McQuay MicroTech II Troubleshooting guide

MicroTech II™ Unit Ventilator Controls
for AAF®-HermanNelson®Classroom Unit Ventilators
Operation Maintenance Manual OM 750
Group: Unit Ventilator
Part Number: 106506303
Date: August 2002
Supercedes: New
©2002 AAF®-HermanNelson®
Used with AAF-HermanNelson Classroom Unit Ventilator
Model AVV, AVR – Floor Mounted
Model AHV, AHR – Ceiling Mounted
Model AZV, AZU, AZR – Floor Mounted Self Contained Air Conditioner
Before unit commissioning, please read this publication in its entirety.
Develop a thorough understanding before starting the commissioning procedure.
This manual is to be used by the commissioner as a guide. Each installation is unique, only general topics are covered.
The order in which topics are covered may not be those required for the actual commissioning.
IMPORTANT
DX Cooling with Electric Heat – Software Model UV04

Page 2 of 32 OM 750
TABLE OF CONTENTS
Abbreviations Table ......................................................... 3
Safety Information...........................................................4
Introduction ..................................................................5
Getting Started...............................................................5
Using the Local User Interface (LUI) ............................................. 5
2-digit 7-segment display........................................................ 5
On/Stop Button and LED ......................................................... 5
Fan Button ............................................................................... 6
Mode Button............................................................................ 6
Arrow Buttons ......................................................................... 6
Func Button ............................................................................. 6
Viewing Actual Temperature (IAT) ........................................... 6
Using the LUI to adjust Setpoint Offset ................................... 6
LUI Security Levels.................................................................. 6
Changing LUI Security Level.............................................. 6
Why can’t I use the Mode or Fan button,
or adjust Setpoint Offset?.................................................. 6
LUI Menu Reference...................................................................... 7
Changing an LUI Menu Item.............................................. 7
Description of Operation ................................................... 9
State Programming ....................................................................... 9
UVC Unit Modes .......................................................................... 10
Off Mode ............................................................................... 10
Night Purge Mode ................................................................. 10
Fan Only Mode....................................................................... 11
Emergency Heat Mode (Super State)..................................... 11
Full Heat State ................................................................. 11
Cant Heat State................................................................ 12
Auto Mode............................................................................. 12
Heat Mode (Super State) ....................................................... 12
Heat State ........................................................................ 13
Low Limit State ............................................................... 13
Cant Heat State................................................................ 13
Cool Mode (Super State) ....................................................... 14
Econ State ....................................................................... 15
Econ Mech State.............................................................. 15
Mech State ...................................................................... 16
Cant Cool State................................................................ 16
DA Heat State .................................................................. 16
Low Limit State ............................................................... 16
Active Dehumidify State (optional,
software model 04) ..................................................... 17
Special Purpose Unit Modes.................................................. 17
Pressurize Mode.............................................................. 17
Depressurize Mode.......................................................... 17
Purge Mode..................................................................... 17
Shutdown Mode .............................................................. 17
Energy Hold Off Mode ..................................................... 17
UVC Unit Mode Priority ......................................................... 17
Occupancy Modes ....................................................................... 18
Occupied Mode...................................................................... 19
Unoccupied Mode.................................................................. 19
Standby Mode ....................................................................... 19
Bypass Mode......................................................................... 19
Networked Occupancy Sensor Capability .............................. 19
Unit-Mounted Time-Clock...................................................... 19
Unit-Mounted Tenant Override Switch ................................... 19
Remote Wall-Mounted Sensor Tenant
Override Switch ............................................................... 19
Remote Wall-Mounted Sensor Status LED ............................ 19
Space Temperature Setpoints ...................................................... 19
Networked Setpoint Capability............................................... 19
Networked Setpoint Offset Capability .................................... 19
Networked Setpoint Shift Capability ...................................... 19
Networked Space Temperature
Sensor Capability............................................................. 19
LUI Setpoint Offset Adjustment ............................................. 20
Remote Wall-Mounted Sensor with +/- 3°F
Adjustment (optional)...................................................... 20
Remote Wall-Mounted Sensor with 55°F to 85°F
Adjustment (optional)...................................................... 20
Effective Setpoint Calculation Examples ................................ 20
PI Control Loops ......................................................................... 21
Discharge Air Temperature Control........................................ 21
PI Control Parameters ........................................................... 22
Proportional Band ................................................................. 22
Integral Time ......................................................................... 22
Indoor Air Fan Operation ............................................................. 23
Auto Mode............................................................................. 23
Occupied, Standby and Bypass Operation ............................. 23
Unoccupied Operation ........................................................... 23
Cycle Fan ............................................................................... 23
Off Delay................................................................................ 23
Outdoor Air Damper Operation .................................................... 23
Minimum Position ................................................................. 23
Economizer Operation ........................................................... 23
Temperature Comparison Economizer............................. 23
Temperature Comparison with OA Enthalpy
Setpoint Economizer (optional) ................................... 23
Temperature Comparison with Enthalpy
Comparison Economizer (optional) ............................. 24
Networked Space Humidity Sensor Capability ....................... 24
Networked Outdoor Humidity Sensor Capability.................... 24
CO2Demand Controlled Ventilation (optional)....................... 24
Networked Space CO2Sensor Capability ............................... 24
ASHRAE Cycle II.................................................................... 24
Compressor Operation ................................................................ 24
Compressor Envelope............................................................ 24
Compressor Cooling Lockout ................................................ 25
Minimum On and Off Time .................................................... 25
Compressor Start Delay......................................................... 25
Outdoor Air Fan Operation..................................................... 25
Floating-point Actuator Auto-Zero, Overdrive and Sync............... 25
External Binary Inputs ................................................................. 25
External Binary Input 1 .......................................................... 25
Unoccupied Input Signal ................................................. 25
Dewpoint/Humidity Input Signal
(optional, software model 04) ..................................... 25
External Binary Input 2 .......................................................... 25
Remote Shutdown Input Signal....................................... 26
External Binary Input 3 .......................................................... 26
Ventilation Lockout Input Signal...................................... 26
Exhaust Interlock Input Signal......................................... 26
External Binary Outputs ............................................................... 26
External Binary Output 1........................................................ 26
Lights On/Off Signal ........................................................ 26
External Binary Output 2........................................................ 26
Fault Signal...................................................................... 26
External Binary Output 3........................................................ 26
Exhaust Fan On/Off Signal ............................................... 26

OM 750 Page 3 of 32
Index of Meaning of Abreviations
Abreviations
AHED Auxiliary Heat End Differential
AHSD Auxiliary Heat Start Differential
ASCII American Standard Code for Information Interchange
ASHRAE American Society of Heating, Refrigerating,
and Air Conditioning Engineers, Inc
CCLO Compressor Cooling Lockout Setpoint
CO2S CO2Setpoint
CW Chilled Water
CWVP Chilled Water Valve Position
DA Discharge Air
DAHL Discharge Air High Limit
DAT Discharge Air Temp
DATS Discharge Air Temp Setpoint
DCV Demand Controlled Ventilation
ECD Economizer Compare Differential
EED Economizer Enthalpy Differential
EES Economizer Enthalpy Setpoint
EHS Emergency Heat Setpoint
EOAD Exhaust Outdoor Air Damper
EOAT Outdoor Air Temperature Output
EOC End-of-Cycle
EOCS End-of-Cycle Low OAT Setpoint
EORH Outdoor Air Humidity Output
ERH Space Humidity Output
ETD Economizer Temperature Differential
ETS Economizer Temperature Setpoint
EWIT Source (Water-in) Temperature
FBDP Face and Bypass Damper Position
FCC Federal Communications Commission
F & BP Face & Bypass
HVACR Heating, Ventilating, Air Conditioning, Refrigerating
HW Hot Water
IA Indoor Air
IAF Indoor Air Fan
IAT Indoor Air Temperature
UVC Input and Output Table.............................................. 27
Diagnostics and Service.................................................. 27
Alarm and Fault Monitoring ......................................................... 27
Space Temp Sensor Failure ................................................... 28
DX Pressure Fault.................................................................. 28
Compressor Envelope Fault ................................................... 28
Discharge Air DX Cooling Low Limit Indication ..................... 28
Condensate Overflow Indication (optional)............................ 28
Space Coil DX Temp Sensor Failure....................................... 28
Outdoor Temp Sensor Failure ................................................ 28
Table 1. Abbreviations
Index of Meaning of Abreviations
Abreviations
LED Light Emitting Diode
LUI Local User Interface
MCLL Mechanical Cooling Low Limit
NEC National Electrical Code
OA Outdoor Air
OAD Outdoor Air Damper
OADE Energize Exhaust Fan OAD Setpoint
OADH OAD Min Position High-Speed Setpoint
OADL OAD Min Position Low-Speed Setpoint
OADM OAD Min Position Medium-Speed Setpoint
OADP Outdoor Air Damper Position
OALS Outside Air Lockout Position
OAMX OAD Maximum Position Setpoint
OAT Outdoor Air Temperature
OCS Occupied Cooling Setpoint
OHS Occupied Heating Setpoint
PI Proportional Integral
PPM Parts Per Million
RH Relative Humidity
RHS Space Humidity Setpoint
RO Read Only
RW Read Write
SCS Standby Cooling Setpoint
SHS Standby Heating Setpoint
TXV Thermal eXpansion Value
UCS Unoccupied Cooling Setpoint
UHS Unoccupied Heating Setpoint
UV Unit Ventilator
UVC Unit Ventilator Controller
UVCM UVC (Heat/Cool) Mode Output
UVCS UVC State Output
VALP Wet Heat Valve Position
VCLL Ventilation Cooling Low Limit
WH Wet Heat
WITD Source (Water-in) Temperature Differential
Discharge Air Temp Sensor Failure........................................ 28
Outdoor Coil DX Temp Sensor Failure ................................... 28
Space Humidity Sensor Failure (optional) ............................. 28
Outdoor Humidity Sensor Failure (optional) .......................... 28
Space CO2Sensor Failure (optional)...................................... 29
Change Filter Indication ......................................................... 29
Troubleshooting Temperature Sensors ........................................ 29
Troubleshooting Humidity Sensors ............................................. 29
Troubleshooting Carbon Dioxide (CO2) Sensors .......................... 29
UVC Configuration Parameters.......................................... 30

Page 4 of 32 OM 750
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.
Follow all safety codes. Wear safety glasses and work gloves. Use a
quenchingclothforbrazingoperations.Haveafireextinguisheravailable.
Follow all warnings and cautions in these instructions and attached to
theunit. Consultapplicable localbuilding codesand NationalElectrical
Codes (NEC) for special requirements.
Recognize safety information. When you see a safety symbol on the
unit or in these instructions, be alert to the potential for personal injury.
Understand the meanings of the words DANGER, WARNING, and
CAUTION.DANGERidentifiesthemostserioushazardsthat willresult
DISCONNECT ALL ELECTRICAL
POWERBEFORESERVICINGUNIT
TO PREVENT INJURY OR DEATH
DUE TO ELECTRICAL SHOCK.
WARNING
HAZARDOUS VOLTAGE!
DISCONNECT ALL ELECTRIC POWER IN-
CLUDINGREMOTE DISCONNECTSBEFORE
SERVICING. FAILURE TO DISCONNECT
POWER BEFORE SERVICING CAN CAUSE
SEVERE PERSONAL INJURY OR DEATH.
!CAUTION
USE COPPER CONDUCTORS ONLY.
UNIT TERMINALS ARE NOT DESIGNED TO
ACCEPT OTHER TYPES OF CONDUCTORS.
FAILURE TO DO SO MAY CAUSE DAMAGE
TO THE EQUIPMENT.
!
!DANGER
NOTICE
WARNING
!
WARNING
!
CAUTION
!
CAUTION
!
Staticsensitivecomponents.Astaticdischargewhilehandling
electronic circuit boards can cause damage to the
components.
Discharge any static electrical charge by touching the bare metal
inside the main control panel before performing any service work.
Never unplug any cables, circuit board terminal blocks, relay
modules, or power plugs while power is applied to the panel.
Extreme temperature hazard can cause damage to system
components.
This MicroTech II controller is designed to operate in ambient
temperatures from -40°F to 158°F. It can be stored in ambient
temperatures from -65°F to 176°F. The controller is designed to
operate in a 10% to 90% RH (non-condensing) and be stored in a
5% to 95% RH (non-condensing) environment.
in death or severe personal injury; WARNING means the hazards can
result in death or severe personal injury; CAUTION identifies unsafe
practices that can result in personal injury or product and property
damage.
Improper installation, adjustment, service, maintenance, or use can
cause explosion, fire, electrical shock, or other conditions which may
result in personal injury or property damage. This product must be
installed only by personnel with the training, experience, skills, and
applicable licensing that makes him/her “a qualified professional
HVACR installer.”
SAFETY INFORMATION
This equipment generates, uses, and can radiate radio frequency
energy and, if not installed and used in accordance with this
instructionmanual,maycauseinterferencetoradiocommunications.
It has been tested and found to comply with the limits for a Class A
digitaldevice,pursuanttopart15oftheFCCrules.Theselimitsare
designed to provide reasonable protection against harmful
interference when the equipment is operated in a commercial
environment. Operation of this equipment in a residential area is
likely to cause harmful interference in which case the user will be
required to correct the interference at his own expense.
McQuay®International disclaims any liability resulting from
any interference or for the correction thereof.
Electricshockhazard.Cancausepersonalinjuryorequipment
damage.
This equipment must be properly grounded. Connections and
servicetotheMicroTechIIcontrolpanelmustbeperformedonlyby
personnelthatareknowledgeableintheoperationoftheequipment
being controlled.
CAUTION
!
For proper space control, and a more trouble free unit operation, it
isimportantthatanoccupancycontrolmeansbeusedsuchthatthe
unit is placed into unoccupied mode during regular low load
conditions such as nighttime, weekends and holidays.
Hot Surface! Do not touch surface.
Can cause minor to severe burns.
WARNING
!
Hazardous Voltage! Disconnect all electric power before
servicing.
Failureto disconnectpower (includingremote disconnects)before
servicing can cause severe personal injury or death.
WARNING
!
Rotating Fan Blade! Disconnect all electric power before
servicing.
Failureto disconnectpower (includingremote disconnects)before
servicing can cause severe personal injury or death.
WARNING
!

OM 750 Page 5 of 32
Unit Ventilator Available Protocols Bulletin Number
Unit Ventilator Unit Controller LonWorks® Communications Module IM 729
Unit Ventilator Unit Controller JCI N2 Open® Communications Module IM 730
Unit Ventilator Unit Controller BACnet® Communications Module IM 731
Protocol Data Packet ED-15065
Unit Ventilator Installation
Model Designations Description Manual Bulletin
Number
AED, AEQ Air Source Heat Pump IM 502
ARQ, ERQ Water Source Heat Pump IM UV-3-202
AZS, AZQ, AZV, AZU, AZR Self-contained IM 503
AVS, AVV, AVR, AVB Vertical Split-system
AHF, AHV, AHR, AHB Horizontal Split-system IM 725
Unit Ventilator Control Configuration Bulletin Number
MicroTech II Unit Ventilator Controller IM 747
ManyUVCparametersareaccessibleboththroughtheLUIandthe
network interface. The shared LUI and the network interface
variables have a “last-change-wins” relationship.
2-DIGIT 7-SEGMENT DISPLAY
The LUI 2-digit 7-segment display normally will be displaying the
effective (current) heating or cooling setpoint (Effective Setpoint
Output). The LUI display is also used to view and adjust many UVC
parameters as explained in the following sections.
When the UVC is in the Off mode, the LUI will display the current
heating setpoint and all other LED’s will be switched off.
ON/STOP BUTTON AND LED
The On/Stop button is used to toggle the UVC between Off mode and
running(ApplicationModeInput).TheOn/StopLEDwillbeoffwhen
the UVC is in the off mode.
GETTING STARTED
ThismanualcontainsinformationregardingtheMicroTechII™control
system used in the AAF®-HermanNelson®Unit Ventilator product
line. It describes the MicroTech II components, input/output
configurations, field wiring options and requirements, and service
procedures.
For installation and general information on the MicroTech II Unit
Ventilator Controller, refer to the appropriate installation and
maintenance bulletin, see Table 2.
Table 3. Model-Specific Unit Ventilator Installation Literature
Table 2. MicroTech UVC Installation Literature
Using the Local User Interface (LUI)
The MicroTech II UVC is a self-contained device that is capable of
complete, stand-alone operation. Information in the controller can be
displayed and modified by using the Local User Interface (LUI). The
following sections describe how to use the LUI.
Table 4. Protocol-Specific Communication Card Installation Literature and Protocol Data
Figure 1. Local User Interface (LUI)
NOTICE
INTRODUCTION
For installation, commissioning instructions and general information
on a particular unit ventilator model, refer to the appropriate model-
specific installation manual, refer to Table 3.
For installation and manual instructions on a particular plug-in
communications card, refer to the appropriate protocol-specific
installation manual, see Table 4. For a description of supported
network variables for each protocol refer to Protocol Data Packet
bulletin, see Table 4.
NOTICE

Page 6 of 32 OM 750
The UVC archives each change to the LUI Fan and Mode buttons.
When the On/Stop button is used to bring the unit out of Off mode,
the UVC will implement the last active fan and unit modes.
Eachtime theUVCpoweriscycled, theUVC willbe inauto fanand
auto unit modes when power is returned.
FAN BUTTON
The Fan button is used to toggle through each of the Fan speeds (Fan
Speed Command Input): Auto, Low, Medium, and High.
MODE BUTTON
The Mode button is used to toggle through the LUI accessible unit
modes (Heat/Cool Mode Input): Auto, Heat, Cool, and Fan Only.
ARROW BUTTONS
The arrow buttons are used to scroll between and adjust parameters.
FUNC BUTTON
TheFuncbuttonisusedtoviewtheactualspacetemperature.TheFunc
button is also used as an ENTER key to confirm selection and changes
to user adjustable or viewable parameters.
VIEWING ACTUAL TEMPERATURE (IAT)
The LUI displays the setpoint temperature. The LUI can be used to
view the actual room temperature. See Figure 2. Two Digit What is Restricted? Password
Display
Level 0 Default level (access all) 10
Level 1 Do not allow user to adjust setpoint 21
Level 2 Do not allow user to adjust setpoint nor
make Mode button changes 32
Level 3 Do not allow user to adjust setpoint nor
make Mode and Fan button changes 43
Table 5. LUI Security Levels
Figure 4. Changing LUI Security Levels
WHY CAN’T I USE THE MODE OR FAN BUTTON,
OR ADJUST SETPOINT OFFSET?
Mostlikely this isdue tothe security featurebeing used.If the security
featureis sethigherthan level0, thensomeLUI functionalityis locked
out. To ensure this is not the problem, enter the level 0 password then
try again to use the LUI.
Whenusingthe+/-3°F(+/-1.7°C)remotewallsensor,anysetpoint
offset adjustment made at the LUI will cause the UVC to override
and ignore the remote wall sensor setpoint adjustment knob. To
again use the remote wall sensor setpoint adjustment knob, you
must clear the LUI setpoint offset adjustment by cycling UVC
power.
Figure 3. Adjusting the Setpoint Offset
NOTICE
NOTICE
NOTICE
NOTICE
NOTICE
LOCAL USER INTERFACE (LUI) SECURITY LEVELS
The LUI provides a 4-level password security feature which can be
used by owners to restrict LUI access.
The setpoint offset is cleared after every power cycle. When
changingthesetpointoffsetafterapowercycle,orforthefirsttime,
this cleared value will be shown as the highest allowed value (5°F
/ 3°C) but will not bean actual offset value.
Figure 2. Viewing Actual Temperature (IAT)
Whentheactualspacetemperature(EffectiveSpaceTempOutput)
equals the effective setpoint (Effective Setpoint Output) you will
seenochangetotheLUIdisplaywhenyouviewspacetemperature.
NOTICE
When using the 55OF to 85OF remote wall sensor, the UVC will
ignore any LUI setpoint offset adjustments.
USING THE LUI TO ADJUST SETPOINT OFFSET
The LUI can be used by room occupants to easily make +/- 5OF (+/-
3OC) adjustments to the effective temperature setpoint. See the Space
TemperatureSetpointssectiontolearnmoreabouttemperaturesetpoints.

OM 750 Page 7 of 32
LUI Menu Reference
TheLUImenueasestroubleshootingandsimplifiesUVCconfiguration
as the most common parameters and system status values can be
accessedwithouttheneedofaPersonalComputerornetworkinterface.
The LUI menu is accessed via an unmarked, Hidden button. This
Hidden button is located behind the letter “h” in the MicroTech II logo
on the LUI face.
The LUI menu consists of two levels. The first level is the LUI Menu
Item List containing alphanumeric characters which represent each
parameter. The second level is the level where the parameters value is
viewed, and can be adjusted if the parameter is adjustable. A 5-second
inactivity timer is used to automatically back out of the menu levels
until returning to the effective setpoint display. See figure 5 for
procedure to change LUI Menu Item.
Figure 5. Changing an LUI Menu Item
Table 6. LUI Menu Item List
Two Digit
Display LUI Menu Item List Abr. Description 햳04 Default
Enter 1 to clear alarms (clears all inactive alarms, except filter alarm).
Reset Alarm Input You must enter a 0 value after entering a 1 in order to re-enable the RW x 햲
alarm feature.
UVC (Heat/Cool) Mode Output UVCM Display current UVC mode. RO x
UVC State Output UVCS Display current UVC state. RO x
Discharge Air Temp Setpoint Output DATS Display current DA temperature setpoint. RO x
Discharge Air Temp Output DAT Display current DA temperature. RO x
Ventilation Cooling Low Limit Setpoint VCLL Adjust economizer cooling DA temperature low limit. RW x 54OF (12OC)
Mechanical Cooling Low Limit Setpoint MCLL Adjust mechanical cooling DA temperature low limit. This value can only RW x 45OF (7OC)
be displayed in degrees C.
Slave Type Configuration Set slave type: 0 = Independent (slave uses own sensors), RW x 0
1 = Dependent (slave follows master).
Effective Occupancy Output Display current occupancy: 0 = occupied, 1 = unoccupied, 2 = bypass, RO x
3 = standby.
Set occupancy: 0 = occupied, 1 = unoccupied, 2 = bypass, 3 = standby.
Occupancy Override Input Adjusting this variable is only intended for troubleshooting, once you RW x 햲
are done you must cycle unit power to clear this variable and return the
UVC to normal operation.
Occupied Cooling Setpoint OCS Adjust occupied cooling setpoint. RW x 73OF (23OC)
Standby Cooling Setpoint SCS Adjust standby cooling setpoint. RW x 77OF (25OC)
Unoccupied Cooling Setpoint UCS Adjust unoccupied cooling setpoint. RW x 82OF (28OC)
Occupied Heating Setpoint OHS Adjust occupied heating setpoint. RW x 70OF (21OC)
Standby Heating Setpoint SHS Adjust standby heating setpoint. RW x 66OF (19OC)
Unoccupied Heating Setpoint UHS Adjust unoccupied heating setpoint. RW x 61OF (16OC)
Wall Sensor Type Set wall sensor type: 0 = +/- 3°F, 1 = 55°F to 85°F. RW x 0
Outside Air Damper Position Output OADP Display OA damper position. RO x
Adjust OA damper minimum position with IAF at high speed. (this
OAD Min Position High-Speed Setpoint OADH variable will be factory set to 5% open when the unit is ordered with RW x 20%
optional CO2 DCV)
OAD Min Position Med-Speed Setpoint OADM Adjust OA damper minimum position with IAF at medium speed. (this RW x 30%
variable is ignored when the unit is ordered with optional CO2 DCV)
OAD Min Position Low-Speed Setpoint OADL Adjust OA damper minimum position with IAF at low speed. (this RW x 35%
variable is ignored when the unit is ordered with optional CO2 DCV)
Exhaust Interlock OAD Min Position EOAD Adjust OA damper minimum position when the exhaust interlock RW x 99%
Setpoint input is energized.
Energize Exhaust Fan OAD Setpoint OADE Adjust OA damper position above which the exhaust fan output will RW x 10%
be energized.
OAD Max Position Setpoint OAMX Adjust OA damper maximum position. RW x 99%
Set OA damper lockout feature status: 0 = disable, 1 = enable.
OAD Lockout Enable (this variable will be factory set to 1 when the unit is ordered RW x 0
as a recirc unit with no OAD)
Adjust OA temperature below which the OA damper will be closed
OAD Lockout Setpoint OALS if the OA damper lockout is enabled. (this variable will be factory set RW x 36OF (2OC)
to –99OC when the unit is ordered as a recirc unit with no OAD)
Continued on next page.

Page 8 of 32 OM 750
Table 6. LUI Menu Item List (Continued)
Economizer Enable Set economizer status: 0 = disable, 1 = enable. RW x 1
Economizer OA Temp Setpoint ETS Adjust economizer OA temperature setpoint. RW x 68OF (20OC)
Economizer IA/OA Temp Differential ETD Adjust economizer IA/OA temperature differential. RW x 2OF (1OC)
Adjust economizer IA/OA temperature differential. This variable is
Economizer Compare Differential ECD identical to Economizer IA/OA Temp Differential and therefore need RW x 0OF (0OC)
not be used (do not change).
Economizer OA Enthalpy Setpoint EES Adjust economizer OA enthalpy setpoint. RW x 25 btu/lb
(58 kJ/kg)
Economizer IA/OA Enthalpy Differential EED Adjust economizer IA/OA enthalpy differential. RW x 1 btu/lb
(3 kJ/kg)
Space Humidity Output ERH Display room humidity (optional). RO x
Space Humidity Setpoint RHS Adjust room humidity setpoint, for active dehumidification (optional). RW x 60%
Outdoor Air Humidity Output EORH Display OA humidity (optional). RO x
Outdoor Air Temp Output EOAT Display OA temperature. RO x
Emergency Heat Enable Set emergency heat status: 0 = disable, 1 = enable. RW x 1
Emergency Heat Setpoint EHS Adjust emergency heat setpoint. RW x 54OF (12OC)
Emergency Heat Shutdown Set emergency heat operation during shutdown,
0 = no emergency heat during shutdown: RW x 0
Configuration 1 = allow emergency heat during shutdown.
External BI-1 Configuration Set the function of external binary input 1: 0 = unoccupied, RW x 0
1 = dewpoint/humidity switch. 햴
External BI-3 Configuration Set the function of external binary Input 3: 0 = ventilation lockout, RW x 0
1 = exhaust interlock.
Fan Cycling Configuration Set if IAF cycles (switches off) during occupied, bypass, and RW x 2
standby mode: 2 = no cycling, 3 = cycle IAF.
Filter Alarm Enable Set filter alarm status: 0 = disable, 1 = enable. RW x 0
Reset Filter Alarm Input Enter 1 to clear filter alarm. You must go back and enter a 0 value RW x 햲
after entering a 1 to re-enable the filter alarm.
Compressor Enable Set compressor status: 0 = disable, 1 = enable. RW x 1
Compressor Cooling Lockout Setpoint CCLO Adjust compressor cooling lockout setpoint. When the OA tempera- RW x 61OF (16OC)
ture falls below this setpoint compressor cooling is not allowed.
Adjust compressor start delay. This setpoint should be changed
Compressor Start Delay for every UVC to prevent many compressors from energizing at the RW x 0 sec
same time after a power failure or occupancy change.
LUI Temperature Units Set LUI temperature display units in degrees F or degrees C. RW x F
햲If a menu item value is greater than 2-digits (higher than 99), then will be displayed by the LUI.
햳RW = read and write capable, RO = read only. (All RO values displayed are snapshots and are not dynamically updated as the value is displayed.)
햴Additional UVC field configuration is required if the dewpoint/humidity binary input is used, consult the factory.
Two Digit
Display LUI Menu Item List Abr. Description 햳04 Default

OM 750 Page 9 of 32
State Programming
TheMicroTechIIUVCtakesadvantageofstatemachineprogramming
to define and control unit ventilator operation. State machines define
specific states, or modes of operation for each process within the unit
ventilator (i.e. heating, cooling, etc.) and contain the specific logic for
each state. This eliminates some of the most common problems
associatedwithcontrolsequencessuchasthepossibilityofsimultaneous
heating and cooling, rapid cycling, etc.
State machine programming, and the unique nature of state diagrams,
can be easily used to describe unit ventilator operation, and can vastly
simplify sequence verification during unit commissioning, as well as
simplifytroubleshooting.Withtheuniquecombinationofstatemachine
programming and the LUI’s ability to allow a technician to easily
determine the active UVC state, troubleshooting the UVC can be very
simple.
The state diagrams presented in the following sections consist of
several “elements” including Super States, States, Conditional Jumps
(alsocalled transitions)anda TransitionPoint.Super statesare usedas
a means to group two or more related states into a single control
functionsuch as cooling,or heating, etc.States are where all theactual
worktakesplace,withineachstatetheUVCenablesPI-loopsandother
logicsequencesrequiredtocontrolunitventilatoroperationwithinthat
particular state, while other functions and PI-loops not needed during
that state may be disabled. Conditional jumps, or transitions, are the
Notall states ormodes are availablefor allUV configurations,and
some states (such as Active Dehumidification) are optional.
DESCRIPTION OF OPERATION
Figure 6. Complete UVC - State Program
In the state descriptions below the terms saturated high and
saturated low indicate that the heating or cooling function being
described has reached 100% or 0% respectively.
logic paths used by the UVC to determine which state should be made
active, these are the “questions” the UVC will continually consider.
The transition point is simply a point through which a number of
conditional jumps meet, you can think of it as a point where a number
of questions must be considered from which the UVC then determines
which path is followed and which state is then made active.
The UVC states and super states are used to define the “normal” unit
modes, such as Off, Night Purge, Fan Only, Emergency Heat, Auto,
Cool, Heat, and Active Dehum. The UVC also supports several
“specialpurpose”unitmodessuchasPurge,Pressurize,De-pressurize,
and Shutdown, which can be forced via a network connection and
override typical UVC operation.
NOTICE
NOTICE

Page 10 of 32 OM 750
Table 7. UVC State Names and Numbers (see figure 6)
State State
Normal UVC Modes Numbers
Names (ASCII)
Off Off 9(57)
Night Purge Night Purge 8(56)
Fan Only Fan Only A(65)
Emergency Heat Full Heat 7(55)
Super State Cant Heat D(68)
Heat 5(53)
Heat Cant Heat B(66)
Super State Low Limit E(69)
EconMech 1(49)
Auto Mech 2(50)
Cool Econ 3(51)
Super State DA Heat 4(52)
Cant Cool C(67)
Low Limit F(70)
Dehumidify 햲Active Dehum 6 (54)
햲Optional.
UVC Unit Modes
The UVC provides several “normal” modes of unit operation, these
include Off, Night Purge, Fan Only, Cool, Emergency Heat, Auto,
Heat and Cool.
Normal UVC modes can contain a single state or several states
dependent upon the functionality required for each particular mode.
EachUVC statehas beenassigned anumber. Thisstate numbercan be
very helpful when trying to understand which state is currently active
within the UVC. The current UVC state number can be viewed using
the LUI. See Figure 6 for Super State and State.
Transition (UVC Mode = Off)
into State
Operation When Off mode becomes active, the UVC stops all
within State normal heating, cooling, ventilation (OA damper is
closed), and fan operation. he UVC will continue to
monitor space conditions, indicate faults, and provide
network communications (if connected to a network)
as long as power is maintained to the unit. If the space
temperature drops below EHS, and the Emergency
Heat function is enabled, the UVC will be forced into
the Emergency Heat mode (see Emergency Heat Mode).
he space lighting output will continue to operate
normally based upon the current UVC occupancy
mode.
Special purpose unit modes (i.e. Purge, Pressurize,
and De-pressurize modes) accessed via a network
connection can force the UVC to perform “special”
functions during which the UVC will appear to be in
the Off mode. See Special Purpose Unit Modes, and
the UVC Unit Mode Priority sections for more
information.
he UVC will remain in this state until one of the
transition out conditions become true.
Transition (UVC Mode ≠ Off)
out of State
Figure 7. Off State Diagram
OFF MODE (STATE NUMBER 9)
Offmode is providedso that theUVC can be forced intoa powered off
condition.TheOffmode isa“stop”statefor theunitventilator,it is not
a power off state. The LUI or a network connection can force the unit
into the Off mode. Off mode consists of a single UVC state: Off [9].
WARNING
!
Offmode isa“stop” statefor theunitventilator. Itis nota“power
off” state. Power may still be provided to the unit.
NIGHT PURGE MODE (STATE NUMBER 8)
Night Purge mode is provided as a means to more easily and quickly
ventilate a space. Night purge can be useful in helping to remove odor
buildupattheend ofeachday,oraftercleaning,painting,orotherodor
generating operations occur within the space. Night Purge is a full
ventilation with exhaust mode, during which room comfort will very
likely be compromised, it is therefore strongly recommended that
Night Purge only be used when the space is unoccupied. The LUI or a
networkconnectioncanforcetheunitintotheNightPurgemode.Night
Purge mode consists of a single UVC state: Night Purge [8].
Transition (UVC Mode = Night Purge)
into State
Operation When Night Purge mode becomes active, the UVC
within State stops all normal heating and cooling as any new energy
used to treat the incoming air would be wasted in the
Figure 8. Night Purge State Diagram

OM 750 Page 11 of 32
FAN ONLY MODE (STATE NUMBER A)
The Fan Only mode is provided so that the UVC can be forced into a
FanOnlyoperation.TheLUIoranetworkconnectioncanforcetheunit
intotheFanOnlymode.FanOnlymodeconsistsofasingleUVCstate:
Fan Only [A].
Transition (UVC Mode = Fan Only)
into State
Operation When Fan Only mode becomes active, the UVC stops
within State all normal heating and cooling. If the space temperature
drops below the EHS, and the Emergency Heat function
is enabled, the UVC will be forced into the Emergency
Heat mode (see the Emergency Heat Mode).
he UVC will remain in this state until one of the
transition out conditions become true.
Transition (UVC Mode ≠ Fan Only)
out of State
Figure 9. Fan Only State Diagram
EMERGENCY HEAT MODE (SUPER STATE)
The Emergency Heat mode is provided for situations where the UVC
is in a mode that does not normally allow heating, such as Off, Cool,
Night Purge, or Fan Only. If Emergency Heat mode is enabled, the
UVC can automatically force itself into the Emergency Heat mode
fromOff,Cool,NightPurge,FanOnly,Purge,Pressurize,De-pressurize,
and Shutdown. Additionally, the LUI or a network connection can be
usedto force theunit into theEmergency Heat mode.Emergency Heat
mode consists of two UVC states: Full Heat [7] and Cant Heat [D].
Transition
into (UVC Mode = Emergency Heat)
Super State
Operation When the Emergency Heat mode super state becomes
within active, the UVC will automatically determine which
Super State which UVC state to make active, Full Heat [7] or Cant
Heat [D], based upon the transitions for each of those
states.
he UVC will remain in this super state until one of the
transition out conditions become true.
Transition
out of (UVC Mode ≠ Emergency Heat)
Super State
Figure 10. Emergency Heat State Diagram
Full Heat State (State Number 7)
TheFullHeatstateisthe“normal”statethattheUVCwillgointowhen
Emergency Heat mode is active.
Transition Heat = Available
into State
Operation When Emergency Heat mode becomes active, the
within State UVC will go into 100% heating until the space
temperature raises to the EHS plus a fixed differential
(9OF / 5OC). In the Emergency Heat mode the space fan
will be set to high speed, and the OA damper will
operate normally. If the UVC forces itself into the
Emergency Heat mode from another mode, then the
UVC will return to the appropriate unit mode once the
space temperature rises to the EHS plus the fixed
differential. he UVC will monitor the DA to ensure
it does not exceed DAHL. If the DA does exceed
DAHL (140OF / 60OC default), then heating will be set
to 0% for a minimum of 2-minutes (fixed) and until the
DA drops 18OF (10OC) fixed differential below
DAHL.
he UVC will remain in this state until one of the
transition out conditions become true, or until one of
the superstate transition out conditions becomes true.
Transition (Heat ≠ Available)
out of State
Notes:
(Heat ≠ Available) is true when an IAT or DAT sensor fault exists (see
Unit Faults).
purging process. In the Night Purge mode the space
fan will be set to high speed, the OA damper will be set
to 100% open, and the Exhaust Fan binary output (see
External Binary Outputs) will be set to On. If not set to
another mode within 1-hour, the UVC will force itself
into the Fan Only mode (see Fan Only Mode). If the
space temperature drops below the EHS, and the
Emergency Heat function is enabled, the UVC will be
forced into the Emergency Heat mode (see Emergency
Heat Mode).
he UVC will remain in this state until one of the
transition out conditions become true.
Transition (UVC Mode ≠ Night Purge)
out of State

Page 12 of 32 OM 750
AUTO MODE
Auto mode is provided so that the UVC can be set to automatically
determine if heating, cooling or dehumidification is required. Auto
mode is the default start-up UVC mode. Auto mode is made up of the
Heat, Cool and Active Dehum (optional, software model 4) modes.
When the UVC is set to auto mode, the UVC will determine which
mode (Heat, Cool or Active Dehum) to use.
Cant Heat State (state number D)
The Cant Heat state is a “non-normal” state that the UVC can go into
when Emergency Heat mode is active. Only an IAT or DAT sensor
fault during Emergency Heat mode will cause the UVC to make this
state active.
Transition (Heat ≠ Available)
into State
Operation When the Cant Heat state becomes active, the space
within State fan will remain at high speed.
he UVC will remain in this state until one of the
transition out conditions become true, or until one of
the super state transition out conditions becomes true.
Transition (Heat = Available)
out of State
Notes:
(Heat ≠ Available) is true when an IAT or DAT sensor fault exists (see
Unit Faults).
HEAT MODE (SUPER STATE)
When in Heat mode the UVC will use primary heat (electric heat) as
neededtomaintaintheeffectiveheatingsetpoint(seeSpaceTemperature
Setpoints). The LUI or a network connection can be used to force the
unitintotheHeat mode. Additionally,theUVCwhenset toAutomode
can automatically force the unit into the Heat mode as needed. When
the UVC is in Auto mode, it is “normal” for the UVC to “idle” in Heat
modewhen there isno need toswitch toanother mode. TheHeat mode
super state consists of three UVC states: Heat [5], Low Limit [E] and
Cant Heat [B].
Transition (UVC Mode = Heat)
into OR
Super State (UVC Mode = Auto AND Space emperature ≠ Warm)
Operation When the Heat mode super state becomes active, the
within UVC will automatically determine which UVC state
Super State to make active, Heat [5], Low Limit [E], or Cant Heat
[B] based upon the transitions for each of those states.
he UVC will remain in this super state until one of the
transition out conditions become true.
Transition (UVC Mode ≠ Heat AND UVC Mode ≠ Auto)
out of OR
Super State (UVC Mode = Auto AND Space emp = Warm AND
Heat PI = Saturated Low)
Figure 11. Heat Mode Super State Diagram

OM 750 Page 13 of 32
Figure 12. Heat State Operation (Occupied Mode and Auto Fan)
Low Limit State (state number E)
The Low Limit state is a “non-normal” state that the UVC can go into
whileHeatmode isactivewhenthe unitreaches100% heating andstill
cannotmeetthecurrentDATS(seeDischargeAirTemperatureControl)
required to maintain the effective heating setpoint (see Space
TemperatureSetpoints).ThisisonlylikelytooccuriftheOAtemperature
is very cold, the OA damper minimum position is set too high, the unit
ventilator is oversized for the application, or if the electric heat has
failed.
Transition (Heat PI = Saturated High AND Heat imer = Expired)
into State OR
(Heat = Available AND Low Limit = Active)
Operation When the Low Limit state becomes active, the Low
within State Limit PI-loop will override the OA damper minimum
position (see Outdoor Air Damper Operation) and
adjust the OA damper toward closed as necessary to
maintain the current DA S (see Discharge Air
emperature Control). he Low Limit imer (10-
minutes fixed) will begin counting.
he UVC will remain in this state until one of the
transition out conditions become true, or until one of
the super state transition out conditions becomes true.
Transition (OAD ≠ Alarm AND Low Limit imer = Expired)
out of State OR
(Heat ≠ Available)
Notes:
The OA damper is considered to be in “alarm” when the OA damper is
forced below the active minimum position in the Low Limit state. This is
not an actual unit “alarm” or “fault” condition, but only a condition used
for the purpose of transition arguments.
Cant Heat State (state number B)
The Cant Heat state is a “non-normal” state that the UVC can go into
whenHeatmodeisactive. AnIATorDATsensorfault during theHeat
mode will cause the UVC to make the Cant Heat state active.
Transition (Heat ≠ Available)
into State
Operation When the Cant Heat state becomes active, no heating
within State or ventilation will take place. he OA damper will be
closed.
he UVC will remain in this state until one of the
transition out conditions become true, or until one of
the super state transition out conditions becomes true.
Transition (Heat = Available AND Low Limit = Active)
out of State OR
(Heat = Available AND Low Limit = Inactive)
Heat State (state number 5)
The Heat state is the “normal” state that the UVC will go into when
Heat mode is active.
Transition (Heat = Available AND Low Limit = Inactive)
into State OR
(OAD ≠ Alarm AND Low Limit imer = Expired)
Operation When the Heat state becomes active, the UVC will
within State continually calculate
the DA S (see Discharge Air
emperature Control) required to maintain the effective
heat setpoint (see Space emperature Setpoints). he
calculated DA S will not be allowed to go above
DAHL. he UVC will use primary heat (electric heat)
as needed to maintain the current DA S. he Heat
imer (3-minutes fixed) will begin counting. he CO2
demand controlled ventilation function will be active,
if the unit is equipped for CO2 control (see CO2 Demand
Controlled Ventilation), and the OA damper will be
adjusted as needed to maintain the CO2 setpoint.
he UVC will remain in this state until one of the
transition out conditions become true, or until one of
the super state transition out conditions becomes true.
Transition (Heat ≠ Available)
out of State OR
(Heat PI = Saturated High AND Heat imer = Expired)
Notes:
The OAD is considered to be in “alarm” when the OAD is forced below
the active minimum position in the Low Limit state. This is not an actual
unit“alarm” or“fault” condition,but onlya conditionusedforthepurpose
of transition arguments.

Page 14 of 32 OM 750
Transition (UVC Mode = Cool)
into OR
Super State (UVC Mode = Auto AND Space emperature = Warm)
Operation When the Cool mode super state becomes active, the
within UVC will automatically determine which UVC state
Super State to
make active, Econ [3], Econ Mech [1], Mech [2],
DA Heat [4], Low Limit [15], Cant Cool [12], or
ActiveDehum [6] based upon the transitions for each
of those states. If the space temperature drops below
EHS, and the Emergency Heat function is enabled, the
UVC will be forced into the Emergency Heat mode
(see Emergency Heat Mode).
he UVC will remain in this super state until one of
the transition out conditions become true.
Transition (UVC Mode ≠ Cool AND UVC Mode ≠ Auto)
of out OR
Super State (UVC Mode = Auto AND Space emp = Cold AND
Mech PI = Saturated Low AND Econ PI = Saturated
Low)
Figure 13. Cool Mode Super State Diagram
COOL MODE (SUPER STATE)
When in Cool mode the UVC will use primary cooling (economizer)
and secondary cooling (mechanical, DX) as needed to maintain the
effectivecoolingsetpoint(seeSpaceTemperatureSetpoints).TheLUI
or a network connection can be used to force the unit into the Cool
mode.Additionally,theUVCwhensettoAutomodecanautomatically
force the unit into the Cool mode. When the UVC is in Auto mode, it
is “normal” for the UVC to “idle” in Cool mode when there is no need
toswitchtoanothermode.TheCoolmodesuper stateconsists ofseven
UVC states: Econ [3], Econ Mech [1], Mech [2], DA Heat [4], Low
Limit [F], Cant Cool [C], and Active Dehum [6] (optional).
“For Reheat
type units”

OM 750 Page 15 of 32
Econ State (state number 3)
The Econ state is a “normal” state that the UVC can go into when Cool
mode is active. The Econ state is typically active in the Cool mode
when primary cooling (economizer) is available and adequate to meet
the cooling requirements.
Transition (Econ = Available AND Mech Cooling
≠ Available)
into State OR
(Space ≠ High CO2 AND Heat PI = Saturated Low
AND DA > VCLL)
OR
((Mech PI = Saturated Low AND Econ Mech imer =
Expired) OR (Mech Cooling ≠ Available))
Operation When the Econ state becomes active, the UVC will
within State use economizer cooling (see Economizer Operation)
as needed to maintain the effective cooling setpoint
(see Space emperature Setpoints). he Econ imer
(3-minutes fixed) will begin counting. he UVC will
monitor the DA to ensure it does not fall below VCLL
(see Ventilation Cooling Low Limit) setpoint. he
CO2 demand controlled ventilation function will be
active, if the unit is equipped for CO2 control (see CO2
Demand Controlled Ventilation), and the OA damper
will be adjusted as needed to maintain the CO2 setpoint.
he UVC will remain in this state until one of the
transition out conditions become true, or until one of
the super state transition out conditions becomes true.
Transition (Econ ≠ Available AND Mech Cooling ≠ Available)
out of State OR
(Space = High CO2 OR DA < VCLL)
OR
(Econ imer = Expired AND Econ PI = Saturated High
AND MechCool = Available)
OR
(Econ ≠ Available AND Mech Cooling = Available)
Figure 14. Econ State Operation (Occupied Mode and Auto Fan)
Figure 15. Econ Mech State Operation (Occupied Mode
and Auto Fan)
Econ Mech State (state number 1)
TheEconMechstateisa“normal” statethattheUVCcangointowhen
Coolmodeisactive.TheEconMechstateistypicallyactiveintheCool
mode when primary cooling (economizer) alone is not adequate to
meetthecoolingrequirementsandbothprimarycoolingandsecondary
cooling (compressor) are available.
Transition (Econ imer = Expired AND Econ PI = Saturated
into State High
AND Mech Cooling = Available)
OR
(Econ = Available)
Operation When the Econ Mech state becomes active, the OA
within State damper will be set to 100% open, and the UVC will use
the unit’s mechanical cooling capabilities (see
Compressor Operation) as needed to maintain the
effective cooling setpoint (see Space emperature
Setpoints). he Econ Mech imer (3-minutes fixed)
will begin counting. he UVC will monitor the DA
to ensure it does not fall below MCLL (see Mechanical
Cooling Low Limit) setpoint.
he UVC will remain in this state until one of the
transition out conditions become true, or until one of
the super state transition out conditions becomes true.
Transition ((Mech PI = Saturated Low AND Econ Mech imer =
out of State Expired) OR (Mech Cooling ≠ Available))
OR
(Econ ≠ Available)

Page 16 of 32 OM 750
Cant Cool State (state number C)
The Cant Cool state is a “non-normal” state that the UVC can go into
when Cool mode is active. The Cant Cool state typically becomes
activewhenprimary(economizer)andsecondary(compressor)cooling
are not available (or they are disabled), an IAT, DAT or OAT sensor
failureduring the Coolmode can alsocause the UVCto make theCant
Cool state active.
Transition (Econ ≠ Available AND Mech Cooling ≠ Available)
into State OR
(Mech Cooling ≠ Available)
Operation When the Cant Cool state becomes active, no cooling
within State will take place.
he UVC will remain in this state until one of the
transition out conditions become true, or until one of
the super state transition out conditions becomes true.
Transition (Econ = Available AND Mech Cooling ≠ Available)
out of State OR
(Econ ≠ Available AND Mech Cooling = Available)
Figure 16. Mech State Operation (Occupied Mode and Auto Fan)
Transition (Econ ≠ Available)
into State OR
(Econ ≠ Available AND Mech Cooling = Available)
Operation When the Mech state becomes active, the UVC will
within State use the unit’s mechanical cooling capabilities (see
Compressor Operation) as needed to maintain the
effective cooling setpoint (see Space emperature
Setpoints). he UVC will monitor the DA to ensure
it does not fall below MCLL (see Mechanical Cooling
Low Limit) setpoint. he CO2 demand controlled
ventilation function will be active, if the unit is equipped
for CO2 control (see CO2 Demand Controlled
Ventilation), and the OAD will be adjusted as needed
to maintain the CO2 setpoint.
he UVC will remain in this state until one of the
transition out conditions become true, or until one of
the super state transition out conditions becomes true.
Transition (Econ = Available)
out of State OR
(Mech Cooling ≠ Available)
Mech State (state number 2)
TheMechstateisa“normal”statethat the UVCcan gointowhenCool
mode is active. The Mech state is typically active in the Cool mode
when primary cooling (economizer) is not available and secondary
cooling (compressor) is available.
DA Heat State (state number 4)
The DA Heat state is a “normal” state that the UVC can go into when
Coolmode isactive. TheDAHeat stateis typicallyactive whenreheat
is required to maintain DATS while maintaining the required OA
damper position. The DA Heat state can also be active if the optional
CO2DCVfeatureisprovidedandCO2levelsarehigh,requiringtheOA
damper to open beyond what would be required for economizer
cooling.
Transition (Space = High CO2 OR DA < VCLL)
into State OR
(Low Limit imer = Expired AND OAD ≠ Alarm)
Operation When DA Heat state is active, then the UVC will use
within State the unit’s heating capability as needed to maintain the
VCLL setpoint. he Heat imer (3-minutes fixed)
will begin counting. he CO2 demand controlled
ventilation function will be active, if the unit is equipped
for CO2 control (see CO2 Demand Controlled
Ventilation), and the OAD will be adjusted as needed
to maintain the CO2 setpoint.
he UVC will remain in this state until one of the
transition out conditions become true, or until one of
the super state transition out conditions becomes true.
Transition (Space ≠ High CO2 AND Heat PI = Saturated Low
out of State AND DA > VCLL)
OR
(Heat PI = Saturated High AND Heat imer = Expired)
Notes:
The OAD is considered to be in “alarm” when the OAD is forced below
the active minimum position in the Low Limit state. This is not an actual
unit“alarm”or“fault”condition,butonlyaconditionusedforthepurpose
of transition arguments.
Low Limit State (state number F)
The Low Limit state is a “non-normal” state that the UVC can go into
while Cool mode is active. The Low Limit state typically follows the
DA Heat state when the UVC has reached 100% heat and still cannot
maintain VCLL.
Transition (Heat PI = Saturated High AND Heat imer = Expired)
into State OR
(Heat = Available AND Low Limit = Active)
Operation When the Low Limit state becomes active, the Low
within State Limit PI-loop will override the OAD minimum position
(see Outdoor Air Damper Operation) and adjust the
OAD toward closed as necessary to maintain the DA
setpoint (see Discharge Air emperature Setpoint).
he Low Limit imer (10-minutes fixed) will begin
counting.

OM 750 Page 17 of 32
Table 8. Actions during Special Purpose Unit Modes
Indoor Air Outdoor Air Exhaust Fan Output
Fan (IAF) Damper (OAD)
Pressurize High 100% Open Off
Depressurize Off Closed On
Purge High 100% Open On
Shutdown Off Closed Off
Energy Hold Off Off Closed Off
Pressurize Mode
WheninPressurizemodethe UVCwillusetheIAF,OAD,andexhaust
output as needed to pressurize the space. The UVC stops all normal
heating and cooling but does allow emergency heat if required. The
pressurize mode can only be accessed via a network connection.
Depressurize Mode
When in Depressurize mode the UVC will use the IAF, OAD, and
exhaust output as needed to depressurize the space. The UVC stops all
normalheating andcooling butdoes allowemergency heatif required.
Thede-pressurizemodecanonlybeaccessedviaanetworkconnection.
Purge Mode
When in Purge mode the UVC will use the IAF, OAD, and exhaust
outputas neededto purgethe space.The UVCstops all normalheating
andcoolingbutdoesallowemergencyheatifrequired.Thepurgemode
can only be accessed via a network connection.
Shutdown Mode
Shutdown mode is the equivalent of the Off mode, but is an Off mode
forced by a network connection. When in Shutdown mode the UVC
stops all normal heating, cooling, ventilation (OA damper is closed),
and fan operation. By default emergency heat will not be used during
theshutdownmode,however,theUVCcanbeconfigured(Emergency
Heat Shutdown Configuration) to allow emergency heat operation
during shutdown mode. The shutdown mode can be accessed via a
network connection and a binary input to the UVC.
Energy Hold Off Mode
The UVC supports an energy hold off state, which when active forces
the UVC to stop all normal heating, cooling and ventilation. Typically
used by a network connection to force the UVC to cease heating,
cooling and ventilation when conditions exist where heating, cooling
and ventilation are not required or desired. Energy hold off mode is
very similar to shutdown mode except that energy hold off always
allows emergency heat if required. The energy hold off mode can only
be accessed via a network connection.
UVC UNIT MODE PRIORITY
The UVC uses the network variables and binary inputs listed in the
following tables, to determine unit mode. Special purpose UVC unit
modes have higher priority than the normal UVC unit modes as shown
inthefollowing tables. Eachtableliststhe highestpriorityitemson the
left to the lower priority items to the right. The right most columns
indicate unit operation as a result of the left most columns.
he UVC will remain in this state until one of the
transition out conditions become true, or until one of
the super state transition out conditions becomes true.
Transition (OAD ≠ Alarm AND Low Limit imer = Expired)
out of State OR
(Heat ≠ Available)
Notes:
The OAD is considered to be in “alarm” when the OAD is forced below
the active minimum position in the Low Limit state. This is not an actual
unit“alarm”or“fault”condition,butonlyaconditionusedforthepurpose
of transition arguments.
Active Dehumidify State (optional with reheat type units)
The Active Dehum state is a “normal” state that the UVC can go into
when Cool mode is active and when the unit is equipped for optional
active dehumidification (see Active Dehumidification).
Transition (Space = High %RH AND Mech Cooling = Available
into State
AND %RH Sensor = Reliable)
Operation When the Active Dehum state becomes active, the
within State UVC will capture the current IA and use this as the
temporary setpoint during dehumidification. he unit’s
mechanical cooling capabilities will initially be set to
100% (compressor on) and the heat PI will maintain
the captured setpoint. If the heat PI saturates high
(100% heat) for 2-minutes or more (i.e. heating cannot
keep up with cooling), the compressor will be disabled
until the compressor’s minimum-off time expires and
the heat PI saturates low (0% heat). he UVC uses a
5%RH fixed differential below the RHS to determine
when active dehumidification is complete. he UVC
will monitor the DA to ensure it does not fall below
MCLL, nor goes above DAHL. he CO2 demand
controlled ventilation function will be active, if the
unit is equipped for CO2 control (see CO2 Demand
Controlled Ventilation), and the OAD will be adjusted
as needed to maintain the CO2 setpoint.
he UVC will remain in this state until one of the
transition out conditions become true, or until one of
the super state transition out conditions becomes true.
Transition Space ≠ High %RH
out of State OR
Mech Cooling ≠ Available
OR
%RH Sensor ≠ Reliable
SPECIAL PURPOSE UNIT MODES
There are some additional UVC modes that are considered special
purpose unit modes, these include Pressurize, Depressurize, Purge,
Shutdown and Energy Hold Off. These modes force the UVC to
perform very specific and limited functions and must be used with
caution and only for short periods as needed. These modes can only be
accessed via a network connection.
In each of these special purpose UVC modes, if the space temperature
drops below EHS, and the Emergency Heat function is enabled, the
UVC will be forced into the Emergency Heat mode (see Emergency
Heat Mode) and then return once the Emergency Heat function is
satisfied.
WARNING
!
Shutdown mode and energy hold off mode is a “stop” state for
theunit ventilator. Itis not a“power off”state.Power maystillbe
provided to the unit.

Page 18 of 32 OM 750
Priority Result
Application Override Input 햳Unit Mode Override Input 햳Unit Mode Output 햳
Heat
Normal (Auto) 햲Cool
Emergency Heat
Heat Heat
Normal (Auto) 햲Cool Cool
Night Purge Night Purge
Off Off
Emergency Heat Emergency Heat
Fan Only Fan Only
Heat Don’t Care Heat
Cool Don’t Care Cool
Night Purge Don’t Care Night Purge
Off Don’t Care Off
Emergency Heat Don’t Care Emergency Heat
Fan Only Don’t Care Fan Only
햲Normal (Auto) is the normal UVC power-up state.
햳These are network variables.
Table 10. Normal UVC Mode Priority
Occupancy Modes
TheUVCisprovidedwith fouroccupancymodes:Occupied,Standby,
Unoccupied, and Bypass. The occupancy mode effects which heating
and cooling temperature setpoints will be used, effects IAF operation,
and effects OAD operation. The Manual Adjust Occupancy and
Priority Result
Occupancy Occupancy Unoccupied Effective
Override Input 햴Sensor Input 햴Input Signal Occupancy
Output 햴
Occupied Don’t Care Don’t Care Occupied
Unoccupied Don’t Care Don’t Care Unoccupied
Occupied Don’t Care Occupied
Unoccupied Don’t Care Bypass
Bypass Contacts Open (Occupied) Occupied
Null (default) Contacts Closed (Unoccupied) Bypass
Standby Don’t Care Don’t Care Standby
Occupied Don’t Care Occupied
Unoccupied Don’t Care Unoccupied 햲
Null (default) 햳Contacts Open (Occupied) Occupied
Null (default) Contacts Closed (Unoccupied) Unoccupied 햲
Table 11. Occupancy Mode Priority
Networked Occupancy Sensor network variables, along with the
Unoccupied and Tenant Override binary inputs, are used to determine
the Effective Occupancy.
Priority Result
Emergency Override Remote Shutdown Energy Hold Energy Hold Unit Mode Actual UVC
Input 햵Binary Input Off Input 햵Off Output 햵Output 햵Action
Normal Normal See the Normal
Normal De-energized UVC Mode Priority table
Energy Hold Off Energy Hold Off Off Off
Energized Don’t Care Energy Hold Off Off Off
Pressurize Don’t Care Don’t Care Don’t Care Off Pressurize
De-pressurize Don’t Care Don’t Care Don’t Care Off De-pressurize
Purge Don’t Care Don’t Care Don’t Care Off Purge
Shutdown Don’t Care Don’t Care Don’t Care Off Off
햲Normal here indicated the UVC power-up condition.
햳De-energized here means that the contacts connected to this binary input are open.
햴Energized here means that the contacts connected to this binary input are closed.
햵These are network variables.
Table 9. Special Purpose UVC Unit Mode Priority
햲The tenant override switch (unit or wall sensor mounted) can be used here to force the UVC into the Bypass Mode.
햳Typical operation is defined in this row of the table.
햴These are network variables.

OM 750 Page 19 of 32
OCCUPIED MODE
The occupied mode is the normal day time mode of UVC operation.
During occupied mode the UVC will use the occupied heating and
cooling setpoints, the OAD will operate normally, and by default the
IAF will remain on.
UNOCCUPIED MODE
The unoccupied occupancy mode is the normal night time mode of
UVC operation. During unoccupied mode the UVC will use the
unoccupiedheatingandcoolingsetpoints,theOADwillremainclosed,
and the IAF will cycle as needed for heating or cooling. The IAF will
remain off when there is no need for heating or cooling.
STANDBY MODE
The standby mode is a special purpose day time mode of UVC
operation. During standby mode the UVC will use the standby heating
and cooling setpoints, the OAD will remain closed, and by default the
IAF will remain on.
BYPASS MODE
The bypass mode (also called Tenant Override) is the equivalent of a
temporary occupied mode. Once the bypass mode is initiated it will
remain in effect for a set period of time (120-minutes default). During
the bypass mode the UVC will use the occupied heating and cooling
setpoints, the OAD will operate normally, and by default the IAF will
remain on.
NETWORKED OCCUPANCY SENSOR CAPABILITY
A networked occupancy sensor can be interfaced with the Occupancy
SensorInputvariabletoselectoccupancymodes.WhentheOccupancy
Sensor Input variable is used, it will automatically override any hard-
wired unoccupied binary input signal.
UNIT-MOUNTED TIME-CLOCK
An optional unit-mounted factory-installed electronic 24-hour/7-day
timeclockcanbeprovidedonsomeunitventilatorconfigurations.This
timeclockisfactorywiredtotheUVCunoccupiedbinaryinputandcan
be set to automatically place the unit into occupied and unoccupied
modes based upon its user configured schedule.
UNIT-MOUNTED TENANT OVERRIDE SWITCH
A tenant override switch is factory installed in all floor mounted units.
This tenant override switch is located near the LUI on the unit. The
tenant override switch provides a momentary contact closure that can
be used by room occupants to temporarily force the UVC into the
bypass occupancy mode from unoccupied mode.
REMOTE WALL-MOUNTED SENSOR TENANT
OVERRIDE SWITCH
The optional remote wall-mounted sensors include a tenant override
switch. This tenant override switch provides a momentary contact
closure that can be used by room occupants to temporarily force the
UVC into the bypass occupancy mode from unoccupied mode.
REMOTE WALL-MOUNTED SENSOR STATUS LED
The optional remote wall-mounted sensors each include a UVC status
LED. This status LED aids is diagnostics by indicating the UVC
occupancy mode and fault condition.
Indication LED Operation
Occupied On Continually
Unoccupied On 1-sec / Off 9-sec
Bypass On Continually
Standby On 9-sec / Off 1-sec
Fault On 5-sec / Off 5-sec
Table 12. Remote Wall-Mount Sensor Status LED
Space Temperature Setpoints
The UVC uses the six occupancy-based temperature setpoints as the
basis to determine the Effective Setpoint Output. The UVC will
calculatetheeffectivesetpointbasedupontheunitmode,theoccupancy
mode, and the values of several network variables. The effective
setpoint is then used as the temperature setpoint that the UVC will
maintain.
Temperature Setpoints Abr. Defaults
Unoccupied Cool UCS 82.4OF (28.0OC)
Standby Cool SCS 77.0OF (25.0OC)
Occupied Cool OCS 73.4OF (23.0OC)
Occupied Heat OHS 69.8OF (21.0OC)
Standby Heat SHS 66.2OF (19.0OC)
Unoccupied Heat UHS 60.8OF (16.0OC)
Table 13. Default Occupancy-based Temp Setpoints
NETWORKED SETPOINT CAPABILITY
TheSpaceTempSetpointInputvariableisusedtoallowthetemperature
setpoints for the occupied and standby modes to be changed via the
network, the unoccupied setpoints are not effected by this variable.
NETWORKED SETPOINT OFFSET CAPABILITY
The Setpoint Offset Input variable is used to shift the effective
occupied and standby temperature setpoints by adding the value of the
Setpoint Offset Input variable to the current setpoints, the unoccupied
setpoints are not effected by this variable. This variable is typically
boundtoasupervisorynetworkcontroller(byothers)ortoanetworked
wall module (by others) having a relative setpoint adjustment.
NETWORKED SETPOINT SHIFT CAPABILITY
TheSetpoint ShiftInput variableisused toshift theeffective heat/cool
setpoints. It is typically bound to a networked supervisory controller
whichprovidesfunctionssuchasoutdoorairtemperaturecompensation.
Alloccupied,standbyandunoccupiedsetpoints willbeshiftedupward
(+) or downward (-) by the corresponding value of the Setpoint Shift
Input variable.
The Setpoint Shift Input capability is not available through the
BACnet® interface.
NETWORKED SPACE TEMPERATURE
SENSOR CAPABILITY
A networked space temperature sensor can be interfaced with the
Space Temp Input variable. When the Space Temp Input variable is
used (valid value), it will automatically override the hard-wired space
temperature sensor.
NOTICE

Page 20 of 32 OM 750
NOTICE
NOTICE
IfitisintendedthattheLUIwillbeusedbyroomoccupantstoadjust
theSetpointOffset,thenyoumustnotusetheoptionalremotewall-
mounted sensor with 55OF to 85OF adjustment. When using the
optionalremotewall-mountedsensorwith55OFto85OFadjustment,
the UVC will ignore any Setpoint Offset changes made at the LUI.
NOTICE
Given
OccupancyMode = Occupied or Bypass
Heat/CoolMode = Heat
SpaceTempSetpoint = (not used)
SetpointOffset = (not used) = 0.0OF
SetpointShift = (not used) = 0.0OF
OHS = 69.8°F
Effective Setpoint Calculations
EffectiveSetpoint = OHS + SetpointOffset + SetpointShift
= 69.8 + 0.0 + 0.0 = 69.8OF
Given
OccupancyMode = Occupied or Bypass
Heat/CoolMode = Heat
SpaceTempSetpoint = 71.0OF
SetpointOffset = -1.0OF (occupant adjustment on remote wall
sensor, or LUI)
SetpointShift = (not used) = 0.0OF
OCS = 73.4°F, OHS = 69.8°F
Effective Setpoint Calculations
AbsoluteOffset = (OCS– OHS) / 2 =(73.4OF – 69.8OF)/ 2=1.8OF
EffectiveSetpoint = SpaceTempSetpoint – AbsoluteOffset
+ SetpointOffset + SetpointShift = 71.0 - 1.0 - 1.0 + 0.0 = 68.2OF
Given
OccupancyMode = Occupied or Bypass
Heat/CoolMode = Cool
SpaceTempSetpoint = 71.0OF
SetpointOffset = (not used) = 0.0OF
SetpointShift = (not used) = 0.0OF
OCS = 73.4°F, OHS = 69.8°F
Effective Setpoint Calculations
AbsoluteOffset = (OCS – OHS) / 2 = (73.4 – 69.8) / 2 = 1.8OF
EffectiveSetpoint = SpaceTempSetpoint + AbsoluteOffset +
SetpointOffset + SetpointShift = 71.0 + 1.8 + 0.0 + 0.0 = 72.8OF
Given
OccupancyMode = Unoccupied
Heat/CoolMode = Heat
SpaceTempSetpoint = 71.0OF
SetpointOffset = -1.0OF (occupant adjustment on remote wall
sensor, or LUI)
SetpointShift = (not used) = 0.0OF
UHS = 60.8°F
Effective Setpoint Calculations
EffectiveSetpoint = UHS + SetpointShift = 60.8 + 0.0 = 60.8OF
See table 13 for default values.
Note OHS, OCS can be different than default values.
Table 14. Effective Temp Setpoint Calculation Examples
NOTICE
NOTICE
LUI SETPOINT OFFSET ADJUSTMENT
The LUI can be used to make adjustments to the value of the Setpoint
Offset Input variable. See “Using the LUI to adjust Setpoint Offset”.
The LUI and the network can both effect the Setpoint Offset Input
variable,keepinmindthatchangesto thisvariablewillbelast-one-
wins.
REMOTE WALL-MOUNTED SENSOR WITH +/- 3OF
ADJUSTMENT (OPTIONAL)
Whentheoptionalremotewall-mountedsensorwith+/-3OFadjustment
dial is used, the UVC will effectively write the value of the setpoint
adjustment dial to the Setpoint Offset Input variable.
If it is intended that a network connection will be used to adjust the
Setpoint Offset Input variable, then you must not use the optional
remote wall-mounted sensor with +/- 3OF adjustment.
IfitisintendedthattheLUIwillbeusedbyroomoccupantstoadjust
theSetpointOffset,then youmustnotusethe optionalremotewall-
mounted sensor with +/- 3
O
F adjustment. If you have the optional
remotewall-mountedsensorwith+/-3
O
Fadjustmentandanoccupant
usestheLUItomake SetpointOffsetadjustments, thiswilloverride
any+/-3
O
Fadjustmentontheoptionalremotewall-mountedsensor
asthe LUI has higherpriority. If youfindthat changes tothe +/- 3
O
F
adjustment on the remote wall-mounted sensor have no effect, it is
likely the LUI has been used by an occupant to make a Setpoint
Offset change, cycle unit power to clear this situation and restore
theabilitytochangetheSetpointOffsetfromthe+/-3
O
Fadjustment
on the remote wall-mounted sensor.
REMOTE WALL-MOUNTED SENSOR WITH 55OF TO 85OF
ADJUSTMENT (OPTIONAL)
When the optional remote wall-mounted sensor with 55OF to 85OF
adjustment dial is used, the UVC will effectively write the value of the
setpoint dial to the Space Temp Setpoint Input variable.
If it is intended that a network connection will be using the Space
Temp Setpoint Input variable, then you must not use the optional
remote wall-mounted sensor with 55OF to 85OF adjustment.
EFFECTIVE SETPOINT CALCULATION EXAMPLES
The UVC calculates the effective setpoint (Effective Setpoint Output)
based upon the six occupancy setpoints for heating and cooling,
occupancy mode, and the value of the network variables Space Temp
Setpoint Input, Setpoint Offset Input and Setpoint Shift Input. The
UVC will determine if heating or cooling is required based upon the
current unit mode (Heat/Cool Mode Output) and then calculate the
required setpoint for heating or cooling. After this calculation, the
UVC sets the Effective Setpoint Output network variable equal to the
calculated setpoint. The Effective Setpoint Output is the temperature
setpoint that the UVC will maintain and which is normally displayed
on the LUI. The following table provides some examples of how the
UVC temperature setpoints are calculated.
Example D Example C Example B Example A
NOTICE
When using the optional remote wall-mounted sensor with 55OF to
85OF adjustment, the adjustment dial sets the value of the Space
Temp Setpoint Input variable. The LUI will display the Effective
Setpoint Output as shown in the Effective Setpoint Calculation
Examples.