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