Microtech 325 Instruction Manual

Group: UnitVentilator
PartNo.: 106102101
Date: July 1999
Installation & Maintenance Data IM 613-1
©1999 AAF-HermanNelson
Used with AAF-HermanNelson Models AVS, AVV, AVR, AHF,
AHV, AHR, AED, AEQ, AZS, AZQ, AZR, ARQ, ERQ
MicroTech®
Unit Ventilator Controller
HermanNelson
®

IM 613 / Page 2 (Rev. 7/99)
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
General Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Component Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Microprocessor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Setpoint Adjustment Potentiometers . . . . . . . . . . . . . . 5
Status LED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Power LED . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Hex Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Communication Ports . . . . . . . . . . . . . . . . . . . . . . . . . 6
Temperature Sensors . . . . . . . . . . . . . . . . . . . . . . . . . 6
Actuators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Standard Control Features . . . . . . . . . . . . . . . . . . . . . . . 6
Control Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Change and Step-&-Wait Algorithms . . . . . . . . . . . . . . 6
Compressor Short-Cycle Protection . . . . . . . . . . . . . . 7
Low Ambient Lockout . . . . . . . . . . . . . . . . . . . . . . . . . 7
Random Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Delayed Reversing Valve De-energization . . . . . . . . . 7
Emergency Heat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Defrost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Alarm Monitoring & Controlled Response . . . . . . . . . . 7
Factory Configured Options . . . . . . . . . . . . . . . . . . . . . 8
Communication Type . . . . . . . . . . . . . . . . . . . . . . . . . . 8
ASHRAE Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Room Temperature Sensor . . . . . . . . . . . . . . . . . . . . . 9
Remote Room Setpoint Adjustment . . . . . . . . . . . . . . 9
Tenant Override . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Day-Night Changeover . . . . . . . . . . . . . . . . . . . . . . . . 9
Ventilation Lockout . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Exhaust Fan Interlock . . . . . . . . . . . . . . . . . . . . . . . . . 9
Tables:
1. Status LED Indication . . . . . . . . . . . . . . . . . . . . . . . . 5
2. Hexadecimal to Decimal Conversion Guide . . . . . . . . 5
3. Alarm & Controlled Response Feature Availability . . 7
4. Programs and Software Models . . . . . . . . . . . . . . . . 10
5. Model-Specific Unit Ventilator Installation Literature 11
6. Program-Specific Sequence of Operation Literature 11
7. Network UVC Default Setpoints . . . . . . . . . . . . . . . . 12
8. Network Communications Port Terminal
Voltage Ranges . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
9. Alarm and Fault Code Summary . . . . . . . . . . . . . . . 18
10. RS-232 Communications Cable Terminations . . . . . 21
11. Inputs and Outputs for Program UV1*** Units . . . . . 22
12. Inputs and Outputs for Program UV2*** Units . . . . . 23
13. Inputs and Outputs for Program UV3*** Units . . . . . 23
14. Inputs and Outputs for Program UV4*** Units . . . . . 24
15. Inputs and Outputs for Program UV5*** Units . . . . . 24
16. Inputs and Outputs for Program UV6*** Units . . . . . 25
17. Inputs and Outputs for Program UV7*** Units . . . . . 25
18. Thermistor Chart . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Figures:
1. MicroTech Unit Ventilator Controller . . . . . . . . . . . . . . . 4
2. Hex Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Software ID Tag . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4. Digital Input Wiring Example . . . . . . . . . . . . . . . . . . . . 22
5. Relay Output Wiring Example . . . . . . . . . . . . . . . . . . . 22
6. Barber-Colman Actuator Position
Feedback Voltages . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
List of Illustrations
Table of Contents
Software ID . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Commissioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Pre-Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Required Tools and Literature . . . . . . . . . . . . . . . . . . 11
Unit Ventilator Identification . . . . . . . . . . . . . . . . . . . . 11
Field Wiring Check . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Setpoint Initialization . . . . . . . . . . . . . . . . . . . . . . . . . 12
Start-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Stand-alone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Master/Slave . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Diagnostics & Service . . . . . . . . . . . . . . . . . . . . . . . . . 18
Alarm Monitoring & Control . . . . . . . . . . . . . . . . . . . . 18
Fault Code Interpretation . . . . . . . . . . . . . . . . . . . . . . 18
Clearing Faults . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Alarm Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Service Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
PC Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
UVC Inputs and Outputs . . . . . . . . . . . . . . . . . . . . . . 21
Test Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
UVC Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Valve & Damper Actuator Calibration Procedures . . 29
Parts List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Certified Drawing
IM 613 / Page 3 (Rev. 7/99)
This manual provides information pertaining to the
MicroTech Unit Ventilator Controller (UVC) as applied in the
AAF-HermanNelsonUnit Ventilatorproductline.It should be used
in conjunction with the separate installation (Bulletin
No. OM101 through OM107) and sequence of operation
literature (see Tables 5 and 6).
CAUTION
This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with
the instructions, may cause harmful interference to radio communications. It has been tested and found to comply with the
limits for a Class B digital device, pursuant to Part 15 of the FCC rules. These limits are designed to provide reasonable
protectionagainstharmful interference when the equipment is operatedina residential environment. AAF-HermanNelson
disclaims any liability resulting from any interference or for the correction thereof.
CAUTION
This MicroTech controller contains static electricity sensitive components. A static discharge while handling electronic
circuitboards may cause damage to thecomponents.To prevent such damage during serviceinvolving board replacement,
discharge any static charge by touching grounded bare metal inside the unit before performing any service work.
WARNING
If the unit ventilator is to be used for temporary heating or cooling, the unit must first be properly commissioned. Failure to
comply with this requirement will void the warranty.
WARNING
This MicroTech control panel is designed to be stored and operated in temperatures from 32°F to 140°F and in relative
humidity up to 95% (noncondensing).
Introduction

IM 613 / Page 4 (Rev. 7/99)
Figure 1. MicroTech Unit Ventilator Controller
COMMB COMM A DIGITAL INPUT
GGGGGGS S S S S S GSGS
IN2
IN3IN4IN5IN6IN7IN12IN13
GS1SO
100
0
10
20
30 40
50
75
10
515
020 65 85
75
70 80
MINIMUM OA
POSITION UNOCCUPIED
OFFSET HEATING SETPOINT
(COOLING SETPOINT IS
FACTORY SET 6°F ABOVE
HEATING SETPOINT)
NETWORK
ADDRESS
HI LO
This device complies with part 15 of the FCC rules.
Operation is subject to the following 2 conditions:
(1) This device may not cause harmful interference.
(2) This device must accept any interference received, including
interference that may cause undesired operation.
SERIAL
EOS
PROG
LED
GO RELAY OUT
H12345678 AUX OUT
V910 PWR
G 24V
STATUS POWER
STATUS POWER
J1
J5
J4
J3
J2
J6 J7 J8 J9
%°F
MicroTech®
325 Controller
PART NO. 107627201
1 2 3 1 2 3 4 5 6 R 5 4
Remote Status
LED Output Relay Outputs Auxiliary
Outputs
(TRIAC)
Status LED Power Supply LED
Software ID tag
Electro-Mechanical
Relays
Hex Switches
Digital Inputs
Communication
Ports
Analog Inputs
Heating
Setpoint Pot
Minimum OA
Damper
Position Pot
Unoccupied
Offset Pot
65
70
8060
75
EOS + S/N tag
General Description
Component Data
TheMicroTech UnitVentilator Controller (UVC) is a microproces-
sor-based controller designed to provide sophisticated control of
an economizer-equipped AAF-HermanNelson unit ventilator. In
additionto providing normal operatingcontrol,theMicroTechUVC
provides alarm monitoring and alarm-specific component
shutdown if critical system conditions occur.
Each UVC is factory wired and factory programmed for the spe-
cific unit ventilator model and configuration options ordered by
the customer. The UVC can be wired and programmed to oper-
ate as a stand-alone controller, as a master or slave
controller, or as a MicroTech network controller.
Communication ports allow networking capability and
access to any UVC from an IBM compatible personal computer
(PC) equipped with Monitor software.
The MicroTech Unit Ventilator Controller (UVC) is shown in
Figure 1.

Certified Drawing
IM 613 / Page 5 (Rev. 7/99)
Status LED State Indication
On Continually Occupied Mode
On 1⁄2sec./ Off 51⁄2sec. Unoccupied Mode
On 51⁄2sec./ Off 1⁄2sec. Tenant Override Mode
Flashing* Alarm Condition
On 3 sec. / off 3 sec.** Calibration
on-board status LED. If used, the remote LED is connected to
the UVC at the terminal section labeled “LED.”
Power LED
The green, on-board power LED indicates microprocessor “on”
status. After applying power to the unit, the power LED should
illuminate continuously. For more information, refer to “Test
Procedures” in the “Service Information” section of this manual.
Hex Switches
TheUVC includes two hex (hexadecimal) switches that may need
to be set. The HI and LO hex switches are shown in Figures 1
and 2. Table 2 provides a hex-to-decimal conversion guide.
A“hex switch setting” is defined as the HI switch digit followed by
theLOswitchdigit. For example, a hex switch setting of 2Fwould
have the HI switch set to “2” and the LO switch set to “F.”
Stand-alone Units
On compressor-equipped units (self-contained or split system),
thehex switch setting defines the random start delay period.Each
unit on a common circuit or time clock should have a different
hex switch setting to ensure that multiple units do not start
simultaneously. The settings may be between 01 and 3F.
If the unit ventilator has no compressor, leave the hex switch
setting at 01.
Master, Slave and Network Units
The hex switch setting defines the controller’s network address.
(If the master, slave or network unit has a compressor, the
random start delay is also defined by the hex switch setting.) For
more information on master/slave addressing, refer to “Master/
Slave” in the “Start-up” section of this manual. For more
information on MicroTech network addressing, refer to the
MicroTech Network Master Panel installation bulletin.
Microprocessor
The UVC contains a microprocessor that is preprogrammed with
the software required to monitor and control the unit. It receives
inputdata from as many as 20 inputs (analog ordigital)andsends
commands to as many as 8 outputs (electromechanical relays).
(There are 2 additional solid-state relay “aux” outputs which are
notused for standardunitventilatorconfigurations.) Thequantities
and types of inputs and outputs are dependent on the unit venti-
lator model type and configuration options. All input and output
connections to the UVC are made using insulation
displacement type (IDC) terminal connectors.
The UVC uses field-adjustable setpoints and fixed,
preprogrammed parameters to maintain unit control. (Many of
the preprogrammed parameters can be adjusted with a PC
equipped with Monitor software.)
Setpoint Adjustment Potentiometers
There are three setpoint adjustment potentiometers (pots) on
the UVC:
• Minimum outdoor air damper position pot
• Heating setpoint pot
• Unoccupied offset adjustment pot
Note: On slave and network controllers, these three setpoint
valuesarereceivedvianetworkcommunications,andthe
pot settings are ignored. On slave controllers only, the
pot settings are used when communications are lost.
Therefore, it is recommended that appropriate “default”
pot settings be set for slave units.
Minimum Outdoor Air Damper Position Pot
The minimum position pot defines the minimum outdoor air (OA)
damper position. The OAdamper is typically held at its minimum
position when cooling is not required or when the OAtemperature
is not suitable for free cooling. Refer to the sequence of operation
document provided with your unit for more detailed
information.
Heating Setpoint Pot
The heating setpoint pot adjusts both the occupied cooling and
heating setpoints. The room occupied heating setpoint is shown
on the UVC faceplate. The room occupied cooling setpoint is
calculated by adding the deadband value to the heating setpoint
(deadband default = 6°F).
Unoccupied Offset Adjustment Pot
The unoccupied offset pot sets the offset value used to deter-
mine the unoccupied heating (or night setback) and unoccupied
cooling (or night setup) setpoints. The night setback setpoint is
calculated by subtracting the offset value from the occupied
heatingsetpoint.The night setup setpointis calculated by adding
the offset value to the occupied cooling setpoint.
Status LED
An amber, on-board status LED aids in diagnostics by indicating
the unit ventilator operating mode and alarm conditions. If there are
no current alarm conditions, the LED will indicate the unit operating
mode as shown in Table 1. If there are one or more alarm condi-
tions present, the LED will flash in a specific sequence to indi-
cateaparticularalarmcondition.Formoreinformation on alarms,
refer to the “Alarm Monitoring & Control” section of this manual.
A remote status LED is provided with all optional wall- mounted
temperature sensor packages. It has the same function as the
Figure 2. Hex Switches
Table 1.Status LED Indication
* Refer to Table 9 in the “Alarm Monitoring & Control” section of this manual.
** Calibration of OA Damper, F&BP Damper, and/or valve actuators will be
completed within approximately 5-min after power-on.
HIHex LO Hex Digit
Digit 0123456789ABCDEF
0 0*123456789101112131415
1 16171819202122232425262728293031
2 32333435363738394041424344454647
3 48495051525354555657585960616263
Table 2.Hexadecimal to Decimal Conversion Guide
* Hex switch setting 00 has a special purpose. It should not be used for
normal operation.

IM 613 / Page 6 (Rev. 7/99)
Actuators
The UVC uses hydraulic, spring return, floating control actuators
with position feedback for valve and damper modulation. These
actuatorsare controlled using the “Change” and “Step-and-Wait”
control algorithms.All cooling valves are normally closed, and all
heating valves (including “2-pipe” hot/chilled water) are normally
open. Outside air dampers are normally closed, and face and
bypass (F&BP) dampers are normally open to the coil face.
On some units equipped with F&BP dampers, a spring
return, two-position “end-of-cycle” (EOC) valve is used to pre-
vent overheating or overcooling when the damper is in the full
bypass position. Cooling EOC valves are normally closed, and
heatingEOCvalves(including “2-pipe” hot/chilled water) are nor-
mally open.
The following are standard MicroTech UVC control features as
applicable to the various unit ventilator model types:
• Control Temperature
• Change and Step-&-Wait control algorithms
• Compressor short-cycle protection
• Low ambient lockout
• Random start
• Delayed reversing valve de-energization
• Emergency heat
• Defrost
• Alarm monitoring & controlled response
Control Temperature
All unit ventilators are designed to control the room (or zone)
temperature. In order to maintain more stable room temperature
control, the UVC uses the concept of a “Control Temperature.”
Depending on the unit ventilator model, configuration, and
current mode of operation, the Control Temperature could be
either (1) the actual room temperature or (2) a weighted value
equal to 19/20 room temperature and 1/20 discharge air tem-
perature.
Throughout the remainder of this manual, “room temperature”
and “Control Temperature” will be assumed to be synonymous.
For further information, refer to the sequence of operation
document provided with your unit (see Table 6).
Change and Step-&-Wait Algorithms
The“Change” and “Step-and-Wait”algorithms work together in a
two-stage process to modulate actuators (valves or dampers) in
the unit ventilator. This control process enables the UVC to
maintain tight space temperature control with no overshoot.
There are several Change and Step-and-Wait parameters that
are factory set and adjustable only with a PC equipped with
Monitor software. For most applications, the factory-set
parameters will provide the best control. It is recommended that
these values not be changed.
Following is a brief description of the Change and Step-and-Wait
functions. For additional information, refer to the
MicroTech Unit
Ventilator Controller Monitor Program User’s Manual
.
Change
The Change function changes the valve or damper position
setpoint in response to the deviation of the room temperature
fromitssetpoint(offset).The amount of actuator-position setpoint
change varies and is dependent on the amount of room
temperature setpoint offset.
The Change algorithm is executed on a factory-set, periodic ba-
sis.
Step-and-Wait
The Step-and-Wait function causes the valve or damper to open
orclose as required to maintain theChangefunction’scalculated
position setpoint. The “step” period is the amount of time the
electric actuator is driven either open or closed, and the “wait”
period is the amount of time the actuator holds its position. The
“step” and “wait” periods vary and are dependent on the amount
of actuator-position setpoint offset.
The Step-and-Wait algorithm is executed on a periodic
basis. This period is a factory-set constant that is equal to the
sum of the “step” and “wait” periods described above.
Communication Ports
The UVC has two communication ports: CommA and Comm B.
Following are brief descriptions of each communication port’s
function. For further information, refer to the “Service
Information” section of this manual.
Stand-alone and Network Units
Comm B is for MicroTech network communications to the Local
MasterController using an RS-485 format. (CommBisconfigured
this way in a stand-alone unit, but not used.) Comm A is for
communicationstoan IBM compatible PC using an RS-232format.
Master/Slave Units
Communicationsbetweenmaster and slave UVC’sisdoneusing
an RS-485 format. On the master unit, Comm B is used for
communications to the slaves, and Comm A is not used. On a
slave unit, Comm B is used for communications to the master,
and Comm A is available for communications to an IBM
compatible PC using an RS-232 format.
Temperature Sensors
TheMicroTech UVC uses negative temperature coefficient(NTC)
thermistors for temperature sensing. A thermistor chart, which
provides voltage-to-temperature and resistance-to-temperature
conversion data, is included in the “Service Information” section
of this manual (Table 18).
Standard Control Features

Certified Drawing
IM 613 / Page 7 (Rev. 7/99)
Compressor Short-Cycle Protection
All compressor-equipped unit ventilator models (self-contained
or split system) include compressor short-cycle protection.
When a compressor is energized, it will remain energized for at
least 2 minutes before the temperature control sequence will be
allowed to de-energize it. An alarm condition can override this
“minimum-on” timer and stop the compressor if necessary.
When a compressor is de-energized, it will remain
de-energized for at least 3 minutes before the temperature
control sequence will be allowed to energize it again.
Low Ambient Lockout
Except for the water source heat pump (WSHP) models, all
compressor-equipped unit ventilators (self-contained or split
system) include compressor low ambient lockout protection.
Thisfeaturewill prevent compressor operation when the unitis in
the cooling mode and the outdoor air temperature is below 59°F.
Random Start
Arandom start feature is provided with all compressor-equipped
unit ventilators (self-contained or split system). This feature will
prevent simultaneous compressor start-up that could otherwise
occur after the following events:
• Unit power-up
• Unoccupied to occupied changeover
• Brownout condition
The compressor start delay can be from 1 to 63 seconds and is
determinedby the UVC hex switch setting.Formore information,
refer to “Hex Switches” in the “Component Data” section of this
manual.
Delayed Reversing Valve De-energization
All heat pump unit ventilator models have a 60-second (default)
reversing valve de-energization delay feature.
This delay prevents the reversing valve from returning to its
normal (cooling) position for a period of 60 seconds after the
compressorisde-energizedwhentheunit is in the heating mode.
Ifnecessary, an alarm condition can override the 60-second timer
and de-energize the reversing valve with the compressor.
Emergency Heat
All heat pump unit ventilator models that are equipped with
electric heat have an emergency heat feature.
The emergency heat mode is initiated by depressing the
momentary, unit-mountedemergency heat switch. When the unit
is in the emergency heat mode, the following actions occur:
• Compressor is immediately de-energized and locked out.
• Reversing valve is de-energized after a delay.
• Electric heat is staged to maintain the room heating
setpoint regardless of outdoor air temperature
(ASHP units) or entering water temperature (WSHP units).
The unit ventilator may be returned to normal operation by
cycling power to the controller (use fan switch or main
power switch).
ASHP Units Only: Note that the emergency heat switch (SW5)
and defrost control contacts are wired in parallel and use the
same UVC digital input (DI-3). The emergency heat switch
provides a momentary contact closure and the defrost control
provides a maintained contact closure. Therefore, do not hold
the emergency heat switch down or the unit may enter the
defrost mode instead of the desired emergency heat mode.
Defrost
TheAEairsource heat pump (ASHP) unit ventilator models have
a defrost cycle which prevents frost from building up on the
outdoor coil when the unit is operating in the heating mode.
An external defrost control provides a maintained contact
closure to the UVC when defrost is required.
When the unit is in the defrost mode, the following
actions occur:
• Reversingvalve isde-energized(unit enters “cooling”cycle).
• Electric heat is staged to maintain the room setpoint
regardless of outdoor air temperature.
• Compressor cannot be de-energized by room temperature
control until defrost mode ends.
For further information on the defrost control cycle, refer to
Bulletin No. OM 101, MicroTech Unit Ventilator Controller
Sequences of Operation: Program UV1.
Alarm Monitoring & Controlled Response
The MicroTech UVC is capable of sophisticated alarm
monitoring and controlled response functions. Each alarm
(or “fault”) is prioritized, indicated, and responded to with the
appropriate action. If multiple alarms are present, the alarm with
the highest priority is indicated.
A summary of the available alarm features is shown in Table 3.
For more information, refer to the “Alarm Monitoring &
Control” section of this manual. Following are brief descriptions
of each feature.
Alarm & Controlled Response Feature Unit Ventilator Model
AE AZ AR AV AH
Sensor Diagnostics (Each Sensor) • • • • •
Actuator Feedback Diagnostics •••••
(Each Actuator)
Brownout Protection • • • • •
High Pressure • • •
Low Coil Temperature (DX and/or Water) • • • • •
Low Refrigerant Temperature (Water Coil) •
Communication Error (Master/Slave Only) • • • • •
Change Filter (Network Units Only) • • • • •
Table3.Alarm & Controlled Response FeatureAvailability

IM 613 / Page 8 (Rev. 7/99)
Sensor Diagnostics
If a temperature sensor’s value is out of range, the UVC will
detect it and take the appropriate action. Each sensor fault has a
specific priority, alarm indication, and set of response actions.
Actuator Feedback Diagnostics
The UVC will monitor the position feedback voltages of every
modulating actuator provided with a particular unit ventilator. If a
feedback value is out of range, the UVC will detect it and
discontinue control of that actuator. Each feedback failure fault
has a specific priority and alarm indication.
Brownout Protection
The brownout feature is meant to protect the compressor and
electric heat contactors from low voltage or “brownout” condi-
tions. If the supply voltage to the unit ventilator is below 85% of
the nameplate value, the UVC will detect it, indicate it, and
de-energize the compressor and electric heaters.
High Pressure
Ifexcessive pressure in the refrigeration circuitisdetected by the
external pressure switch, the compressor will be de-energized
immediately (hardware wired). The UVC will immediately
de-energize the reversing valve, disable the compressor and
indicate the alarm.
Low CoilTemperature
External thermostats will sense the DX and water coil
temperatures(if present). The UVC willmonitor each thermostat,
and if a low coil temperature is detected, alarm indication and
the appropriate action will occur.
Low RefrigerantTemperature (Water Coil)
If the WSHP unit is in the heating mode and the refrigerant
temperature is too low, the UVC will indicate the alarm and
immediately de-energize the compressor and reversing valve.
Communication Error (Master/Slave Units Only)
If a communication error occurs between a slave UVC and its
master, the alarm will be indicated at the slave, and the affected
units will continue operating. For further information, refer to the
description of the master/slave communication type in the
“Factory Configured Options” section of this manual.
Change Filter (Network Units Only)
When the unit ventilator fan run-time exceeds a network-
adjustable setpoint, a change filter alarm is indicated locally and
over the MicroTech network.
The master controller establishes the following parameters for
itself and for each of its slaves:
• Operatingmode(occupied,unoccupied,ortenantoverride)
• Minimum OA damper position setpoint
• Occupied heating and cooling setpoints
• Unoccupied heating and cooling setpoints
Because each UVC in the zone uses its own room
temperature sensor and a common room temperature setpoint,
even temperature control will be maintained regardless of any
load variation within the zone.
Master: A master UVC is similar to stand-alone UVC. The only
difference is that Comm B of a master controller is used for
master/slave network communications. The minimum position
setpoint, room setpoint, unoccupied offset, operating mode, and
remote setpoint adjustment (if used) must be set at the master.
Slave: A slave UVC receives its operating mode and the above
setpoint information from its master. When communications are
established between a slave and its master, the slave will ignore
its three on-board setpoint potentiometers.
Communication Failure: If the communication link between a
slave and its master fails, the slave UVC will indicate the alarm
and continue to operate using the temperature and minimum
position setpoints defined by its on-board potentiometers. Its
operating mode will be that last received from its master, or if
power is cycled, it will default to occupied.
MicroTech Network
A variety of MicroTech unit and auxiliary controllers can be
interconnected to form a MicroTech network. A MicroTech
network provides a building operator with the capability to perform
advanced equipment control and monitoring from a central or
remote location. A network UVC is a controller that has been
programmed with the software required to operate in a Micro-
Tech network. The following features are provided for each
network UVC over the MicroTech network:
In addition to the various heating and cooling options, the
AAF-HermanNelson product line provides several factory-
configured options that affect installation requirements and unit
control. These options are either factory programmed, factory
wired, or both. The model number code string specifies which
options are present in a particular unit ventilator. The following
options are described in this section:
• Communicationtype (stand-alone, master/slave ornetwork)
• ASHRAE cycle II
• Room temperature sensor (unit or wall mounted)
• Tenant override (unit or wall mounted)
• Remote room setpoint adjustment
• Day-nightchangeover
• Ventilation lockout
• Exhaust fan interlock
Communication Type
All Unit Ventilator Controllers can be programmed to operate in
one of the following communication modes:
• Stand-alone
• Master/slave
• MicroTech network
Stand-alone
A stand-alone UVC does not communicate over a network. It is
independent and capable of performing complete room
temperature and ventilation control.
Master/Slave
The master/slave application is designed to provide even
temperature control of a zone containing up to six unit
ventilators. One controller in the zone must be designated and
programmed to be the master, and up to five controllers may be
designated and programmed to be its slaves.
Factory Configured Options

Certified Drawing
IM 613 / Page 9 (Rev. 7/99)
• Day-night changeover scheduling
• Heating and cooling setpoint adjustment
• Minimum OA damper position setpoint adjustment
• Ventilation lockout
• Change filter alarm
• Demand limiting
Communication Failure: If the MicroTech network communica-
tion link failures for any reason, the affected UVC will remain
operational. Its operating mode will be that last received over the
network, or if power is cycled, it will default to occupied. Its mini-
mum position, heating, and cooling setpoints will be those last
receivedoverthe network, regardless of whether power is cycled.
ASHRAE Cycle
All unit ventilator controllers are factory programmed to follow
ASHRAE II unit ventilator control cycle. The UVC uses the room
temperature sensor to control the heating, ventilating, and
cooling functions of the unit ventilator.
ASHRAE II Cycle
A discharge air temperature sensor is installed in all unit
ventilators. If necessary, the ASHRAE II control algorithm can
override room control and modify the heating, ventilating, and
cooling functions (as available) to prevent the discharge air
temperaturefromfallingbelowthedischargeairlow limit setpoint.
The discharge air low limit setpoints and sequences of operation
vary and are dependent on the unit ventilator model and
configuration. For further information, refer to the sequence of
operation document (Bulletin No. OM101 through OM107)
provided with your unit.
Room Temperature Sensor
A room temperature sensor is required for all unit ventilators. It
may be unit mounted or wall mounted.
Unit Mounted Sensor
The unit mounted room sensor is factory installed and factory
wired. It is located within an aspirating sampling chamber behind
the unit ventilator fan access panel.
Wall Mounted Sensor
There are optional wall sensor packages available. All wall
sensors include a remote status LED. Tenant override, setpoint
adjustment, and bimetal thermometer are optional wall sensor
features that are available in any combination.
The wall mounted sensor must be field installed and field wired
to the unit ventilator. Refer to the model-specific unit
ventilator installation manual and to Bulletin No. IM 529, Micro-
Tech Room Temperature Sensors, for information on wall sensor
package installation.
Remote Room Setpoint Adjustment
The remote setpoint adjustment potentiometer allows the room
setpoint to be adjusted up or down by as much as 3°F. It is
available with several of the optional wall sensor packages, and
it may be used with all except slave-type Unit Ventilator Control-
lers.
Tenant Override
A unit mounted or wall mounted tenant override switch is
available for use with all except slave-type Unit Ventilator
Controllers. The tenant override switch provides a momentary
contact closure that causes the unit to enter the “tenant override”
operating mode for a set time period (default = 120 minutes).
Except for the fact that it is temporary, the tenant override
operating mode is identical to the occupied operating mode.
Unit MountedTenant Override Switch
The optional unit mounted tenant override switch is factory
installed and factory wired.
Wall MountedTenant Override Switch
Thewall mounted tenant override switch isavailablewith several
of the optional wall sensor packages. The wall sensor package
must be field installed and field wired to the unit ventilator. Refer
to the model-specific unit ventilator installation manual and to
Bulletin No. IM 529, MicroTech Room Temperature Sensors, for
information on wall sensor package installation.
Day-Night Changover
Day-night changeover control is required to change the unit
ventilatoroperatingmode from occupied (default) to unoccupied.
When the unit is in the unoccupied operating mode, the OA
damperisclosed, and the night setback and setup room setpoints
are maintained. The fan is energized only when heating or
cooling is required. For further information, refer to sequence of
operation document provided with your unit.
Stand-alone and Master Units
The day-night changeover function is provided by a factory-
installed or field-installed device. The following changeover
options are available:
• Relay (24 VAC coil for field connection)
• Time clock and holiday switch
• Manual day-night switch
• Pneumatic-electric (PE) switch or relay (field supplied &
installed)
All of the above methods must provide a maintained
contact closure (at DI-2) to place the UVC into the unoccupied
operating mode. When the contacts are open (or if none are
provided), the unit will be in the occupied operating mode.
Network Units
The day-night changeover function is provided over the Micro-
Tech network. It can be scheduled for every controller on the
network using the UVC Monitor program.
Ventilation Lockout
The ventilation lockout option provides a means of overriding
normalUVCcontrolandclosingtheoutdoorair damper at any time.
Stand-alone, Master, and Slave Units
When the ventilation lockout option is ordered, a relay (24 or 115
VAC) is factory installed and wired to the UVC. The OA damper
will close when the field-connected relay coil is energized.
Network Units
The ventilation lockout function is provided over the MicroTech
network.
Exhaust Fan Interlock
The exhaust fan interlock option provides a means of overriding
normal UVC control and fully opening the outdoor air damper at
any time. Typically, this application is used to supply makeup air
when an exhaust fan is energized.
When the exhaust fan interlock option is ordered, a relay (24
VAC) is factory installed and wired to the UVC. The OA damper
will open when the field-connected relay coil is energized.

IM 613 / Page 10 (Rev. 7/99)
UV 1 S 2 B
Unit Ventilator
Program Number
Unit Type
S = Stand-alone, Open Protocol
M = Master/Slave
N = MicroTech Network
Software Version (Numeric)
Software Version Revision (Alphabetical)
Unit Ventilator Controller software is factory installed and tested
in each unit prior to shipment. The software is identified by a
program code and “software model” number printed on a small
label attached to the controller. Refer to Figure 3.
Table 4 shows the 7 programs and 18 software models used for
the various unit ventilator models and configurations. As shown
in the table, a program comprises one or more software models.
Program number codification is as follows:
Abbreviations:
ASHP Air source heat pump
WSHP Water source heat pump
2-Pipe Common hot water and chilled water coil
4-Pipe Separate wet heat and chilled water coils
DX Direct expansion (refrigerant)
CW Chilled water
Wet Heat Steam or hot water heat
Table 4.Programs and Software Models
Software ModelProgram Number
Program Software Unit Ventilator Model Configuration
Model AE AZ AR AV AH Description
UV1*** MDL00 • ASHP with Electric Heat
UV2*** MDL02 • WSHP with Electric Heat
MDL03 • WSHP Only
MDL04 • • • DX Cooling with Electric Heat
UV3*** MDL05 • • DX Cooling Only
MDL06 • • Electric Heat Only
UV4*** MDL07 • • • DX with Wet Heat, Valve Control
MDL08 • • • DX with Wet Heat, Damper Control
MDL09 • • Wet Heat Only, Valve Control
UV5*** MDL10 • • Wet Heat Only, Damper Control
MDL11 • • 2-Pipe, Valve Control
MDL12 • • 2-Pipe, Damper Control
UV6*** MDL13 • • 4-Pipe, Valve Control
MDL14 • • 4-Pipe, Damper Control
MDL15 • • CW Cooling Only, Valve Control
UV7*** MDL16 • • CW Cooling Only, Damper Control
MDL17 • • CW with Electric Heat, Valve Control
MDL18 • • CW with Electric Heat, Damper Control
Software ID
Figure 3. Software ID Tag

Certified Drawing
IM 613 / Page 11 (Rev. 7/99)
The following commissioning procedures pertain to unit ventila-
torsequippedwiththeMicroTech Unit Ventilator Controller (UVC).
Theseprocedures must be performed in addition to the mechanical
and electrical system commissioning procedures that are
outlined in the model-specific installation literature. Table 5
provides a listing of this literature.
Caution: Before power is applied to any unit, the pre-start
procedures in the model-specific installation literature must be
closelyfollowed.
WARNING
ELECTRICAL SHOCK HAZARD! Could cause severe injury or death. Failure to bond the frame of this equipment to the
building electrical ground by use of the grounding terminal provided or other acceptable means may result in electrical shock.
Service must be performed only by qualified personnel.
Alarge part of the commissioning procedure is ensuring that the
unit ventilator operates according to its programmed sequence
of operation. The unit ventilator sequences of operation are
described in the program-specific literature listed in Table 6.
Commissioning
Unit Ventilator Installation & Maintenance
Model Data Bulletin Number
AE UV-3-204 (IM 502)
AZ UV-3-205 (IM 503)
AR UV-3-202 (IM 504)
AV/AH UV-3-200 (IM 506)
Table 5.Model-Specific Unit Ventilator Installation Literature
UVC Program Operation Manual Bulletin Number
UV1*** OM 101
UV2*** OM 102
UV3*** OM 103
UV4*** OM 104
UV5*** OM 105
UV6*** OM 106
UV7*** OM 107
Table6.Program-SpecificSequenceof OperationLiterature
Pre-Start
Required Tools and Literature
The following tools and additional literature may be required to
properly commission a MicroTech UVC.
Tools:
1. Digital voltmeter
2. Digital ohmmeter
3. Digital thermometer
4. General technician’s tools
5. PC equipped with Monitor software (required for master/
slave and Network UVC, optional for stand-alone UVC’s)
Literature:
1. Model-specificunit ventilator installation bulletin (see Table
5)
2. Program-specific sequence of operation bulletin
(see Table 6)
Unit Ventilator Identification
TheAAF-McQuayunit ventilators look similar; however,there are
significant internal differences which are defined by the model
number code string. In addition to the basic heating and cooling
equipment, the model number code string specifies which
factory-configured options have been provided. These options
determine the internal wiring configuration and the field
wiring requirements.
Obviously, it is extremely important that the correct unit
ventilator be placed in the correct location in accordance with job
requirements. Proper unit ventilator location should have been
determined during the installation process. Nevertheless, proper
location must be verified during the commissioning process.
KnowYour UnitVentilator
Before commissioning can proceed, the start-up technician must
know which options are supposed to be present on a particular
unit ventilator.
1. Check the model number code string against the job
requirements. Refer to the unit-specific installation bulletin
for a guide to model number nomenclature.
2. Check the program and software model numbers against
theunitmodelnumber code string. The UVC software must
be compatible with the unit ventilator configuration. Refer
to the “Software ID” section of this manual.
Note: If a PC is being used for commissioning, check the
software ID using the Monitor program. The controller’s
program is identified on one of the display screens.
Field Wiring Check
The unit ventilator factory-configured options determine the low
voltage field wiring requirements. If a specific option is present
on a particular unit ventilator (as denoted by the model number),
the associated field wiring (if any) must be checked.
Detailed electrical installation instructions and field wiring
diagrams are included in the model-specific installation literature
supplied with each unit ventilator. Referring to this literature and
using the following check lists, the start-up technician should
thoroughly check the electrical installation before the
commissioning process proceeds.
Wall Sensor Packages
1. Check that the cable is twisted and shielded.
2. Check that the required number of conductorsare available.
3. Check that the shield is grounded in accordance with the
installation literature.

IM 613 / Page 12 (Rev. 7/99)
4. Checkthatthe conductors have been terminated at theunit
and the wall sensor package in accordance with the field
wiring diagram.
5. Check that the cablelengthbetweenthewall sensor package
and its UVC does not exceed 250 feet.
6. 460V,Type AE & AZ Only: Check that 600-volt rated cable
has been used.
Network Communication (Master/Slave or MicroTech
Network Units)
1. Check that the cable is a twisted, shielded pair of
conductors.
2. Check that the shield is grounded in accordance with the
installation literature.
3. Checkthattheconductors have beenterminatedatthe units
in accordance with the field wiring diagram.
4. At the UVC board, verify that the IDC connectors are
disconnected from the Comm A and Comm B ports.
(They will be connected during the start-up process.)
5. 460V,Type AE & AZ Only:Check that 600-volt rated cable
has been used.
6. MicroTech Network Units Only: Check that the conduc-
tors have been terminated at the Local Master Controller
(LMC) in accordance with the field wiring diagram supplied
withthe LMC. Check that the cable length between theLMC
and the farthest UVC does not exceed 5000 feet.
Day-Night Changeover (Stand-alone or Master Units)
1. Checkthatthe conductors have been terminated at theunit
in accordance with the field wiring diagram.
Note: Fieldterminations are not requiredforthefactory-mounted
time clock and manual switch options.
2. Check that the ultimate changeover device provides the
proper action at the UVC. The dry contacts connected to
DI-2 must be “open for occupied” and “closed for
unoccupied.” If used, the factory-installed relay is wired so
that it must be “de-energized for occupied” and “energized
forunoccupied.”
3. 460V, Type AE & AZ Only: Check that 600-volt rated
conductors have been used.
Ventilation Lockout (Stand-alone, Master or Slave Units)
1. Checkthatthe conductors have been terminated at theunit
in accordance with the field wiring diagram.
2. Check that the field-supplied device energizes the factory-
installed relay when ventilation lockout is desired.
3. 460V, Type AE & AZ Only: Check that 600-volt rated
conductors have been used.
Exhaust Fan Interlock
1. Checkthatthe conductors have been terminated at theunit
in accordance with the field wiring diagram.
2. Check that the field-supplied device energizes the factory-
installed relay when exhaust fan interlock is desired.
3. 460V, Type AE & AZ Only: Check that 600-volt rated
conductors have been used.
Setpoint Value
Occupied Cooling 78°F
Occupied Heating 72°F
Unoccupied Cooling 88°F
Unoccupied Heating 62°F
Minimum OA Damper Position 20%
Table 7. Network UVC Default Setpoints
Remote Condensing or Heat Pump Unit (AV/AH Units Only)
Check that the conductors have been terminated at the unit in
accordance with the field wiring diagram.
Setpoint Initialization
Stand-alone and Master/Slave Units
Theheating setpoint,unoccupiedoffset,and minimumOAdamper
position potentiometers (pots) should be set to the desired
settings prior to start-up. For more information, refer to “Setpoint
Adjustment Potentiometers” in the “Component Data” section of
this manual.
Note: In a master/slave application, the master’s pot
settings define the setpoint values for its slave controllers.
If communications fail, the affected slaves read their
setpoint values from their own setpoint pots. For this
reason,it is recommendedthatthethree on-board setpoint
potson each slave be set so that they match the master’s
settings.
Network Units
The three setpoint adjustment potentiometers on a network unit
arenotoperational.TheUVC setpointvalues are held in memory
and can only be modified over the MicroTech network. Initially,
beforeanychanges are made over the network, theUVCwill use
the default, factory-set setpoints shown in Table 7.
CAUTION
On AH units, it is recommended that the outdoor air
temperaturesensor be located so that it will accurately sense
the outdoor air temperature. If this is not done, improper unit
operationordamagetotheremotecondensingor heat pump
unit could occur. The best location for the sensor is either
outside the building (shielded from solar radiation) or in the
outdoor air ductwork very near the intake.

Certified Drawing
IM 613 / Page 13 (Rev. 7/99)
Following are UVC start-up procedures for each communication
type. The start-up procedure must be performed by a qualified
technician for every UVC on a job.
Stand-alone
Because stand-alone controllers are independent of each other,
they may be started in any order.
PC Access
APC is not required for stand-alone UVC start-up; however, the
start-up process will be easier and faster if a PC is used. If a PC
is used, it must be equipped with Monitor software. For further
information,referto “PC Connection” in the “Service Information”
section of this manual.
Procedure for Each Stand-alone UVC
1. Verify that the main power switch is at “Off.”
2. Verify that the hex switch setting is not “00” or “FF.”
These settings are reserved for special applications. For
further information, refer to “Hex Switches” in the
“Component Data” section of this manual.
3. Compressorized Units Only (Self-contained or Split
System): Set hex switches for random start delay.
Valid settings are between 01 and 3F. For further
information, refer to “Random Start” in the “Standard
Control Features” section of this manual.
4. Apply power to the unit.
Turn the main power switch to “On” and the motor speed
switchto the desired speed, wait 5-minutesuntilcalibration
is complete.
5. Check the status LED and operating mode changeover
devices. The status LED should illuminate after calibration.
If a wall sensor package is used, the remote status LED
should also illuminate. Referring to Table 1, verify that the
day-night changeover and tenant override options (if
present) are working properly. Do this by switching these
devices and observing the status LED.
6. Verify that the unit ventilatorisoperatinginaccordancewith
its sequence of operation as outlined in the appropriate
documentation (refer to Table 6).
Since the sensed temperatures are fixed at any given
moment, adjust the room setpoint and unoccupied offset
pots to obtain the expected heating or cooling control
actions. If a PC is available, adjust any other applicable
parameters to obtain the expected UVC control actions.
7. Check the remote setpoint adjustment pot operation
(if present).
Verify that the expected UVC control action occurs when
the remote pot is adjusted up or down.
8. Check that the ventilation lockout option works properly
(if present).
Communication Acceptable
Port Terminal Voltage Reading
4 (+) 3.0 ±0.3 VDC
5 (-) 2.0 ±0.3 VDC
6 (ground) 0.0 ±0.2 VDC
Table8.NetworkCommunicationPortTerminalVoltageRanges
Start-Up
When the unit is in the occupied operating mode, verify
that the OA damper closes when the ventilation lockout
relay is energized.
9. Check that the exhaust fan interlock option works properly
(if present).
Verify that the OA damper opens when the exhaust fan
interlock relay is energized.
Master/Slave
Because it provides operating mode and setpoint information to
the slaves on its network, the master UVC must be started
before any slave. After the master has been started, the slaves
maybestartedin any order.However,ifthestart-uporder follows
the daisy chain from the master UVC to successive slaves, it will
be easier to detect any wiring problems that may exist in the
communications trunk.
Toperformthesetup procedures on the next page you must have
the Windows Monitor program installed on a PC, the PC must be
connected with proper cabling to Port-A on the MicroTech con-
troller, and you must have established communication between
the PC and the controller. The cable kit required to properly
connect a 9-pin serial PC port to Port-Aon a MicroTech controller
is P/N 057186802 which will contain cables P/N 067784501 and
P/N 067784503.
The DOS Monitor program may also be used to perform these
setup procedures.
Points to keep in mind about Master/Slave Units
• Master/Slave controllers must be either all MicroTech 125
or all MicroTech 325; you cannot mix 125’s with 325’s and
vice versa.
• Master/Slave networks that have both new and old EOS
version MicroTech 325 controllers must use a new EOS
controller for the Master (new EOS 325 controllers are
labeled 21.169 or 21.A9, all other 325’s are old EOS).
• Master/Slave controllers both use the same program
(UV*M**.COD).
• All units are shipped as stand-alone units. Master/Slave
code must be downloaded and then Master/Slave configu-
ration performed.
• Slave UVC’s are considered to be independent slaves, this
meansthat Slave UVC’sobtain their setpoints fromtheMas-
terUVCbuttheSlaveUVC’sthen operate basedupontheir
own sensors.
• Port-A on a Master UVC unit will not communicate as you
mayexpect a stand-alone UVC to communicate.Ifyoumust
connect directly with a Master UVC, you must first set its
HEXnetworkaddressswitchestoFFthencyclepower.The
addresstouseintheMonitorprogramwouldthenbe00.FF.
While the HEX network address switches are set at FF, the
Master UVC will not communicate with the Slave UVC’s
properly; therefore, you must remember to return the HEX
switches to their proper settings, then cycle power when
you are done.

IM 613 / Page 14 (Rev. 7/99)
• Slave units will communicate as expected when your PC is
connected to Port-A, simply make sure you use the correct
address for each Slave when using the Monitor program.
For example, if the Slave HEX switches are set at 01, then
theaddress youwilluse in theMonitorprogram willbe01.01;
if the HEX switches are set to 02 on the Slave UVC, then
you use 01.02 as the address, etc.
• Ifyou need to communicate with aUVCthat is already con-
figuredasa Master and is part of an operating Master/Slave
network, then use the following method. For example, to
calibrate actuators on a Master UVC, connect to Port-Aon
a Slave unit and set the Controller Address box on the
Monitor Read/Write screen to 01.00. This will gain access
to the Master controller so that actuator calibration may be
performed.
• Whena slaveUVCloses communication totheMaster UVC,
the Slave UVC will operate based upon its potentiometer
settings (i.e. % Minimum OAPosition, etc.) located on the
faceplate of the Slave UVC.
Initial Master Configuration
1. Connect the Master UVC’s Port-A to your PC using the
proper cables.
2. Adjust the Master UVC’s Hex switches to FF and cycle unit
power (auto calibration will occur).
3. Using the Windows Monitor software establish communi-
cations with the controller using address 00.FF.
4. IntheWindowsMonitor program, securethecorrectMaster/
Slave software, then go to the Support menu and choose
Read/Write.
5. On the Read/Write screen, in the Operation box select the
Monitor radio button by clicking on it. In the Display box
select the Decimal radio button by clicking on it.
6. Enter the following string of memory addresses into the
Memory Address box exactly as shown then press the
Enter key: 8011-8012,8001-8002,0911,0204.
7. Write a value of 73 to location 8011 by clicking on the
current value.
8. Write a value equal to the number of slaves you will have
into location 8012 by clicking on the current value of 8012.
This value must be 1 through 5 as the minimum number of
slaves is 1 and the maximum is 5.
9. Write a value of 0 to location 0911 by clicking on the cur-
rent value.
10. Write a value of 4 to location 0204 to reset the controller.
11. Change location 8001 to equal location 8002 if there is a
difference. If no difference, go to the next step.
12. Change the Master UVC Hex switches to 01.
13. Write a value of 4 to location 0204 to again reset the
controller.
14. Master configuration is complete.
15. At this point you will lose communications with the Master
UVC through Port-Aon the Master. If you need to commu-
nicate with the Master UVC, the recommended method is
to connect to one of the Slave UVC’s Port-A and set the
network address within the Monitor program to 01.00.
Initial Slave Configuration
1. Connect all Slave UVC Port-B’s to the Master UVC’s Port-
B as shown on the drawings provided with the unit
ventilator (these drawings are typically mounted on the
inside of one of the unit ventilators removable panels).
2. ConnecttheSlave UVC’sPort-Atothe PC using the proper
cables.
3. Using the Windows Monitor software, establish communi-
cations with the controller using network addresses 00.FF.
4. In the Windows Monitor program, secure the correct
Master/Slave sotware, then go to the Support menu and
choose Read/Write.
5. On the Read/Write screen, in the Operation box select the
Monitor radio button by clicking on it. In the Display box,
select the Decimal radio button by clicking on it.
6. Enter the following string of memory addresses into the
Memory Address box exactly as shown, then press the
Enter Key: 8011-8012,8001-8002,0911,0204.
7. Write a value of 33 to location 8011 by clicking on the
current value.
8. Write a value of 0 to location 8012 by clicking on the
current value.
9. Write a value of 1 to location 0911 by clicking on the
current value.
10. Write a value of 4 to location 0204 to reset the controller.
11. Changelocation 8001 to equal 8002 if there is a difference.
If no difference, go to the next step.
12. Change the Slave UVC Hex switches to 01 for Slave-1, 02-
for Slave-2, 03 for Slave-3, etc.
13. Write a value of 4 to location 0204 to again reset the
controller.
14. Slave configurationiscomplete,repeat this processforeach
Slave.
To Check an Existing Master UVC
1. Verify that the main power switch is at “Off.”
2. Set the network address.
For a master UVC, it is recommended that this hex switch
setting be “01”. (This is a “level 2” network address.) For
further information, refer to “Hex Switches” in the
“Component Data” section of this manual.
3. Apply power to the unit.
Turn the main power switch to “On” and the motor speed
switch to desired speed.
4. Check the status LED and operating mode changeover
devices.
The status LED should illuminate after calibration. If a wall
sensorpackageisused,theremote status LED should also
illuminate.
Referring to Table 1, verify that the day-night changeover
and tenant override options (if present) are working
properly. Do this by switching these devices and observing
the status LED.

Certified Drawing
IM 613 / Page 15 (Rev. 7/99)
5. Check for proper voltage levels at the Comm B port.
Use a DC voltmeter to test the voltage levels at the Comm
B terminals with respect to ground. The terminals and
acceptable voltage ranges are specified in Table 8.
If the voltage levels are acceptable, connect the IDC
connector to the Comm B port.
If no voltage or improper voltage levels are found, the UVC
is defective and must be replaced.
6. Verify that the unit ventilatorisoperatinginaccordancewith
its sequence of operation as outlined in the appropriate
documentation (refer toTable 6).
Since the sensed temperatures are fixed at any given
moment, adjust the room setpoint and unoccupied offset
pots to obtain the expected heating or cooling control
actions. If a PC is available, adjust any other applicable
parameters to obtain the expected UVC control actions.
7. Check for remote setpoint adjustment pot operation (if
present). Verify that the expected UVC control action
occurs when the remote pot is adjusted up or down.
8. Check that the ventilation lockout option works properly
(if present).
When the unit is in the occupied operating mode, verify
that the OA damper closes when the ventilation lockout
relay is energized.
Verify that the OA damper opens when the exhaust fan
interlock relay is energized.
9. Check that the fan interlock option works properly (if
present).
Verify that the OA damper opens when the exhaust fan
interlock relay is energized.
To Check Existing Slave UVC
1. Verify that the main power switch is at “Off.”
2. Set the network address.
Each slave must have a unique hex address. Begin by
setting the first slave’s address to “01.” (This is a “level 3”
network address.) Address each subsequent Slave in
consecutive order (02, 03, 04, 05). For further information,
refer to “Hex Switches” in the “Component Data” section of
this manual.
3. Apply power to the unit.
Turn the main power switch to “On” and the motor speed
switch to desired speed, wait 5 minutes until calibration is
complete.
4. Check the status LED.
The status LED should illuminate after calibration. If a wall
sensorpackageisused,theremote status LED should also
illuminate.
Verify that the slave’s status LED indication matches the
master’s indication, regardless of the operating mode.
If the status LED is flashing in a 16-blink sequence, the
slave is not communicating with its master. Refer to “Test
Procedures” in the “Service Information” section of this
manual.
5. Check for proper voltage levels at the Comm B port.
Usea DC voltmeter to test thevoltagelevels at the Comm B
terminals with respect to ground. The terminals and accept-
able voltage ranges are specified in Table 8.
If the voltage levels are acceptable, go on to step 6.
If no voltage or improper voltage levels are found, the UVC
is defective and must be replaced.
6. Check for proper voltage levels at the communication port
IDC connector.
Use a DC voltmeter to test the voltage levels at the
connector terminals with respect to ground. Test at the
connector terminals corresponding to the communication
port terminals listed in Table 8. Verify that the voltages are
within the ranges specified in the table.
If the voltage levels are acceptable, connect the IDC
connector to the Comm B port.
Ifno voltage or improper voltage levelsarefound, verify that
the master UVC is energized and that the communications
trunk wiring is intact.
7. Verify that the unit ventilator is operating in accordance with
its sequence of operation as outlined in the appropriate
documentation (refer toTable 6).
Since the sensed temperatures are fixed at any given
moment, adjust the UVC heating and cooling setpoints to
obtain the expected heating or cooling control actions. This
can be accomplished either by adjusting the pots at the
master or by disconnecting the communications cable and
adjustingthe pots at the slave. (Ifthelatter option is chosen,
be aware that the status LED will indicate a 16-blink
communication failure alarm.)
If a PC is available, adjust any other applicable parameters
(at the slave) to obtain the expected UVC control actions.
8. Check that the ventilation lockout option works properly
(if present).
When the unit is in the occupied operating mode, verify that
the CA damper closes when the ventilation lockout relay is
energized.
9. Check that the exhaust fan interlock option works properly
(if present).
Verify that the CA damper opens when the exhaust fan
interlock relay is energized.

IM 613 / Page 16 (Rev. 7/99)
Network
Prior to the start-up of any Network Unit Ventilator Controllers,
thefollowingMicroTech network devices mustbecommissioned:
• IBM compatible PC with Monitor software
• Network Master Panel
• Local Master Panel (as applicable)
• Loop Water Controller (as applicable)
Refertotheliteraturesuppliedwiththeseproductsforinformation
on installing and commissioning them.
After these devices have been properly commissioned, the
network UVC’s may be started in any order. However, if the start-
up order follows the daisy chain from one UVC to the next, it will
be easier to detect any wiring problems that may exist in the
communications trunk.
Communications Cable Check
Perform this check for every communications trunk connected to
a Network Master Panel (NMP) or Local Master Panel (LMP).
1. Be sure that the communication port IDC connectors are
disconnected at every UVC on the trunk.
2. Check that there are no shorts between any two conductors
in the communications trunk.
Use an ohmmeter to test for shorts at the communication
port IDC connector of the NMP or LMP. (For the three
combinations of conductor pairs, there should be infinite
resistance between the conductors.) If the conductors are
properly terminated, this check will test for shorts through-
out the trunk.
Procedure for Each Network UVC
1. Verify that the main power switch is at “Off.”
2. Set the network address.
Each UVC on an NMP or LMP trunk must have a unique
hex address. This address should be specified in the job
submittaldrawings.Referto the submittal drawings and set
the address in accordance with them. (This is a “level 3”
network address.) For further information, refer to “Hex
Switches” in the “Component Data” section of this manual.
3. Apply power to the unit.
Turn the main power switch to “On” and the motor speed
switch to either desired speed, wait 5 minutes until calibra-
tion is complete.
4. Check the status LED.
The status LED should illuminate after calibration. If a wall
sensorpackageisused,theremote status LED should also
illuminate.
5. Check for proper voltage levels at the Comm B port.
Use a DC voltmeter to test the voltage levels at the Comm
B terminals with respect to ground. The terminals and
acceptable voltage ranges are specified in Table 8.
If the voltage levels are acceptable, go on to step 6.
If no voltage or improper voltage levels are found, the UVC
is defective and must be replaced.
6. Check for proper voltage levels at the communication port
IDC connector.
Use a DC voltmeter to test the voltage levels at the
connector terminals with respect to ground. Test at the
connector terminals corresponding to the communication
port terminals listed in Table 8. Verify that the voltages are
within the ranges specified in the table.
If the voltage levels are acceptable, connect the IDC
connector to the Comm B port.
If no voltage or improper voltage levels are found, verify
thatthe NMPor LMPis energized and thatthecommunica-
tions trunk wiring is intact.
7. Verify that network communications between the UVC and
the NMP have initiated.
At the network PC, change the operating mode to
unoccupied and check that the status LED responds
accordingly.
8. Verify that the unit ventilatorisoperatinginaccordancewith
its sequence of operation as outlined in the appropriate
documentation (refer toTable 6).
Since the sensed temperatures are fixed at any given
moment, adjust the UVC heating and cooling setpoints (at
the network PC) to obtain the expected heating or cooling
control actions.
Adjust any other applicable parameters to obtain the
expected UVC control actions.
9. Check that any desired network-executed control features
are working properly (ventilation lockout, demand limiting,
etc.).
10. Review the submittal drawings and make any necessary
changes to the default UVC setpoints and parameters.
11. Check the remote setpoint adjustment pot operation
(if present).
Verify that the expected UVC control action occurs when
the remote pot is adjusted up or down.
12. Check that the exhaust fan interlock option works properly
(if present).
Verify that the OA damper opens when the exhaust fan
interlock relay is energized.

Certified Drawing
IM 613 / Page 17 (Rev. 7/99)
PC Access
A PC equipped with Monitor software is required for master or
slave UVC start-up. For further information, refer to “PC
Connection” in the “Service Information” section of this manual.
Communications Cable Check
1. Be sure that the communication port IDC connectors are
disconnected at every UVC on the network.
2. Check that there are no shorts between any two conduc-
tors in the communications trunk.
Use an ohmmeter to test for shorts at the communication
port IDC connector of the Master UVC. (For the three
combinations of conductor pairs, there should be infinite
resistance between the conductors.) If the conductors are
properly terminated, this check will test for shorts through-
out the network.
Use an ohmmeter to test for shorts at the communication port
IDC connector of the NMP or LMP. (For the three combinations
of conductor pairs, there should be infinite resistance between
the conductors.) If the conductors are properly terminated, this
check will test for shorts throughout the trunk.
Procedure for Each Network UVC
1. Verify that the main power switch is at “Off.”
2. Set the network address.
Each UVC on an NMP or LMP trunk must have a unique
hex address. This address should be specified in the job
submittaldrawings.Referto the submittal drawings and set
the address in accordance with them. (This is a “level 3”
network address.) For further information, refer to “Hex
Switches” in the “Component Data” section of this manual.
3. Apply power to the unit.
Turn the main power switch to “On” and the motor speed
switch to either desired speed, wait 5 minutes until calibra-
tion is complete.
4. Check the status LED.
The status LED should illuminate after calibration. If a wall
sensorpackageisused,theremote status LED should also
illuminate.
5. Check for proper voltage levels at the Comm B port.
Use a DC voltmeter to test the voltage levels at the Comm
B terminals with respect to ground. The terminals and
acceptable voltage ranges are specified in Table 8.
If the voltage levels are acceptable, go on to step 6.
If no voltage or improper voltage levels are found, the UVC
is defective and must be replaced.
6. Check for proper voltage levels at the communication port
IDC connector.
Use a DC voltmeter to test the voltage levels at the connector
terminals with respect to ground. Test at the connector
terminals corresponding to the communication port terminals
listedinTable8.Verifythat thevoltagesarewithin theranges
specified in the table.
If the voltage levels are acceptable, connect the IDC
connector to the Comm B port.
If no voltage or improper voltage levels are found, verify
that the NMP or LMP is energized and that the
communications trunk wiring is intact.
7. Verify that network communications between the UVC and
the NMP have initiated.
At the network PC, change the operating mode to
unoccupied and check that the status LED responds
accordingly.
8. Verify that the unit ventilatorisoperatinginaccordancewith
its sequence of operation as outlined in the appropriate
documentation (refer toTable 6).
Since the sensed temperatures are fixed at any given
moment, adjust the UVC heating and cooling setpoints
(at the network PC) to obtain the expected heating or cooling
controlactions.
Adjust any other applicable parameters to obtain the
expected UVC control actions.
9. Check that any desired network-executed control features
are working properly (ventilation lockout, demand limiting,
etc.).
10. Review the submittal drawings and make any necessary
changes to the default UVC setpoints and parameters.
11. Check the remote setpoint adjustment pot operation
(if present).
Verify that the expected UVC control action occurs when
the remote pot is adjusted up or down.
12. Check that the exhaust fan interlock option works properly
(if present).
Verify that the OA damper opens when the exhaust fan
interlock relay is energized.

IM 613 / Page 18 (Rev. 7/99)
Status LED Alarm Description Unit Ventilator Model
Blinks (Fault) Trigger Factory Setting Fault Reset
(Priority ` (Clear) AED AZS ARQ AVS AHF
AEQ AZQ ERQ AVV AHV
● ● ● ● ●
● ● ●
●● ●● ●●
●
● ●● ● ●● ●●
●● ●● ●●
● ● ● ●● ●●
●● ●●
●● ●● ●●
● ● ● ● ●
● ● ● ● ●
● ● ● ● ●
●● ●● ●● ●● ●●
●● ● ●● ●●
● ● ● ● ●
● ● ● ● ●
2 Room Temperature Sensor Failure Software Outside Range:
0.39 to 4.88 VDC (±4%)
3 High Pressure Hardware Opens at 400 ±10 psig 2-Auto resets
(HP) Closes at 300 ±20 psig within 7-days
then Manual
3 Low DX Coil Temperature (Units with Wet Heat) Hardware Opens at 30 ±4°F 2-Auto resets
(T4) Closes at 50 ±6°F within 7-days
then Manual
4 Low Refrigerant Temperature (Water Coil) Hardware Standard Range: 2-Auto resets
(T2) Opens at 36 ±3°F within 7-days
Closes at 46 ±2°F then Manual
Extended Range & Ground
Opens at 25 ±3°F
Closes at 35 ±2°F
5 Low DX Coil Temperature (Units without Wet Heat) Hardware Closes at 30 ±4°F 2-Auto resets
(T4) Opens at 50 ±6°F within 7-days
then Manual
5 Low Water Coil Leaving Air Temperature Hardware Closes at 38 ±2°F
(T6) Opens at 45 ±2°F Auto
6 Brownout Software Line Voltage < 85% Auto
of Nameplate Voltage (after 5 min)
7 Heating Valve Position Feedback Failure Software Outside Range:
0.2 ±0.1 to 3.68 ±0.29 VDC Auto
8 Valve or F&BPDamper Position Feedback Failure Software Outside Range:
0.2 ±0.1 to 3.68 ±0.29 VDC Auto
9 OA Damper Position Feedback Failure Software Outside Range:
` 0.2 ±0.1 to 3.68 ±0.29 VDC Auto
10 Discharge Air Temperature Sensor Failure Software Outside Range:
0.39 to 4.88 VDC (±4%) Auto
11 Outdoor Air Temperature Sensor Failure Software Outside Range:
0.39 to 4.88 VDC (±4%) Auto
12 Mixed Air Temperature Sensor Failure Software Outside Range:
0.39 to 4.88 VDC (±4%) Auto
13 Water-In Temperature Sensor Failure Software Outside Range:
0.39 to 4.88 VDC (±4%) Auto
15 Change Filter (Network Units Only) Software Fan Runtime Setpoint, Adj. Network
16 Communication Error (Master/Slave Only) Software N/A Auto
Diagnostics & Service
Table 9. Alarm and Fault Code Summary
Alarm is available for this unit.
Alarm may be available, depending on unit configuration.
●
●●
fault is present at a time, the status LED will indicate the one with
the highest priority. As the higher priority faults are cleared, the
lower priority faults will be indicated.
The UVC will simultaneously respond to multiple faults with the
appropriate control actions. If the programmed control actions of
multiple faults are contradictory, the higher priority fault actions
will occur. For example, assume that the 5-blink “low water coil
temperature” and 7-blink “heating valve position feedback
failure” faults exist concurrently. When the feedback failure fault
occurs, UVC control of the heating valve outputs is programmed
to cease (the valve would then hold its position). When the low
coiltemperaturefault occurs, the heating valve is programmedto
modulate to 25% open. In this situation, the 5-blink low coil
temperaturealarm has higherpriority.Therefore,the heating valve
will be opened. (Since there is no reliable feedback, the valve
could possibly open past the 25% setpoint.)
Clearing Faults
Beforeanyfault can be cleared, the alarm conditionsthatcaused
it must have returned to normal. When the alarm conditions are
gone, a fault may be cleared either automatically or manually.
Refer to Table 9.
Alarm Monitoring & Control
The Unit Ventilator Controller (UVC) is programmed to monitor
the unit ventilator for specific alarm conditions that may occur on
the various model types. If an alarm condition exists and is
| detected by the UVC, a “fault” will occur. The UVC will indicate
the fault and execute appropriate control actions for the alarm
conditions. For most faults, these actions will fail-safe the unit
ventilator.
Fault Code Interpretation
UVC faults are indicated at the status LED (on-board or remote).
If a fault exists, operating mode indication will be replaced by an
alarm-specific fault indication, the fault code.
Afault code is a seriesof blinks followed by a one-secondpause.
The number of blinks identifies the alarm condition as shown in
Table 9. The fault code sequence will repeat continuously until
the fault is cleared.
Priority and Multiple Alarms
Faults are ranked in order of their priority. Higher priority faults
havelower fault code blink counts (seeTable 9).Ifmore than one

Certified Drawing
IM 613 / Page 19 (Rev. 7/99)
An auto reset fault will immediately clear whenever the alarm
conditions that caused it disappear.
Amanual reset fault can be cleared by cycling power to the con-
troller.
Note: The cause of a manual reset fault should be investigated
andeliminated before the unit is placed back into service.
Alarm Descriptions
Following are descriptions of the various faults listed in Table 9.
Note that some alarms are present only on certain unit ventilator
model types and configurations.
2-Pipe Units Only: All references to heating or cooling valves
(modulating or EOC) in the “Effects” sections below also apply to
2-pipe units. Whether the 2-pipe valve is a “heating” or “cooling”
valve is determined by the entering water temperature. The
changeover setpoint is 80°F (default).
RoomTemperature Sensor Failure
The “Room Temperature Sensor Failure” fault will occur when
the voltage across the sensor is outside the acceptable range.
Refer to “Test Procedures” in the “Service Information” section of
this manual for information on troubleshooting sensor faults.
Effects (as applicable):
• Fan is immediately de-energized.
• Compressor is immediately de-energized.
• Reversing valve is de-energized after a delay.
• Outside air damper is closed.
• All electric heat stages are de-energized.
• Face and bypass damper is positioned to 100% face.
• Heating valve is fully opened to the coil.
• Chilled water valve is closed to the coil.
• Heating EOC valve is opened.
• Cooling EOC valve is closed.
High Pressure
The “High Pressure” fault is an indication that the high pressure
switch input (DI-4) sensed an open circuit while the controller
was calling for the compressor to run.
The high pressure switch (HP) is wired in series with the
compressor relay output (RO-2), the compressor relay coil (R1),
and the UVC alarm input. Therefore, if a high pressure condition
occurs, the compressor will be immediately shut down by the
switch; then it will be disabled by the UVC. Refer to “Test
Procedures” in the “Service Information” section of this manual
for information on troubleshooting digital input faults.
AV/AH Units Only: Because compressorized AV or AH models
are split systems, a factory-mounted high pressure switch is not
possible, and the high pressure fault is not available. On some of
these models, DI-4 is directly connected to 24 VAC to simulate a
no-fault condition.
AZ Units with Wet Heat: Note that a 3-blink fault code could be
either a high pressure or low DX coil temperature alarm.
Effects (as applicable):
• Compressor is immediately de-energized.
Low DX CoilTemperature (3-Blink Fault Code)
The 3-blink “Low DX Coil Temperature” fault is an indication that
the low temperature switch input (DI-4) sensed an open circuit
while the controller was calling for the compressor to run.
The low DX coil temperature switch (T4) is wired in series with
the compressor relay output (RO-2) and the UVC alarm input.
Switch T4 will open when the coil temperature falls below its
setpoint. Refer to “Test Procedures” in the “Service Information”
section of this manual for information on troubleshooting digital
input faults.
AZ Units withWet Heat: Note that a 3-blink fault code could be
either a low DX coil temperature or high pressure alarm.
Effect:
• Compressor is immediately de-energized.
Low RefrigerantTemperature (Water Coil)
The “Low Refrigerant Temperature” fault will occur when the
water source heat pump is in the heating mode and the
refrigerant temperature is at or below the low limit setpoint.
Usually, a low refrigerant temperature condition is caused by in-
sufficient water flow.
Effects:
• Compressor is immediately de-energized.
• Reversing valve is immediately de-energized.
Low DX CoilTemperature (5-Blink Fault Code)
The 5-blink “Low DX Coil Temperature” fault is an indication that
the low temperature switch input (DI-5) sensed a contact closure
while the
controller was calling for compressorized cooling. (UVC’s on air
source heat pumps in the defrost cycle will ignore this alarm con-
dition.)
The low DX coil temperature switch (T4) is connected
between 24 VAC and the UVC alarm input. Switch T4 will close
when the coil temperature falls below its setpoint. Refer to “Test
Procedures” in the “Service Information” section of this manual
for information on troubleshooting digital input faults.
Effect:
• Compressor is immediately de-energized.
LowWater Coil Leaving Air Temperature
The “Low Water CoilTemperature” fault is an indication that the
low temperature switch input (DI-5) is sensing a contact closure.
The low water coil temperature fault can occur at any time,
regardless of the Control Temperature or operating mode.
The low water coil temperature switch (T6) is connected
between 24 VAC and the UVC alarm input. Switch T6 will close
when the coil temperature falls below its setpoint. Refer to “Test
Procedures” in the “Service Information” section of this manual
for information on troubleshooting digital input faults.
Note: On 2-pipe valve controlled units, the entering water
temperature determines whether the valve will be enabled for
heating.It must be greaterthan80°F(default),otherwisethe valve
will be closed.
Effects (as applicable):
• Outdoor air damper is closed (exhaust fan interlock
feature is overridden).
• Heating valve is positioned to 100% open to the coil
(discharge air temperature < 55°F, default).
• Heating valve is positioned 25% open to the coil
(discharge air temperature ≥55°F, default).
• Chilled water valve is closed to the coil.
• Compressor is immediately de-energized.
• First stage of electric heat is energized (only if fan is on).

IM 613 / Page 20 (Rev. 7/99)
Brownout
The “Brownout” fault indicates that the UVC is sensing low
voltage levels. It is a safety that is intended to protect the
compressor and electric heat contactors from low line voltage or
“brownout”conditions.
The controller is programmed with a brownout setpoint that
corresponds to 85% of the unit ventilator’s nameplate line
voltage value. If the UVC senses a voltage level less than its
setpoint for more than 10 seconds (2 seconds with electric heat),
itwill triggerthebrownoutfault.Thefault willresetwhen thesensed
voltage remains at or above a level corresponding to 90% of the
nameplate value for a period of 5 minutes. For information on
troubleshooting this alarm, refer to “Test Procedures” in the
“Service Information” section of this manual.
Effects (as applicable):
• Compressor is immediately de-energized.
• All electric heat stages are immediately de-energized.
HeatingValve Position Feedback Failure (4-Pipe Units Only)
The “Heating Valve Position Feedback Failure” fault is an
indication that the UVC is sensing a valve position feedback
voltage that is outside the acceptable range. Refer to “Test
Procedures” in the “Service Information” section of this manual
for information on troubleshooting actuator feedback faults.
Effect:
• Heating valve will hold its position.
Valve or Face and Bypass Damper Position Feedback Failure
The “Valve or F&BP Damper Position Feedback Failure” fault is
an indication that the UVC is sensing a valve or F&BP damper
position feedback voltage that is outside the acceptable range.
Refer to “Test Procedures” in the “Service Information” section of
thismanual for information on troubleshooting actuatorfeedback
faults.
On 4-pipe valve controlled units, this fault applies to the chilled
water valve. On all other units with control valves or F&BP
dampers, there is only one possibility: heating valve, chilled
water valve, or F&BP damper actuator.
Effect:
• Valve or actuator will hold its position.
Outdoor Air Damper Position Feedback Failure
The “Outdoor Air Damper Position Feedback Failure” fault is an
indication that the UVC is sensing a damper position feedback
voltage that is outside the acceptable range. Refer to “Test
Procedures” in the “Service Information” section of this manual
for information on troubleshooting actuator feedback faults.
Effect:
• Outdoor air damper will hold its position.
Discharge AirTemperature Sensor Failure
The “Discharge Air Temperature Sensor Failure” fault will occur
when the voltage across the discharge air sensor is outside the
acceptable range. Refer to “Test Procedures” in the “Service
Information” section of this manual for information on trouble-
shooting sensor faults.
Effects (as applicable):
• Control Temperature is set equal to the room temperature.
• Discharge air low limit functions are disabled.
• Discharge air high limit function is disabled.
• All other control processes execute normally (discharge air
temperature is assumed to be acceptable).
Outdoor AirTemperature Sensor Failure
The“OutdoorAirTemperatureSensorFailure” faultwilloccur when
the voltage across the outdoor air sensor is outside the
acceptable range. Refer to “Test Procedures” in the “Service
Information” section of this manual for information on trouble-
shooting sensor faults.
Effects (as applicable):
• Economizer cooling is disabled (ventilation cooling lockout
function assumes OA temperature is high).
• Compressorized cooling is disabled on all except AR unit
(low ambient compressor lockout function assumes OA
temperature is low).
• On ASHP units, electric heat can be enabled by the
emergency heat, defrost, or discharge air low limit
functions only (OA temperature is assumed to be high).
• Heating EOC valve is controlled by room temperature only
(OA temperature is assumed to be high).
Water-InTemperature Sensor Failure
The “Water-In Temperature Sensor Failure” fault is applicable to
WSHP units and to units equipped with water coils (except for
4-pipevalve controlled units). It will occurwhenthevoltageacross
the entering water temperature sensor is outside the acceptable
range. Refer to “Test Procedures” in the “Service Information”
section of this manual for information on troubleshooting sensor
faults. Note: Except for 2-pipe units, this fault will not affect the
normal operation of units equipped with water coils.
Effects (as applicable toWSHP units):
• Economizer changeover function depends on OA
temperature only (entering water temperature is assumed
to be high).
• Compressorized heating is available (entering water
temperature is assumed to be high).
• Electric heat can be enabled by the emergency heat or
discharge air low limit functions only (entering water
temperature is assumed to be high).
Effects (as applicable to 2-pipe units):
• Valve or face and bypass damper cooling operation is
disabled (entering water temperature is assumed to be
high).
• EOC valve will act as a heating EOC valve (entering water
temperature is assumed to be high).
Water-OutTemperature Sensor Failure
The“Water-OutTemperatureSensor Failure” fault will occur when
the voltage across the leaving water temperature sensor is
outside the acceptable range. Refer to “Test Procedures” in the
“Service Information” section of this manual for information on
troubleshooting sensor faults.