find that there is a problem. These electronic systems also

require fewer components because of this multi-purpose board.

Credibility:

Andrew Lemmon: Andrew Lemmon’s primary focus on this project was on the software design

and partial hardware design. In this project he had to take the specifications and parameters of

the equipment and the space of the building and build the hardware and software design around

these parameters. Over the past three years Andrew has worked at Wright Patterson Air Force

Base in Dayton, Ohio as an Electrical Industrial Controls Technician. The knowledge obtained

from this past 3 years has given him the wisdom and troubleshooting skills to work and build this

equipment. The job allowed him to troubleshoot and repair this equipment, as well as, see the

problems with this equipment and see what can be improved upon.

Kyle Hurless: Kyle Hurless’s primary focus on this project was on the hardware design and

implementation. He had to design the hardware around the specifications for the building and



then implement the design onto the Air Handler Unit Panel and the Variable Air Volume Box.

Over the past two years Kyle worked at AMK Services in Richmond, Kentucky as an Radio

Frequency Technician. Through this experience, he has learned to design and implement

hardware needed for this project.

Goals and Methodology

With this project we are going to design an AHU control panel using Staefa Controls System

products. This panel is going to consist of multiple relays, transformers, power supplies,

indicators, potentiometers, Actuators, temperature sensor, control boards etc. Because this

control panel is for an AHU we will not be able to bring the physical unit to the demonstration

due to the size of these units, however we will take a video of this equipment working in the

field. At the tech expo we will simulate status’s using indicators and simulate the actuators using

smaller versions of these actuators with the control panel that will be put into use after the

finishing of this project. All of this equipment is provided by wright Patterson AFB and they are

very excited about the completion of this project to bring continuous energy savings over the

years.

VAV boxes are used to control the air coming from the air handler that goes into a space. These

boxes fluctuate air using a damper and control the temperature of the air using an actuator

controlled reheat coil. Even though we won’t be able to run hot water through this coil to show

the heating of the air we will be able to simulate the valve opening to show how the water passes

through. There will be a smaller panel on the side of this box which will allow us to control this

VAV using the Electronic controls systems equipment. We do have a physical VAV box to wire

up for this experiment and are going to bring this addition to show at the tech expo. Kyle Hurless

will be working on the programming side because he specializes in programming and Andrew

Lemmon will do the control panel design and wiring because he specializes in HVAC controls

from co-op and electrical wiring from UC. All parts and equipment have been paid for and

provided by Wright Patterson Air force base.

Objectives

The remainder of this final report outlines in detail how this project was completed. This report

will show the design objectives, technical approach, budget, timeline, problems, and any future

recommendations that we have for this project.



Discussion

Concept

The Electronic Controls System with Variable Air Volume Box was presented to us as a need by

Wright Patterson Air Force Base. With the pneumatic systems that are currently implemented

there are many issues with the current systems. Andrew Lemmon is one of the Controls

technicians at Wright Patterson Air Force Base and he has seen firsthand the problems that you

run into using these pneumatic systems.

In these electronic systems the thought was to come up with something that was easier to

maintain and would grant great energy savings. That is exactly what an electronic controls

system was able to do. With the electronics you are able to maintain these systems because

when there is a problem the system sends an alarm through the network and it alerts the

technicians when and where the problem is and what the problem actually is. As an example, if

the low temp cut out switch is tripped the system will send an alarm stating that the system went

down on low temperature. Also the energy savings portion where you have more precise set-

points and you do not have a compressor running all of the time. The other portion of the energy

savings is that you do not have to run the air handlers fans 100% all of the time and you are able

to have a variable fan speed. When the fans are not running 100% they are not putting out as

much power which means that you save energy not running the full power.

Design Criteria

This is the design criteria for the Electronic controls project.

Convert the Pneumatic Controls system to electronic controls

This allows all of the advantages of having a controls system such as the energy savings.

Have the system connect to a centralized location

Having the controls equipment hooked up to a centralized location allows monitoring of the

systems and also allows the monitors to tell the technicians when there are issues with equipment

and exactly where and what they need to fix.

Design the panel to the equipment specifications

The equipment that is currently in the room such as the fans and the dampers will remain the

same. However, the actuators and sensors will have to be switched out. The electronic system

will allow the fans to run at a lower speed with a lower current when needed. Electronic

actuators will allow the dampers to be controlled by electronics instead of air pressure.



Easy to use

You should be able to easily connect to this equipment on site or at a central network location

and change the programming or change set points on the equipment.

Easy to troubleshoot and repair

Equipment should be very easy to replace when needed. Also troubleshooting is made very easy

by working with this equipment using the hand tool, which is the electronic controls hand

programming device from staefa.

Expansion capable

We added an extra board onto this panel so that way we could add any other pieces of equipment

to this system such as a chiller or hot water boiler.

VAV must be linked to the Control Panel

VAV is linked through the network back to the panel so that way we could see how much

pressure is going through the building and whether to back off or add to the airflow by slowing

down or speeding up the supply fan.

VAV to follow same criteria as for the control panel.

The VAV uses the same box as before but we add an electronic hot water valve actuator and

damper actuator. We do this because of the dry rotted volume controller. This allows it to work

using electronic controls equipment. We also add on a pressure sensor and a supply air sensor.



Technical Approach:

The technical approach taken during the design, analysis, and testing of the Electronic Controls

system with variable air volume box was very in-depth and had multiple parts to it. The custom

solutions engineered into the systems are discussed in detail below. This will show the

programming and wiring schematics of the whole system.

Air Handler Flow

The control panel was the main part of this project. This is actually what sends all of the

actuators and the motors the command to run. Figure 3 (below) shows the flow for the air

handling unit.

Figure 3: Air Handling Unit Flow Diagram

An air handling system, like many systems, works in a cycle. What most people know is that air

goes in and air comes out. There are so many things that happen between these two points that

many people do not understand. There is always a minimum of at least 10% on any unit for

outside air. You must always have this because after so much time of recycling air people tend

to get sick. This is why we have the exhaust air damper. We cannot send air in and never let any

out. The unit will over pressurize and then will start blowing the doors open. One of the

components controlled by this panel is this outside air damper. The return fan is used to pull the



air from the space and push it into the air handling unit. This enable is part of the control system

and the speed at which this fan runs is also controlled by this control panel. The air that does not

get exhausted follows the flow down toward the next section of the flow chart.

The next section of this flow chart is the mixed air. The term mixed air comes from mixing the

return air and the outside air, as seen in figure 3 above. The amount of outside air is a damper

that is controlled by an actuator that gets its signal also from the control panel. After the air is

mixed it flows through the heating and cooling coils. The heating and cooling coils are also

controlled by an actuator. The actuator controls the valves that send hot and cool water to each

of the coils so that way they can change the temperature of the air. The air is then sent to the

supply fan which pushes all of this air back into the space. There are also Low temperature cut

out and high temperature cut out switches on these systems. These are used to where if there is a

malfunction and the air is too hot or too cold the switches are tripped and the system is shut

down. All of these things are controlled by the control panel which make it such an important

part of these HVAC systems.



Control Panel

As stated above the control panel plays a key part of this project and HVAC systems

everywhere. The wiring of this panel plays a crucial part of this system. The wiring diagrams

are shown in figure 4 (below) in the Smart II control board wiring diagram.

Figure 4: Smart II Control Board Wiring Diagram

Figure 4 (above) shows the wiring diagram going to the Smart II fan coil control boards on the

control panel. These control boards are what does the calculations to determine how open or

closed the dampers and valves need to be and also how fast the supply and return fans need to

run. One of the main features on these boards is that you can wire in a switch that is used for

changeover. Changeover allows you to change how the system runs during the seasons. The

two seasons that you normally would change for would be the summer and winter seasons.

There are also the low temperature and high temperature cut out options. With the Low Temp

cut out the system trips the switch shutting down the air handler. It does this because if the air

handler is running during freezing temperatures, you risk breaking your motor. The high temp

cutout is the same concept however it shuts the unit down when temperatures of air are over 90

degrees because something is wrong with the equipment. The temperature sensors for the supply

air and mixed air are also wired into this board. It reads a 4-20mA signal and converts the



resistance from this signal over to a temperature in the board. This was an issue at Tech expo for

simulation purposes and will be further explained in the problems section of this document. The

supply and mixed air sensors are used to tell the control board what it needs to do whether it is

cooling or heating the air.

Next is the wiring diagram for the Control board itself and also the wiring to the starters of the

supply and return fans. We show this in figure 5 (below).

Figure 5: Control Panel Interface

Figure 5 above shows the control panel interface with the system. In this diagram, you see how

the wiring to the specific components is attached through the transformer and is sent through the

different fuses and switches to the relays. Ultimately, the relays being energized are what makes

the system work. An example of this would be if the high or low temp cutout relays are not

energized the system shuts down or if it is not running will not start until a technician sees to the

unit. You can see in the left the diagram for the wiring of the return and the supply fan starter.

From what I explained earlier you can see how with the relays not being energized the system

will shut down.



The next part in this document will be the loop diagrams we designed to do the programming for

the Smart II fan coil boards. Figure 6 (below) shows the loop diagram that we designed for this

control board.

Figure 6: Loop Diagram for Smart II fan coil control board

The loop chart, shown in figure 6, is what we used to design this systems programming. We

thought that this would be the easiest way to design a good program with showing all of the

inputs and outputs whether they were digital, analog, or proportional. We used this to do both

the local and network programming. The hand tool was what we used to program at the local

level for this experiment. Starting with the left side at analog input 0 (AI-0) we have the room

temperature. The room temperature sensor is what tells the system whether it is to warm, to

cold, or just right in the space. This tells the system whether it needs to engage the cooling or

heating coils or just keep the current settings. The second analog input (AI-1) is the set-point

adjust for the room thermostat. The board itself is set to whatever temperature we want to keep



the space temperature at. Usually, this is 72-76 degrees. However, the thermostats offer a +4 -4

option so that way they can lower the temperature or raise the temperature 4 degrees. The third

analog input is actually a spare in case we ever want to add on to the system. The next input (AI-

3) is the input that tells us whether or not the supply fan is on or off. The next three inputs are

for the supply air, mixed air, and return air which I explained these 3 types before in the paper.

After this we go to the digital outputs. We have 3 start/stops which are for the supply fan, the

return fan, and the exhaust fan. These are used to tell the three motors whether they need to be

on or not. We also have the changeover which I had discussed before that determines the way

that the system works based on whether it is summer or winter. Last but not least are the

Proportional outputs. These are for the dampers and the valves. The dampers being controlled

are the outside air and exhaust air dampers. The valves being controlled are the hot water and

chilled water valves. On this board it is a 0-100% signal or a 0 to 10V AC signal.



Variable Air Volume Box (VAV Box)

The first thing that I would like to discuss would be the wiring diagram for the VAV box. This

diagram shows how the wiring is interfaced with the Smart II VAV control board. This wiring

diagram is shown in Figure 7 (below).

Figure 7: VAV Wiring Diagram



The VAV box wiring diagram is used to help show how we wired up all of the components to be

controlled by the board. The board has to be powered by a 24VAC power supply. In a building

with these systems, instead of putting the transformer in the box like we did, you would run that

24VAC signal throughout the building and to the power ports on the control board. There are

many things controlled by this board. We have the wired in Re-heat coil actuator in the

proportional output. This allows the board to give a signal anywhere from 0 to 10V to actuate

the actuator. The reheat coil takes the input of the air and heats it up by running hot water

through the coil. As before, the VAV boxes use a thermostat wired to the board. This time,

however, we use a thermostat to determine not only the temperature of the air with the hot water

coil, but to fluctuate the amount of air flow by use of a damper. The damper is also controlled by

the control board but this is a lower moving actuator. This actuator is actually open/close. The

actuator runs so slowly that it is able to back off the air and increase air flow without completely

opening up or shutting down. The board calculates the position of the damper by looking at the

temperature sensor and the pressure sensors which are also connected to the control board.

These two devices help in determining how much air flow in Cubic Feet per Minute (CFM) is

going through the VAV.

Next we have the loop diagram for the VAV box. This is what we designed to make

programming the VAV Smart II control board to make it work with the specifications of the

building. The loop chart that we designed for this VAV box is shown in figure 8 (below).



Figure 8: VAV Box Loop Chart

The VAV box loop chart explains our design and how we determined how to program on the

network and local level of this system. For Tech Expo we only showed the local Programming,

however, we used this same loop chart that we designed to make the network programming.

This board is laid out nearly the same as what the Control board for the panel was. Starting with

the left side at analog input 0 (AI-0) we have the room temperature. The room temperature

sensor is what tells the system whether it is to warm, to cold, or just right in the space. This tells

the system whether it needs to engage the cooling or heating coils or just keep the current

settings. The second analog input (AI-1) is the set-point adjust for the room thermostat. The

board itself is set to whatever temperature we want to keep the space temperature at. Usually,

this is 72-76 degrees. However, the thermostats offer a +4 -4 option so that way they can lower

the temperature or raise the temperature 4 degrees. The third analog input is actually a spare in

case we ever want to add on to the system. The next 2 inputs are not free like on the control

board. It shows the SMVP. This is the SMART II Velocity Probe. There is a temperature and

pressure reading with this device. This is what determines what the temperature and position of

the damper is before the heating coil. The next input (AI-5) is the Supply air temperature. This

is just after the reheat coil and tells you what the temperature of the air is going to the space.

Digital outputs 0 and 1 are used to open and close the damper on the VAV box based on the

temperature and pressure of the smvp probe. The proportional output of 0 to 10 volts is used to



fluctuate the position of the reheat coil valve. As you can see the entire function of these

components is based on the working of the control board.

Linked or Separate Project?

Many times looking at this project people have asked us whether these projects are linked or not.

The answer is yes and no. This project would be linked out in the field by the port on the bottom

right hand side of the control boards on both the panel and the VAV box. This is also the same

cable that sends all of this information back to the centralized network location. In the

simulation at tech expo we were not able to simulate the connection between the two systems

because we did not have the network to connect these two projects. Instead we hooked up a

supply fan to the supply fan terminal of the control panel and attached it to the input of the VAV

box. This helped us in simulating the VAV because it would back off on air flow so that way it

held its CFM set-point for air flow. So the answer is in the field we were linked by the network

but in general outside of the network these projects are not linked.



Budget:

The initial budget for this project included all of the necessary components to build a working system for

both the VAV box and Control Panel. In Table 1 (below), which was created in the beginning of the

project, all parts that we thought would be needed to create our project were included. The initial cost for this project was $3038.00. This was all funded by Wright Patterson Air Force base. We had no overhead

costs for the parts for this project.

Table 1: Initial Budget

Quantity Item Price Each

2 Terminal Strips $15.00

3 Transformers $34.00

2 Smart II Fan Coil Boards $375.00

1 Smart II VAV Board $470.00

10 Mounting relays $12.00

4 Wire Spools $39.00

1 Smart II PSU board $82.00

3 Smart II board Back Plates $30.00

4 Siemens Damper actuators $103.00

1 SVP Air Velocity Probe $65.00

1 Belimo Actuators $195.00

5 200A 250V fuses $8.00

2 Staefa Adjustable Thermostat $72.00

1 FK-T30 $42.00

1 Metal Control Panel Backing $150.00

2 4-20 mA power supplies $65.00

2 LED Temperature Displays $30.00



The final budget, Table 2 (below), shows the total cost of this project. This was after the

components that were insufficient. We did have some damaged components and had to replace

them. However, we were able to just replace the part with no problems. The full cost of this

project was covered by Wright Patterson Air Force Base. We needed to add the extra parts

because of the way that the equipment works. This allowed all of the equipment to work more

efficiently. The addition in fuses was for the current problem that we experienced early on in

this project. The total cost of the project was $4377.00.

Table 2: Final Budget

Quantity Item Price Each

2 Terminal Strips $15.00

4 Transformers $34.00

3 Smart II Fan Coil Boards $375.00

2 Smart II VAV Board $470.00

10 Mounting relays $12.00

4 Wire Spools $39.00

2 Smart II PSU board $82.00

3 Smart II board Back Plates $30.00

5 Siemens Damper actuators $103.00

1 SVP Air Velocity Probe $65.00

2 Belimo Actuators $195.00

15 200A 250V fuses $8.00

2 Staefa Adjustable Thermostat $72.00

1 FK-T30 $42.00

1 Metal Control Panel Backing $150.00

2 4-20 mA power supplies $65.00

2 LED Temperature Displays $30.00

We did not add in the labor cost because of my position at Wright Patterson. This project

actually gave Andrew Lemmon his full time job offer and paid for all of the parts so we did the

project free of charge.



Timeline:

We created a time line in the form of a Gantt chart in the first month of this project. This timeline broke

down the main aspects of the project, and assigned an amount of time to them. Figure 9 shows how much

time was initially assigned to each task.

Figure 9: Project Timeline

This Project we left plenty of room for error. We did this because we knew that in any project

there is going to be a little bit of error. There was a very large amount of work that had to be

done in a small amount of time. We worked to have this project done by the end of February.

We were able to keep our timeline accurate because of the time we allowed for errors in our

work. Because, this year we had less time to do this project before the technical exposition we

were able to get the project done however, we focused to be done by the end of February. This

was separated out so that we had time to do all of the wiring, programming and troubleshooting

for this project. We actually did make it out to take a video of the equipment working on time

and on schedule. This project turned out to be pretty much dead on when it came to getting all of

the tasks done by the correct date. All expectations were either met or exceeded for both Demo

Day and the Technical Exposition.



Problems Encountered:

Transformer problem

The label on the 120-24AC transformer was labeled incorrectly. We took this label for granted

and wired in the transformer how the label indicated we should. We then wired the control board

for the VAV into this transformer and turned the power on. Since the transformer was wired in

backwards, a cloud of smoke was consequently produced by a varistor on the control board,

signaling that there was a problem and we immediately shut off the power to the transformer.

After further examination, we noticed that this varistor was almost burnt completely through and

the entire control board would need to be replaced. Had we checked the voltage coming out of

the transformer before we wired the control board in, we would have noticed this error and

corrected it without any problem.

Board Port Problem

The wiring on the Air Handler Unit panel was completed to its entirety and we were then

simulating all of the actuators and sensors to ensure their proper simulation. Almost immediately

we noticed that one of the actuators was not simulating as it should. After approximately four

hours of intensive troubleshooting, we narrowed the problem down to the individual output port

of the control board being faulty. To solve this problem, we simply switched out the control

board for one with a working output port.

Simulation Problem

There were many problems when it came to actually simulating this project. The most glaring

one was the simulation of the indicator lights on the air handler unit panel. We designed the

panel to trip a relay and to turn on an indicator light whenever any of four switches were

switched inactive. This was to simulate any number of runtime errors that the system could

encounter when live. The problem was that none of our indicator lights worked and we could not

find where Wright Patterson Air Force Base had ordered theirs from. To solve this problem, we

simply switched out the indicator lights for small A/C fans to simulate that the fans would shut

off once the indicator lights were to turn on. This would simulate that the system would shut

down had any of those runtime errorsoccurred.

Grounding Problem

Once we had the air handler unit panel wired completely and we were testing the actuators on

the panel, we noticed that every time an actuator was activated, a fuse for the transformer that

ran the panel was blown. After extensive examination, we concluded that the actuator was

actually grounding out the power from the transformer, which consequently blew the fuse every

time it was activated. To fix this, we simply rewired the actuator so that the power was not

shorted to power.



Reheat coil actuator problem

The simulation for the Variable Air Volume box was fairly simple. It consisted of simulating the

actuators for it. We wired the Variable Air Volume box completely and were trying to simulate

the reheat coil actuator, but the actuator would not activate. We concluded that the actuator had

gone bad once the transformer blew the control panel from a previous problem, and switched out

the actuator for a working one.

Actuator Signal Problem

The final problem we encountered for the Air Handler Unit panel was the control board for the

actuator was actually outputting the wrong kind of signal. The control board was outputting an

A/C signal to the actuators, when the actuators need a D/C signal to activate. To fix this we

changed out the control board to one that output a D/C signal. This was the easiest way to fix this

problem instead of implementing a full-wave converter to convert the A/C signal to a D/C signal.

Future Recommendations:

Tech Expo Network

One of the things that we could not do on this project that we would have liked to have done was

to link these two projects through the network. Linking these project through the network would

have allowed everyone to see how the systems actually work together to increase and decrease

air flow as well as changing the temperature of the air going into the space.

BACnet Conversion

Another thing that we could do would be to convert to the newest system out there. We

could covert to the BACnet system. The only issue with this would be that this is a new system

and many of the technicians are not up to date with this new software.

Use new Siemens control system

The new Siemens controls system uses the BACnet. This uses coding to program which

is very similar to C++ in how it is written. These systems are also more expensive, almost twice

the cost. With these new systems though you only need one board for the control panel and have

many more options of things that you can do to manipulate the software and equipment. An

advantage to this would be you do not use the hand tool anymore. You would connect out in the

field with a laptop.



Conclusion:

The final outcome of this project was an overall success. We feel that we did not just merely

meet the requirements set for us by Wright Patterson Air Force Base, but we also exceeded them

by embellishing this project in order to make it more appealing to them. There are obviously

areas that we could have taken this project further, but Wright Patterson Air Force Base asked us

to keep it as simple as possible while still accomplishing their goals. In the end, they were

satisfied by our project and will be implementing it into one of their facilities in the near future.

References:

Staefa Integral Smart II Technical Manual



Appendix A

Network Programming

Smart II Control Fan Coil Board Network Programming Page 1



Smart II Control Fan Coil Board Network Programming Page 2

Smart II Control Fan Coil Board Sample Network Programming for

Auxiliary Board for Expansion



Appendix B

Photographs

Control Panel Photographs

Simulation Panel for the AHU control Panel

Top of control panel transformers and fuses



120VAC input power to panel

Temperature Control Valve for the Heating coil



Control Panel Damper actuator

Control Panel Power Supply Board



Control Panel Smart II Fan Coil Board

Wiring Behind the Smart II Fan Coil Board



VAV Box Photographs

Reheat Coil Actuator with Reheat Coil

Temperature Control Valve VAV Reheat Actuator



Thermostat for VAV Box

VAV Box Damper Actuator



VAV box Transformer from 120V to 24V

Smart II VAV Control Board



Wiring Behind Smart II VAV Control Board



Appendix C

Data Sheets for the actuators

Belimo



www.belimo.us/belimo/media//Technical_Documents/valve_actuators/LR_24_SR.pdf

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Siemens Actuators