Installation Manual
MicroTech III® Unit Controller for Applied
Rooftop and Self-Contained Systems
RAH, RCS, RDS, RDT, RFS, RPS, SWP, and SWT
© 2008 McQuay International
IM 919
Group: Applied Systems
Part Number: IM 919
Date: October 2008
Contents
Introduction .............................................................. 4
General Description............................................ 5
Component Data ................................................ 5
Control Panel...................................................... 6
Main Control Board (MCB) ................................. 8
Expansion Boards A, B, C .................................. 8
Dip Switch Settings for Expansion Boards ......... 9
Keypad/Display ...................................................... 10
Passwords ........................................................ 10
Navigation Mode .............................................. 12
Edit Mode ......................................................... 12
Description of Operation ....................................... 13
Temperature Sensors....................................... 13
Pressure Sensors ............................................. 17
Duct Pressure Sensor ...................................... 18
Building Pressure Sensor ................................. 18
Actuators .......................................................... 19
Variable Frequency Drives (VFD's)................... 19
Smoke Detectors .............................................. 19
Controller Inputs/Outputs ...................................... 20
Field Wiring ............................................................. 26
Field Output Signals.......................................... 26
Field Analog Input Signals ................................ 28
External Outdoor Air Damper Reset Signal ...... 32
Humidity Sensors.............................................. 32
Field Digital Input Signals ................................. 33
Cooling: Multistage ................................................ 34
Compressor Staging ......................................... 34
Communication Module ......................................... 43
Network Communications ................................. 43
Software Identification and Configuration ........... 44
Typical Electrical Drawings - Rooftop .................. 46
Typical Electrical Drawings - Self Contained....... 56
Parts List ................................................................. 64
Introduction
Introduction
This manual contains information regarding the MicroTech III® control system used in the
McQuay Rooftop and Self Contained product lines. It describes the MicroTech III
components, input/output configurations, field wiring options and requirements, and service
procedures. For a description of operation and information on using the keypad to view data
and set control parameters, refer to the appropriate operation manual. For installation and
commissioning instructions and general information on a particular unit model, refer to its
model-specific installation manual.
Table 1: Operation, Installation and Maintenance Resources
Unit
Manual
MicroTech III Rooftop Unit Controller - BACnet IP
Communications
MicroTech III Rooftop Unit Controller - BACnet
MSTP Communications
MicroTech III Rooftop Unit Controller - BACnet
LON Communications
Rooftop/Self-Contained Operation
RPS/RDT/RFS/RCS 015C-105C
RPS/RDT/RFS/RCS 050D-140D
SWP Self-Contained (018 to 105)
IM 916
IM 917
IM 918
OM 920
IM 926
IM 893
IM 937
NOTICE
This equipment generates, uses, and can radiate radio frequency energy and,
if not installed and used in accordance with this instruction manual, may cause
interference to radio communications. It has been tested and found to comply
with the limits for a Class A digital device, pursuant to part 15 of the FCC rules.
These limits are 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 is required to correct the interference at his
own expense. McQuay International disclaims any liability resulting from
any interference or for the correction thereof.
WARNING
Electric shock hazard. Can cause personal injury or equipment damage.
This equipment must be properly grounded. Connections and service to the
MicroTech III control panel must be performed only by personnel that are
knowledgeable in the operation of the equipment being controlled.
WARNING
Excessive moisture in the control panel can cause hazardous working
conditions and improper equipment operation.
When servicing this equipment during rainy weather, the electrical
components in the main control panel must be protected from the rain.
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Introduction
CAUTION
Extreme temperature hazard. Can cause damage to system components.
The MicroTech III controller is designed to operate in ambient temperatures
from -20°F to 125°F. It can be stored in ambient temperatures from -40°F to
140°F. It is designed to be stored and operated in relative humidity up to 95%
(non-condensing).
CAUTION
Static sensitive components. A static discharge while handling
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.
General Description
The MicroTech III Unit Controller is a microprocessor-based controller designed to provide
sophisticated control of McQuay Air Handling unit. In addition to providing normal
temperature, static pressure, and ventilation control, the controller can provide alarm
monitoring and alarm-specific component shutdown if critical system conditions occur.
The operator can access temperatures, pressures, operating states, alarm messages, control
parameters, and schedules with the keypad/display. The controller includes password
protection against unauthorized or accidental control parameter changes.
This MicroTech III controller is capable of complete, stand-alone rooftop unit control, or it can
be incorporated into a building-wide network using an optional plug-in communication
module. Available communication modules include BACnet/IP, BACnet MS/TP, and
LONMARK.
Component Data
The main components of the MicroTech III control system include the main control board
(MCB) with a built in keypad/display and I/O's, Expansion Modules A, B, C. Transformers
T2, T3 and T9 supply power to the system. The following pages contain descriptions of these
components and their input and output devices.
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Introduction
Control Panel
Figure 1: Control Panel - 208 V, 36 Ton
6
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Introduction
Figure 2: Control Panel - 208 V, 68 Ton with Speedtrol
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Introduction
Main Control Board (MCB)
Figure 3: Main Control Board
Expansion Boards A, B, C
Figure 4: Expansion Board
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Introduction
Figure 5: Expansion Board Side Views
Dip Switch Settings for Expansion Boards
Figure 6: Dip Switch Settings
Expansion Board A = #5 switch in the up position (all others down)
Expansion Board B = #4 switch in the up position (all others down)
Expansion Board C = #4 & #5 switch in the up position (all others down)
Dipswitch #6 must be in the up position on the last Expansion Board in the string regardless
whether it is A, B, or C.
Table 2: MCB I/O Connection Labeling
McQuay IM 919
MCB I/O
Connection Label
T1
T2
T3
T4
T5
T6
T7
T8
T9
T10
T11
T12
T13
24 VOLT POWER SUPPLY
DIGITAL OUTPUT 1,
DIGITAL OUTPUT 2, 3, 4
DIGITAL OUTPUT 5, 6, 7, 8
DIGITAL OUTPUT 9, 10
DIGITAL INPUT 5, 6
ANALOG INPUT 1, 2, 3
UNIVERSAL I/O 1, 2, 3, 4
UNIVERSAL I/O 5, 6, 7, 8
DIGITAL INPUT 1, 2
DIGITAL INPUT 3, 4
MODBUS/VFD
PROCESS BUS/FUTURE
9
Keypad/Display
Keypad/Display
The keypad/display consists of a 5-line by 22 character display, three keys and a “push and
roll” navigation wheel. There is an Alarm Button, Menu (Home) Button, and a Back Button.
The wheel is used to navigate between lines on a screen (page) and to increase and decrease
changeable values when editing. Pushing the wheel acts as an Enter Button.
Figure 7: Keypad/Display
System Summary
3/23
Advanced Menus
Alarm Lists
Unit State=
Clg Capacity=
Cooling
25%
The first line on each page includes the page title and the line number to which the cursor is
currently “pointing”. The line numbers are X/Y to indicate line number X of a total of Y lines
for that page. The left most position of the title line includes an “up” arrow to indicate there
are pages "above" the currently displayed items, a "down" arrow to indicate there are pages
“below” the currently displayed items or an "up/down" arrow to indicate there are pages
“above and below” the currently displayed page.
Each line on a page can contain status only information or include changeable data fields.
When a line contains status only information and the cursor is on that line all but the value
field of that line is highlighted meaning the text is white with a black box around it. When the
line contains a changeable value and the cursor is at that line, the entire line is highlighted.
Each line on a page may also be defined as a “jump” line, meaning pushing the navigation
wheel will cause a “jump” to a new page. An arrow is displayed to the far right of the line to
indicate it is a “jump” line and the entire line is highlighted when the cursor is on that line.
The keypad/display Information is organized into five main menus or menus groups; Alarm
Lists Menu, System Summary Menu, Standard Menus, Extended Menus and Advance Menus.
Note – Only menus and items that are applicable to the specific unit configuration are displayed.
The Alarm Lists Menu includes active alarm and alarm log information. The System
Summary Menu includes status information indicating the current operating condition of the
unit. Standard Menus include basic menus and items required to setup the unit for general
operation. These include such things are control mode, occupancy mode and heating and
cooling setpoints. Extended Menus include more advanced items for “tuning” unit operation
such as PI loop parameters and time delays. Advanced Menus include the most advanced
items such as “unit configuration” parameters and service related parameters. These generally
do not needing changing or accessing unless there is a fundamental change to or a problem
with the unit operation.
Passwords
When the keypad/display is first accessed, the Home Key is pressed, the Back Key is pressed
multiple times, or if the keypad/display has been idle for the Password Timeout timer (default
10 minutes), the display will show a “main” page where the user can enter a password or
continue without entering a password. The three password levels available are Level 2, Level
4, and Level 6, with Level 2 having the highest level of access. Entering the Level 6 password
allows access to the Alarm Lists Menu, System Summary Menu, and the Standard Menus
group. Entering the Level 4 password allows similar access to Level 6 with the addition of the
Extended Menus group. Entering the Level 2 password allows similar access to Level 4 with
the addition of the Advanced Menus group. The Level 2 password is 6363, the Level 4 is
2526, and the Level 6 password is 5321. Continuing without entering one of these three levels
allows access only to the Alarm Lists Menu and the System Summary Menu.
Note – Alarms can be acknowledged without entering a password.
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Keypad/Display
Figure 8: Password Main Page
McQuay AHU
1/3
Enter Password
Continue W/O Password
Version Information
The password field initially has a value **** where each * represents an adjustable field.
These values can be changed by entering the Edit Mode described below.
Figure 9: Password Entry Page
Enter Password 1/1
Enter Password
****
Entering an invalid password has the same effect as continuing without entering a password.
Once a valid password has been entered, the controller allows further changes and access
without requiring the user to enter a password until either the password timer expires or a
different password is entered. The default value for this password timer is 10 minutes. It is
changeable from 3 to 30 minutes via the Timer Settings menu in the Extended Menus.
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Keypad/Display
Navigation Mode
In the Navigation Mode, when a line on a page contains no editable fields all but the value
field of that line is highlighted meaning the text is white with a black box around it. When the
line contains an editable value field the entire line is inverted when the cursor is pointing to
that line.
When the navigation wheel is turned clockwise, the cursor moves to the next line (down) on
the page. When the wheel is turned counter-clockwise the cursor moves to the previous line
(up) on the page. The faster the wheel is turned the faster the cursor moves.
When the Back Button is pressed the display reverts back to the previously displayed page. If
the Back button is repeated pressed the display continues to revert one page back along the
current navigation path until the “main menu” is reached.
When the Menu (Home) Button is pressed the display reverts to the “main page”.
When the Alarm Button is depressed, the Alarm Lists menu is displayed.
Edit Mode
The Editing Mode is entered by pressing the navigation wheel while the cursor is pointing to a
line containing an editable field. Once in the edit mode pressing the wheel again causes the
editable field to be highlighted. Turning the wheel clockwise while the editable field is
highlighted causes the value to be increased. Turning the wheel counter-clockwise while the
editable field is highlighted causes the value to be decreased. The faster the wheel is turned
the faster the value is increased or decreased. Pressing the wheel again cause the new value to
be saved and the keypad/display to leave the edit mode and return to the navigation mode.
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Description of Operation
Description of Operation
Temperature Sensors
The MicroTech III controller uses passive negative temperature coefficient (NTC) 10K ohm
sensors. These sensors vary their input resistance to the MCB as the temperature changes.
Figure 10: Input Resistance
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Description of Operation
Figure 11: Input Resistance (continued)
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Description of Operation
Figure 12: Input Resistance (continued)
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Description of Operation
Figure 13: DAT, RAT, OAT, and EFT Sensor Wiring
Figure 14: MAT and EWT Sensor Wiring
Figure 15: LAT and EAT Sensor Wiring
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Description of Operation
Pressure Sensors
The MicroTech III controller uses 0 to 5" W.C. static pressure transducers for measuring duct
static pressure. As the duct static pressure varies from 0-5" W.C., the transducer output will
vary from 4-20mA. The transducer output signal is 4-20mA however the signal entering the
VFD is converted to a DC signal via a 500 Ohm resistor across the output signal at the
transducer.
If building static pressure control is provided, a -0.25" W.C. to 0.25" W.C. static pressure
transducer is used. As the building static pressure varies from -0.25" W.C. to 0.25" W.C., the
transducer output will vary from 4-20mA. The transducer output signal is 4-20mA however
the signal entering the VFD is converted to a DC signal via a 500 Ohm resistor across the
output signal at the transducer.
Troubleshooting Pressure Transducers
If the duct static pressure always reads 0" WC on the unit keypad/display and the VFD speed
is continuously ramping to 100%, check the following:
If the unit has two duct static pressure sensors (SPS1 and SPS2), verify that they both function
properly per the following procedure. Also check for faulty wiring connections at the VFD
analog inputs.
The controller displays and controls to the lower of the two readings. If a sensor is defective
and inputs 0 volts to the VFD, the static pressure reading on the keypad/display reads 0 and
the controller attempts to increase the 0 value to set point by ramping the VFD up.
If a second sensor (SPS2) is not installed or the pressure tubing to it is not connected, make
sure the 2nd DSP Sensor= parameter in the Unit Configuration menu of the keypad/display is
set to “No” so that the controller ignores the second static pressure analog input.
If a second sensor (SPS2) is installed, make sure the 2nd DSP Sensor= parameter in the Unit
Configuration menu of the keypad/display is set to “Yes”.
Check the 24 VDC power supply to the sensor, verify that there is 24 VDC between the
suspect transducer “+” and “-” terminals.
Using an accurate manometer or gauge, measure the same pressure that the suspect transducer
is sensing. To do this, tap into the transducer high and low pressure tubing or locate the
measurement device taps next to the transducer taps.
If the suspect sensor is measuring duct static pressure, verify that the high and low pressure
taps are properly installed. An improper pressure tap installation can cause severe fluctuations
in the sensed pressure. Refer to the model-specific installation manual for pressure tap
installation guidelines.
Measure the DC voltage output from the transducer across the sensor “S” and “-” terminals.
If the measured voltage and pressure do not match, there may be a wiring problem, the factory
500 ohm resistor across “S” and “-” or the transducer may be defective. Check the transducer
input circuit wiring and connections for defects. If the measured voltage and pressure match,
the VFD parameters and/or ModBus communication between the controller and the VFD will
need to be verified.
Remove powers from the controller by opening system switch S1. If available, swap a similar
good transducer with the suspect transducer or try installing a new transducer. Restore power
by closing S1 and verify whether the suspect transducer is defective.
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Description of Operation
Duct Pressure Sensor
Input Voltage - 24 VDC
Output - 4-20 mA
Note – The transducer output signal is 4-20mA however the signal entering the VFD is converted
to a DC signal via a 500 Ohm resistor across the output signal(“S” and “-”).
Figure 16: Duct Pressure Sensor
Building Pressure Sensor
Input Voltage - 24 VDC
Output - 4-20 mA
Note – The transducer output signal is 4-20mA however the signal entering the VFD is converted
to a DC signal via a 500 Ohm resistor across the output signal(“S” and “-”).
Figure 17: Building Pressure Sensor
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Description of Operation
Actuators
The actuators are controlled by an analog signal from the unit controller. Damper actuators
utilize a 0-10VDC analog signal while modulating heating/cooling valve actuators utilize a 210VDC signal. Spring-return actuators are used for the 0 - 30% outdoor air and economizer
dampers. The mixing dampers are normally closed to the outside air.
Figure 18: Actuator Wiring Diagram
Variable Frequency Drives (VFD's)
When controlling discharge, return or exhaust fan, energy recovery wheel or evaporating
condenser fan variable frequency drives, the MicroTech III controller uses an internal ModBus
communications channel for control and monitoring of the Variable Frequency Drives.
Figure 19: VFD Wiring Diagram
Smoke Detectors
Field installed smoke detectors in the return air ductwork or the supply air ductwork can be
coordinated with the units operation through the main controller's binary input, DI4. This input
is wired to TB2 and the supply air smoke detector can be wired between terminals 103 and
104 and the return air smoke detector can be wired between terminals 104 and 105. The T2
transformer supplies 24 V (ac) across each of these terminals and a dry set of contacts can be
wired to these terminals respectively. This and additional wiring information can be seen on
the input wiring schematics at line number 220.
Figure 20: Smoke Detector Wiring Diagram
Note – Factory smoke detectors are wired the same as field mounted.
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Controller Inputs/Outputs
Controller Inputs/Outputs
Table 3: Controller and Expansion Board I/O
PolyCool 600 Main Controller - RTU
Analog Inputs – 10K NTC
#
AI 1
AI 2
AI 3
Point
Discharge Temperature
Return Temperature
Outdoor Temperature
Comments
10K Thermistor
10K Thermistor
10K Thermistor
Universal Inputs/Outputs
#
X1
X2
X3
X4
X
X
Point
CO2 / Min OA
Low Pressure 1 and
2/Chilled Wtr1
Space Temperature
Zone Setpoint or DAT Reset
X5
X6
X
X
Enthalpy&Freeze Sw2
Ent Fan & Lvg Coil T
X7
X8
DI
AI
X
X
DO
AO
X
X
OA Damper
Comments
0-10VDC or 4-20 mA
1K & 2K Ohm Input/0-10 VDC
10K Thermistor
.5 – 1.5 kOhm or 0-10VDC/420mA
1K & 1.5K Ohm Input
10K Thermistor - Gas or Electric
Heat & Dehum
0-10 VDC
Digital Inputs – Dry Contacts
#
DI 1
DI 2
#
DI 3
DI 4
#
DI 5
DI 6
#
DO 1
DO 2
DO 3
DO 4
DO 5
DO 6
DO 7
DO 8
Point
Comments
Air Flow Switch
Dry Contact
Filter Switch
Dry Contact
Digital Inputs – 24V
Point
Comments
Remote Start / Stop
External 24V
Emergency Off
External 24V
Digital Inputs – 115 V
Point
Comments
High Pressure 1
115 VAC Input
High Pressure 2
115 VAC Input
Digital Outputs – Relay (SPST, Normally Open, 230 VAC 3 Amp
Point
Comments
Compressor 1
Compressor 3
Compressor 2
Compressor 4
Supply Fan
Cond Fan Output A/ Generic Comp 7
Cond Fan Output B/ Generic Comp 8
2 Relays, CF3 & CF4
2 Relays, CF5 & CF6
Digital Outputs – Solid State Relays, 24-230 VAC, .5 A
DO 9
DO 10
Alarm
Fan Operation / VAV Box Output
Note – When used for LP1 and LP2, LP1 is considered Closed when resistance value is 0-799 or
1250-1800. Otherwise LP1 is considered Open. LP2 is considered Closed when the
resistance value is 0-1249, otherwise LP2 is considered Open.
Note – Enthalpy switch is considered Closed when resistance value is 0-799 or 1250-1800.
Otherwise it is considered Open. Freezestat is considered Closed when the resistance
value is 0-1249, otherwise it is considered Open.
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Controller Inputs/Outputs
Table 4: RTU - Expansion Module A
RTU - Expansion Module A
Design Flow, Energy Recovery, Dehumidification, Head Pressure Control, 5 or 6 Compressors
Universal Inputs/Outputs
#
X1
X2
X3
X4
DI
AI
X
X5
X
X6
X7
X8
X
X
X
DO
AO
Point
Comments
X
X
Reheat#1
Reheat#2
Supply Temp Leaving
Wheel/DesignFlo 1
Exhaust Temp Leaving
Wheel/DesignFlo 2
Relative Humidity
High Refrigerant Pressure 1
High Refrigerant Pressure 2
0-10VDC
0-10VDC
10K Thermistor-Energy
Recvy/Ratiometric
10K Thermistor-Energy
Recvy/Ratiometric
0-10 VDC or 4-20 mA
Ratiometric input required
Ratiometric input required
Digital Outputs – Relay (SPST, Normally Open, 230 VAC 3 Amp)
#
DO 1
DO 2
DO 3
DO 4
Point
Compressor 5
Compressor 6
Cond Fan Output C
Constant Speed Enthalpy Wheel
Comments
Energy Recovery
Digital Outputs – Triac (24 VAC, .5 Amp)
#
DO 5
DO 6
Point
Bypass Damper Closed
Bypass Damper Open
Comments
Energy Recovery
Energy Recovery
Note – Expansion Module A dipswitches are always set to address #1. Dipswitch #6 must be in
the on position when it is the last module.
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Controller Inputs/Outputs
Table 5: RTU - Expansion Module B
RTU - Expansion Module B
Staged Heat, F&BP Dampers
Universal Inputs/Outputs
#
X1
X2
X3
X4
X5
X6
X7
X8
DI
X
X
X
AI
DO
AO
Point
Gas Heat Purge Enable (FSG4)
Gas Heat LS1 Switch
Gas heat LS2 Switch
Comments
Dry Contact
Dry Contact
Dry Contact
X
X
Heating Valve
F&BP Damper
2-10 VDC/0-10 VDC
0-10 VDC
Digital Outputs – Relay (SPST, Normally Open, 230 VAC 3 Amp)
#
DO 1
DO 2
DO 3
DO 4
Point
Gas Heat (On/Off)/Heat Stage 1
Gas Heat (On/Off) Heat Stage 2
Heat Stage 3
Heat Stage 4
Comments
Digital Outputs – Triac (24 VAC, .5 Amp)
#
DO 5
DO 6
Point
Heat Stage 5
Heat Stage 6
Comments
Note – Expansion Module B dipswitches are always set to address #2. Dipswitch #6 must be in
the on position when it is the last module.
Table 6: RTU - Expansion Module C
RTU - Expansion Module C
Evaporative Condensing
Universal Inputs/Outputs
#
X1
X2
X3
DI
X4
X5
X6
X7
X8
#
DO 1
DO 2
DO 3
DO 4
#
DO 5
DO 6
X
AI
DO
AO
Point
Comments
X
Sump Temperature
X
Conductivity
10K Thermistor- Evaporative
Condensing
4-20 mA -Evaporative
Condensing
Sump Pump Status
Dry Contact
Digital Outputs – Relay (SPST, Normally Open, 230 VAC 3 Amp)
Point
Comments
Drain Valve
Sump Pump
Digital Outputs – Triac (24 VAC, .5 Amp)
Point
Evaporative Condensing
Evaporative Condensing
Comments
Note – Expansion Module C dipswitches are always set to address #3. Dipswitch #6 must be in
the on position when it is the last module.
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Controller Inputs/Outputs
Table 7: PolyCool 600 Main Controller - SCU
PolyCool 600 Main Controller - SCU
Analog Inputs – 10K NTC
#
AI 1
AI 2
AI 3
#
X1
X2
DI
AI
X
X
X3
X4
X
X
X5
X6
X
X7
X8
DO
Point
Discharge Temperature
Return Temperature
Outdoor Temperature
Universal Inputs/Outputs
AO
Point
Entering WaterTemperature
Low Pressure 1 & 2/Chilled
Wtr1
Space Temperature
Zone Setpoint or DAT Reset
X
X
X
Enthalpy & Freeze Sw2
Bypass/Water Regulating
Valve
Economizer
Mixed Air Temp
Comments
10K Thermistor
10K Thermistor
10K Thermistor
Comments
10K Thermistor
1K & 2K Ohm Input/0-10 VDC
10K Thermistor
.5 – 1.5 kOhm or 0-10VDC/420mA
1K & 2K Ohm Input
0 – 10 VDC
0 – 10 VDC
10K Thermistor
Digital Inputs – Dry Contacts
#
DI 1
DI 2
#
DI 3
DI 4
#
DI 5
DI 6
Point
Air Flow Switch
Filter Switch
Digital Inputs – 24V
Point
Remote Start / Stop
Emergency Off
Digital Inputs – 115V
Point
High Pressure 1
High Pressure 2
Comments
Dry Contact
Dry Contact
Comments
External 24V
External 24V
Comments
115 VAC Input
115 VAC Input
Digital Outputs – Relay (SPST, Normally Open, 230 VAC 3 Amp
#
DO 1
DO 2
DO 3
DO 4
DO 5
DO 6
DO 7
DO 8
DO 9
DO 10
Point
Compressor 1
Compressor 3
Compressor 2
Compressor 4
Supply Fan
Comments
Outdoor Damper Open/Close
Pump On/Off
Digital Outputs – Solid State Relays, 24-230 VAC, .5 A
Alarm
Fan Operation / VAV Box Output
Note – When used for LP1 and LP2, LP1 is considered Closed when resistance value is 0-799 or
1250-1800. Otherwise LP1 is considered Open. LP2 is considered Closed when the
resistance value is 0-1249, otherwise LP2 is considered Open.
Note – Enthalpy switch is considered Closed when resistance value is 0-799 or 1250-1800.
Otherwise it is considered Open. Freezestat is considered Closed when the resistance
value is 0-1249, otherwise it is considered Open.
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Controller Inputs/Outputs
Table 8: SCU - Expansion Module A
SCU - Expansion Module A
All Units: (CO2/Remote Min OA, Waterflow Switch, Dehumidification, Head Pressure Control, 5
or 6 Compressors)
Universal Inputs/Outputs
#
X1
X2
X3
X4
X5
X6
DI
AI
X
DO
AO
Point
CO2 / Min OA
Reheat#1
Reheat#2
Comments
0-10VDC or 4-20 mA
0-10VDC
0-10VDC
X
Waterflow Switch
Relative Humidity
X
X
High Refrigerant Pressure 1
High Refrigerant Pressure 2
Dry Contact
0-10 VDC or 4-20 mA Dehumidification
Ratiometric input required
Ratiometric input required
X
X
X
X7
X8
Digital Outputs – Relay (SPST, Normally Open, 230 VAC 3 Amp)
#
DO 1
DO 2
DO 3
DO 4
Point
Compressor 5
Compressor 6
Digital Outputs – Triac (24 VAC, .5 Amp)
Point
#
DO 5
DO 6
Comments
Comments
Note – Expansion Module A dipswitches are always set to address #1. Dipswitch #6 must be in
the on position when it is the last module.
Table 9: SCU - Expansion Module B
SCU - Expansion Module B
Heating, F&BP Dampers
Universal Inputs/Outputs
#
X1
X2
X3
X4
X5
X6
X7
X8
DI
AI
DO
AO
Point
Comments
X
X
Heating Valve
F&BP Damper
0-10 VDC
0-10 VDC
Digital Outputs – Relay (SPST, Normally Open, 230 VAC 3 Amp)
#
DO 1
DO 2
DO 3
DO 4
Point
Heat Stage 1
Heat Stage 2
Heat Stage 3
Heat Stage 4
Comments
Digital Outputs – Triac (24 VAC, .5 Amp)
#
DO 5
DO 6
Point
Heat Stage 5
Heat Stage 6
Comments
Pilot Relay
Pilot Relay
Note – Expansion Module B dipswitches are always set to address #2. Dipswitch #6 must be in
the on position when it is the last module.
24
McQuay IM 919
Controller Inputs/Outputs
Table 10: SCU - Expansion Module C
SCU - Expansion Module C
One Compressor Per Circuit
Universal Inputs/Outputs
#
X1
X2
X3
X4
X5
X6
X7
X8
DI
X
X
X
X
X
X
X
X
AI
DO
AO
Point
Low Pressure 3
Low Pressure 4
High Pressure 3
High Pressure 4
Low Pressure 5
Low Pressure 6
High Pressure 5
High Pressure 6
Comments
Dry Contact
Dry Contact
Dry Contact
Dry Contact
Dry Contact
Dry Contact
Dry Contact
Dry Contact
Digital Outputs – Relay (SPST, Normally Open, 230 VAC 3 Amp)
#
DO 1
DO 2
DO 3
DO 4
Point
Comments
Digital Outputs – Triac (24 VAC, .5 Amp)
#
DO 5
DO 6
Point
Comments
Note – Expansion Module C dipswitches are always set to address #3. Dipswitch #6 must be in
the on position when it is the last module.
McQuay IM 919
25
Field Wiring
Field Wiring
Below are descriptions of the various options and features that may require field wiring to the
MicroTech III controller. Refer to the job plans and specifications and the as-built wiring
schematics for information regarding the specific unit.
Field Output Signals
The following outputs may be available for field connections to a suitable device.
Remote Alarm Output
The Remote Alarm Output (MCB-DO9) supplies 24 VAC to terminal 115 on the field terminal
block (TB2) when the output is on. To use this signal, wire the coil of a field supplied and
installed 24 VAC pilot relay across terminals 115 and 117 on TB2. When this output is on, 24
VAC is supplied from the T3 control transformer through the output relay to energize the field
relay. Refer to the as-built wiring diagrams.
The digital alarm output indicates the alarm group that contains the highest priority active
alarm. This output (MCB-DO9) is On when no alarms are active. The options for the action of
this output when an alarm in a group occurs are On, Fast Blink, Slow Blink, or Off. These
can be edited via the Alarm Out Config menu in the Extended menus on keypad/display. The
default values for the three groups of alarms are:
Warnings
-
Off
Problems
-
Slow Blink
Faults
Fast Blink
-
A user could eliminate any signal of a particular group of alarms through this output by
selecting On for that alarm group in the keypad/display.
Fan Operation
The Fan Operation Output (MCB-DO10) supplies 24 VAC to terminal 116 on the field
terminal block (TB2) when the output is on. To use this signal, wire the coil of a field supplied
and installed 24 VAC pilot relay across terminals 116 and 117 on TB2. When this output is on,
24 VAC is supplied from the T3 control transformer through the output relay to energize the
field relay. Refer to the as-built wiring diagrams.
The Fan Operation output is on when the unit is not Off and when both the unit is Off and
airflow is detected. It is off when the unit is off and airflow is not detected.
Cooling Only Units
For cooling only VAV systems, the VAV Box Output can override zone thermostat control and
drive the VAV boxes fully open to facilitate air circulation during the Recirc operating state.
During this time, the VAV Box Output is in the OFF (or heat) position (field-installed pilot
relay de-energized). VAV units have a “post heat” control feature that forces the VFD speed to
a minimum before turning on the VAV Box Output when the Recirc operating state is
complete. Post heat operation prevents excessive duct static pressure that could otherwise
occur when the zone thermostats regain VAV box control. The setting of a “post heat” timer
determines the duration of post heat operation. This timer is set to zero at the factory and must
be set to a non-zero value to enable the “post heat” function.
26
McQuay IM 919
Field Wiring
Units with Modulating Heat
The VAV Box Output should be used to switch the VAV boxes between heating and cooling
control. While the unit is in Startup, Recirc, or Heating operating state (UnocHtg, MWU, or
Heating), the VAV Box Output is in the OFF (or heat) position (field-installed pilot relay deenergized) switching the VAV boxes into heating operation.
VAV units have a “post heat” control feature that forces the VFD speed to a minimum before
closing the VAV Box Output when the unit leaves the Recirc or Heating operating state. “Post
heat” operation prevents excessive duct static pressure that could otherwise occur when the
zone thermostats regain VAV box control. When the unit is not in Startup, Recirc, or Heating
operating state, the VAV Box Output is in the ON (or cool) position (field-supplied pilot relay
energized) switching the boxes to cooling control.
Staged Cooling Outputs
Rooftop air handlers can be ordered with factory-installed evaporator coils and the capability
to control up to eight stages of field-supplied cooling equipment. The MicroTech III outputs
designated for these applications are DO 1-4 and DO 7,8 on the MCB and DO 1,2 on
Expansion board A. These outputs are wired to terminal block TB4 in the main control panel
for connection to the field supplied condensing unit. Refer to the as-built wiring schematics
for the unit
Outdoor Damper
When applicable the Outdoor Damper Output supplies 24 VAC to terminal 119 on the field
terminal block (TB2) when the output is on. To use this signal, wire the coil of a field supplied
and installed 24 VAC pilot relay across terminals 119 and 117 on TB2. When this output is on,
24 VAC is supplied from the T3 control transformer through the output relay to energize the
field relay. Refer to the as-built wiring diagrams.
Pump Signal
When applicable the Pump Signal Output supplies 24 VAC to terminal 113 on the field
terminal block (TB2) when the output is on. To use this signal, wire the coil of a field supplied
and installed 24 VAC pilot relay across terminals 113 and 117 on TB2. When this output is on,
24 VAC is supplied from the T3 control transformer through the output relay to energize the
field relay. Refer to the as-built wiring diagrams.
Figure 21: Fan Operation Output Wiring Diagram
McQuay IM 919
27
Field Wiring
Field Analog Input Signals
The following inputs may be available for field connections to a suitable device.
Zone Temperature Sensor Packages
A zone temperature sensor (ZNT1) is optional for all units except for the 100% outdoor air
CAV-ZTC unit in which case one is required. In all unit configurations, however, a zone
temperature sensor is required to take advantage of any of the following standard controller
features:
• Unoccupied heating or cooling
• Pre-occupancy purge
• Discharge air reset based on space temperature (DAC units only)
• Remote timed tenant override
• Remote set point adjustment (CAV-ZTC units only)
A Zone Setpoint Source (TstatSptSrc=No/Yes) parameter is provided on the keypad/display to
allow for setting the setpoint via the zone thermostat input. The menu is located in the Zone
Temp Setup menu of the Extended Menu section. When TstatSptSrc=No, the Zone Cooling
Spt and the Zone Heating Spt may be set through the keypad or via a network signal (all
units). In this case these setpoints are changed whenever the network or keypad value changes.
When TstatSptSrc=Yes these setpoints can only be adjusted through the zone thermostat (zone
control units). Heating and cooling setpoints must not overlap. The Zone Heating Spt must be
equal to or less than the Zone Cooling Spt. If a conflict occurs from values entered via the
keypad or network, the Zone Heating Spt is automatically adjusted down to eliminate the
conflict.
When TstatSptSrc=No, the Zone Heating and Cooling setpoints may be changed manually by
changing the setpoint displayed on the keypad.
When TstatSptSrc=Yes, the Zone Cooling Setpoint is set through a setpoint adjustment
included with a wall mounted space sensor. When the Zone Cooling Setpoint is changed by
more than 0.5 degrees through the wall mounted sensor, the Zone Heating Setpoint is raised or
lowered the same amount so that the difference between the Cooling (ZnClgSpt) and Heating
(ZnHtgSpt) setpoints does not change. The setpoint adjustment is a resistance value that varies
from 5000 ohm to 15000 ohms.
Figure 22: MicroTech III Wallstat Resistance vs. Setpoint
16000
14000
10000
(
)
12000
8000
Series1
6000
4000
2000
0
45
50
55
60
65
70
75
80
85
Setpoint (F)
28
McQuay IM 919
Field Wiring
Resistance vs. Temperature for Setpoint Adjustment on the MT III
Ohms
T (°F)
T (°C)
5000
50
10
6000
54
12
7000
57
14
8000
61
16
9000
64
18
10000
68
20
11000
72
22
12000
75
24
13000
79
26
14000
82
28
15000
86
30
Zone Sensor w/o Remote Set Point Adjustment
The standard MicroTech III room temperature sensor package that does not include set point
adjustment can be used with any applied rooftop MicroTech III control configuration. It
includes a tenant override button. This zone sensor must be field installed and field-wired to
the unit using twisted pair, shielded cable (Belden 8761 or equivalent).
Zone Sensor with Remote Set Point Adjustment
The standard MicroTech III room temperature sensor package equipped with a set point
adjustment potentiometer is available to use with CAV-ZTC units. This sensor package also
includes a tenant override button. This zone sensor package must be field installed and field
wired to the unit using twisted, shielded cable. Four conductors with a shield wire are
required. Cable with 22 AWG conductors (Belden 8761 or equivalent) is sufficient.
Tenant Override (Timed)
The tenant override button provided with the two optional zone temperature sensor packages
can be used to override unoccupied operation for a programmed time period. This time period
is adjustable between 0 and 5 hours using the Tenant Override parameter in the Timer Settings
menu in the Extended Menus of the keypad/display (default is 2 hours). Except for the fact
that it is temporary, tenant override operation is identical to occupied operation. Pressing and
releasing the push button switch on the sensor momentarily shorts zone temperature sensor
ZNT1, resetting and starting the override timer. The unit then starts up and runs until the
override timer times out.
Note – Note: Hold the button in for at least 1 second but not more than 30 seconds
McQuay IM 919
29
Field Wiring
Figure 23: Zone Sensor without Setpoint Adjustment
ZONE SENSOR W/O
REMOTE SETPOINT
ADJUSTMENT
30
McQuay IM 919
Field Wiring
Figure 24: Zone Sensor with Setpoint Adjustment
ZONE SENSOR W/
REMOTE SETPOINT
ADJUSTMENT
C
S
P
McQuay IM 919
31
Field Wiring
External Outdoor Air Damper Reset Signal
On units equipped with a 0-100% modulating economizer the minimum outside air damper
position set point can be reset by an external voltage or current signal. The external reset
method can be selected with the Min OA Reset parameter in the Min OA Damper menu in the
Standard Menus via the controller keypad/display. External reset requires a field supplied reset
signal in the range of 0-10 VDC or 0-20 mA wired to terminals 124 and 125 on the field
terminal block (TB2). Refer to the unit wiring diagrams for wiring termination details. If the
external reset option is selected, the controller linearly resets the outside air damper position
set point between user-programmed minimum (Demand Control Ventilation Limit) and
maximum (Ventilation Limit) values as the field supplied reset signal varies between a
minimum and maximum (or maximum to minimum) value. The external reset signal must be
field-wired to the unit using a twisted pair, shielded cable (Belden 8761 or equivalent). Cable
with 22 AWG conductors is sufficient.
Figure 25: External Outdoor Air Damper Reset Signal Wiring Diagram
Humidity Sensors
Either a wall mount or duct mount Humidity sensor is available. The sensor must be wired to
terminals 126, 127 and 131 on the unit field terminal block (TB2). Terminal 126 is wired to
OUT, terminal 127 to COM and terminal 131 to IN on the humidity sensor. These terminals
are factory wired to the Expansion Board A AIX6. The sensor can deliver 0-10VDC or 020mA, the type of signal (VDC or mA) and the 0% and 100% RH values are adjustable via the
Dehum Setup menu in the Extended Menu on the keypad/display.
Figure 26: Humidity Sensor Wiring Diagram
32
McQuay IM 919
Field Wiring
Field Digital Input Signals
The following inputs may be available for field connections to a suitable device.
External Time Clock or Tenant Override
There are several methods of switching the rooftop unit between occupied and unoccupied
operation. It can be done by the controller internal schedule, a network schedule, an external
time clock, or a tenant override switch.
If the internal schedule or a network schedule is used, field wiring is not required.
An external time clock or a tenant override switch can be used by installing a set of dry
contacts across terminals 101 and 102 on the field terminal block (TB2). When these contacts
close, 24 VAC is applied to binary input MCB-DI3, overriding any internal or network
schedule and placing the unit into occupied operation (provided the unit is not manually
disabled). When the contacts open (24 VAC is removed from MCB-DI3) the unit acts
according to the controller internal time schedule or a network schedule. Refer to the unit
wiring diagrams for specific wiring termination details.
Figure 27: Time Clock/Tenant Override Wiring Diagram
Emergency Shutdown
The terminals 105 & 106 on TB2 can be used for any field supplied component that requires a
unit emergency shutdown. When these terminals are used, the factory installed jumper must be
removed.
Figure 28: Emergency Shutdown Wiring Diagram
McQuay IM 919
33
Cooling: Multistage
Cooling: Multistage
Compressor Staging
The staging sequences named Std-1 through Std-6 or Alt-1 through Alt-6 in the tables below
indicate what compressors will be on when cooling stage is set to each stage. A single staging
sequence will be active at any one time. The method for deciding which staging sequence is
active is described for each compressor configuration below.
Two Unequal Sized Compressors, Two Circuits, Three Stages
Only one sequence is provided so the user makes no selections.
• Total cooling stages is 3.
• If neither circuit is disabled, Maximum Cooling stages is set to 3.
• If circuit 2 is disabled, Maximum Cooling stages is set to 1.
• If circuit 1 is disabled, Maximum Cooling stages is set to 2.
• If circuit is disabled, it is not re-enabled until the stage timer clears.
Table 11: Standard Staging
Staging Sequence
Std-1
StgdClgCap
Standard Staging
Stage 1 Compressor
Stage 2 Compressors
1
33%
Stage 3 Compressors
2
67%
1,2
100%
Two Small Comps on Circuit # 1, One Large Comp on Circuit # 2, Four Stages
Only one sequence is provided so the user makes no selections.
• Total cooling stages is set to 4.
• If neither circuit is disabled, the staging sequence is Std-1 if compressor # 1 has fewer hours
than compressor # 3, and the staging sequence is Std-2 if compressor # 1 does not have
fewer hours than compressor # 3.
• Maximum cooling stages is set to 4.
• If Circuit #1 is disabled, the staging sequence is set to Alt-1 after the stage timer, unless
Comp #2 is already on. Then the switch to Alt-1 happens immediately. Maximum cooling
stages is set to 1.
• If Circuit #2 is disabled, the staging sequence is set to Std-1 if comp #1 has fewer hours than
comp #3, and the staging sequence is set to Std-2 if comp #1 does not have fewer hours than
comp #3, after the stage time. Maximum cooling stages is set to 2.
• Any comp on a disabled circuit stays off if it is already off and is turned off if it is on.
• The staging sequence is changed based on Run Time only when the number of stages stage
is zero or Maximum cooling stages. This means that disabling and re-enabling the
compressors or turning the unit off and on may be necessary to cause sequence changes.
• Alt-1 is used if circuit # 1 is disabled.
• If a circuit is disabled, Maximum cooling stages is set to 2.
Table 12: Standard Staging
Staging Sequence
Std-1
Std-2
StgdClgCap
34
Stage 1
Standard Staging
Stage 2
Stage 3
Stage 4
Compressor
Compressors
Compressors
Compressors
1
3
25%
1,3
3,1
50%
2,3
1,2
75%
1,2,3
1,2,3
100%
McQuay IM 919
Cooling: Multistage
Table 13: Alternate Staging
Staging Sequence
Alt-1
StgdClgCap
Stage 1
Alternate Circuit Staging
Stage 2
Stage 3
Stage 4
Compressor
Compressors
Compressors
Compressors
0
0%
2
50%
1,2
75%
1,2,3
100%
Two Equal Sized Compressors, Two Circuits
The user selects the following:
• Lead Circuit = Auto, # 1 or # 2.
• A separate alternate circuit is not provided for this configuration
• Total cooling stages = 2
• If Lead Circuit is set to Auto and neither circuit is disabled, the compressor sequence is Std1 if compressor # 1 has fewer hours than compressor # 2, and the staging sequence is Std-2
if compressor # 1 does not have fewer hours than compressor # 2. Maximum cooling stages
is set to 2.
• If Lead Circuit is set to # 1 or Circuit # 2 is disabled, sequence Std-1 is used.
• If Lead Circuit is set to # 2 or Circuit # 1 is disabled, sequence Std-2 is used.
• The Compressor Sequence changes only when the compressor stage is Maximum cooling
stages or zero. This means that disabling and re-enabling the compressors or turning the unit
off and on may be necessary to cause sequence changes.
• If a circuit is disabled, Maximum cooling is set to one. The compressor on the disabled
circuit stays off if it is already off and is turned off if it is on.
Table 14: Standard Staging
Staging Sequence
Standard Staging
Stage 1 Compressor
Stage 2 Compressors
Std-1
Std-2
StgdClgCap
1
2
50%
1,2
1,2
100%
Three Equal Sized Compressors, Three Circuits, No WRV
• Total cooling stages = 3
• Maximum cooling stages is always set to 3.
• The Staging sequence is the Standard sequence that contains the enabled Stage 1
Compressor with the fewest run hours. Compressors in disabled circuits are ignored when
only enabled compressor run hours are compared.
• The Compressor Sequence changes only when the compressor stage is Maximum cooling
stages or zero. This means that disabling and re-enabling the compressors or turning the unit
off and on may be necessary to cause sequence changes.
• The same staging sequence is used whether a circuit is disabled or not. This means that units
will remain at a stage for an extra stage time when staging up if a disabled circuit is added at
that stage. It also means that units will remain at a stage for an extra stage time when staging
down if a disabled circuit is turned off at that stage.
• Any compressor on the disabled circuit stays off if it is already off and is turned off if it is
on.
Table 15: Standard Staging
Staging Sequence
Std-1
Std-2
Std-3
StgdClgCap
McQuay IM 919
Standard Staging
Stage 1 Compressor
Stage 2 Compressors
1
2
3
33%
1,2
2,3
1,3
67%
Stage 3 Compressors
1,2,3
1,2,3
1,2,3
100%
35
Cooling: Multistage
Three Equal Sized Compressors, Three Circuits, Water Regulating Valve
• Total cooling stages = 3.
• Maximum cooling stages is always set to 3.
• If both circuit # 1 and circuit # 2 are enabled, the staging sequence is Std-1 if compressor # 1
has fewer hours than compressor # 2, and the staging sequence is Std-2 if compressor # 1
does not have fewer hours than compressor # 2.
• If Circuit # 1 is disabled, the staging sequence is Std-2.
• If Circuit # 2 is disabled, the staging sequence is Std-1.
• If both circuit # 1 and circuit # 2 are disabled, the staging sequence is Std-1. Only
compressor # 3 is used.
• The Compressor Sequence changes based on Run Time only when the compressor stage
equals Maximum Cooling stage or zero. This means that disabling and re-enabling the
compressors or turning the unit off and on may be necessary to cause sequence changes.
• In order to keep either compressor # 1 or # 2 on, the compressor sequence changes
immediately if a circuit is disabled. This will result is compressors being turned off and
others being turned on in this emergency condition.
• The same staging sequence is used whether a circuit is disabled or not. This means that units
will remain at a stage for an extra stage time when staging up if a disabled circuit is added at
that stage. It also means that units will remain at a stage for an extra stage times when
staging down if a disabled circuit is turned off at that stage.
• Any compressor on a disabled circuit stays off if it is already off and is turned off if it is on.
Table 16: Standard Staging
Staging Sequence
Standard Staging
Stage 1 Compressors
Stage 2 Compressors
Std-1
Std-2
StgdClgCap
1
2
33%
1,3
2,3
67%
Stage 3 Compressors
1,2,3
1,2,3
100%
Four Equal Sized Compressors, Two Circuits
The user selects the following:
• Staging Type = Standard or Alternate Staging
• Lead Circuit = Auto, # 1 or # 2.
• Total cooling stages = 4
• If Lead Circuit is set to Auto and neither circuit is disabled, the Staging sequence is the
Standard or Alternate sequence that contains the Stage 1 Compressor with the fewest run
hours. Maximum cooling stages is set to 4.
• If Lead Circuit is set to # 1 and Circuit # 2 is enabled, the Staging sequence is Std-1 or Std-3
that contains the Stage 1 Compressor with fewer run hours.
• If Lead Circuit is set to # 1 and Circuit # 2 is disabled, the Staging sequence is Alt-1 or Alt3 that contains the Stage 1 Compressor with fewer run hours.
• If Lead Circuit is set to # 2 and Circuit # 1 is enabled, the Staging sequence is Std-2 or Std-4
that contains the Stage 1 Compressor with fewer run hours.
• If Lead Circuit is set to # 2 and Circuit # 1 is disabled, the Staging sequence is Alt-2 or Alt4 that contains the Stage 1 Compressor with fewer run hours.
• The Compressor Sequence changes only when the compressor stage equals Maximum
cooling stages or zero. This means that disabling and re-enabling the compressors or turning
the unit off and on may be necessary to cause sequence changes.
36
McQuay IM 919
Cooling: Multistage
• If a circuit is disabled, Maximum cooling stages is set to two. Any compressor on the
disabled circuit stays off if it is already off and is turned off if it is on.
• If dehumidification is active, Alternate Staging is used regardless of the Staging Type=
setting.
Table 17: Standard Staging
Staging Sequence
Std-1
Std-2
Std-3
Std-4
StgdClgCap
Stage 1
Standard Staging
Stage 2
Stage 3
Stage 4
Compressors
Compressors
Compressors
Compressors
1
2
3
4
25%
1,2
2,3
3,4
1,4
50%
1,2,3
2,3,4
1,3,4
1,2,4
75%
1,2,3,4
1,2,3,4
1,2,3,4
1,2,3,4
100%
Table 18: Alternate Staging
Staging Sequence
Alt-1
Alt-2
Alt-3
Alt-4
StgdClgCap
Stage 1
Alternate Staging
Stage 2
Stage 3
Stage 4
Compressors
Compressors
Compressors
Compressors
1
2
3
4
25%
1,3
2,4
1,3
2,4
50%
1,2,3
1,2,4
1,3,4
2,3,4
75%
1,2,3,4
1,2,3,4
1,2,3,4
1,2,3,4
100%
Four Equal Sized Compressors, Four Circuits, No WRV
• Total cooling stage = 4.
• Maximum cooling stages is always set to 4.
• The Staging sequence is the Standard sequence that contains the enabled Stage 1
Compressor with the fewest run hours. Compressors in disabled circuits are ignored when
only enabled compressor run hours are compared. Maximum cooling stages is set to 4.
• The Compressor Sequence changes only when the compressor stage equals Maximum
cooling stages or zero. This means that disabling and re-enabling the compressors or turning
the unit off and on may be necessary to cause sequence changes.
• The same staging sequence is used whether a circuit is disabled or not. This means that units
will remain at a stage for an extra stage time when staging up if a disabled circuit is added at
that stage. It also means that units will remain at a stage for an extra stage times when
staging down if a disabled circuit is turned off at that stage.
• Any compressor on the disabled circuit stays off if already off and is turned off if on.
Table 19: Standard Staging
Staging Sequence
Std-1
Std-2
Std-3
Std-4
StgdClgCap
Stage 1
Standard Staging
Stage 2
Stage 3
Stage 4
Compressors
Compressors
Compressors
Compressors
1
2
3
4
25%
1,2
2,3
3,4
1,4
50%
1,2,3
2,3,4
1,3,4
1,2,4
75%
1,2,3,4
1,2,3,4
1,2,3,4
1,2,3,4
100%
Four Equal Sized Compressors, Four Circuits, Water Regulating Valve
Only one sequence is provided so the user makes no selections.
• Total cooling stages = 4.
• Maximum cooling stages is always set to 4.
• If neither circuit # 1 nor circuit # 2 is disabled, the staging sequence is Std-1 if compressor #
1 has fewer hours than compressor # 2, and the staging sequence is Std-2 if compressor # 1
does not have fewer hours than compressor # 2.
McQuay IM 919
37
Cooling: Multistage
• If Circuit # 1 is disabled, the staging sequence is Std-2.
• If Circuit # 2 is disabled, the staging sequence is Std-1.
• If both circuit # 1 and circuit # 2 are disabled, the staging sequence is Std-1. Only
compressors 3 and 4 are used.
• The Compressor Sequence changes based on Run Time only when the compressor stage
equals Maximum cooling stages or zero. This means that disabling and re-enabling the
compressors or turning the unit off and on may be necessary to cause sequence changes.
• The compressor sequence changes immediately if a circuit is disabled to keep either
compressor # 1 or # 2 on. This will result in compressors being turned off and others being
turned on in this emergency condition.
• The same staging sequence is used whether a circuit is disabled or not. This means that units
will remain at a stage for an extra stage time when staging up if a disabled circuit is added at
that stage. It also means that units will remain at a stage for an extra stage time when staging
down if a disabled circuit is turned off at that stage.
• Any compressor on a disabled circuit stays off if it is already off and is turned off if it is on.
Table 20: Standard Staging
Staging Sequence
Std-1
Std-2
StgdClgCap
Stage 1
Standard Staging
Stage 2
Stage 3
Stage 4
Compressors
Compressors
Compressors
Compressors
1
2
25%
1,4
2,3
50%
1,3,4
2,3,4
75%
1,2,3,4
1,2,3,4
100%
Six Equal Sized Compressors, Two Circuits
The user selects the following:
• Staging Type = Standard or Alternate Staging.
• Lead Circuit = Auto, # 1 or # 2.
• Total cooling stages = 6.
• If Lead Circuit is set to Auto and neither circuit is disabled, the Staging sequence is the
Standard or Alternate sequence that contains the Stage 1 Compressor with the fewest run
hours. Maximum cooling stages is set to 6.
• If Lead Circuit is set to # 1 and Circuit # 2 is enabled, the Staging sequence is Std-1, Std-3,
or Std-5 that contains the Stage 1 Compressor with the fewest run hours.
• If Lead Circuit is set to # 1 and Circuit # 2 is disabled, the Staging sequence is Alt-1, Alt-3,
or Alt-5 that contains the Stage 1 Compressor with the fewest run hours.
• If Lead Circuit is set to # 2 and Circuit # 1 is enabled, the Staging sequence is Std-2, Std-4,
or Std-6 that contains the Stage 1 Compressor with the fewest run hours.
• If Lead Circuit is set to # 2 and Circuit # 1 is disabled, the Staging sequence is Alt-2, Alt-4,
or Alt-6 that contains the Stage 1 Compressor with the fewest run hours.
• The Compressor Sequence changes only when the compressor stage equals Maximum
cooling stages or zero. This means that disabling and re-enabling the compressors or turning
the unit off and on may be necessary to cause sequence changes.
• If a circuit is disabled, Maximum cooling stages is set to three. Any compressor on the
disabled circuit stays off if it is already off and is turned off if it is on.
• If dehumidification is active, Alternate Staging is used regardless of the Staging Type=
setting.
38
McQuay IM 919
Cooling: Multistage
Table 21: Standard Staging
Staging Sequence
Std-1
Std-2
Std-3
Std-4
Std-5
Std-6
StgdClgCap
Stage 1
Stage 2
Comps
Comps
1
2
3
4
5
6
17%
1,2
2,3
3,4
4,5
5,6
1,6
33%
Standard Staging
Stage 3
Stage 4
Comps
Comps
1,2,3
2,3,4
3,4,5
4,5,6
1,5,6
1,2,6
50%
1,2,3,4
2,3,4,5
3,4,5,6
1,4,5,6
1,2,5,6
1,2,3,6
67%
Stage 5
Comps
Stage 6
1,2,3,4,5
2,3,4,5,6
1,3,4,5,6
1,2,4,5,6
1,2,3,5,6
1,2,3,4,6
83%
1,2,3,4,5,6
1,2,3,4,5,6
1,2,3,4,5,6
1,2,3,4,5,6
1,2,3,4,5,6
1,2,3,4,5,6
100%
Stage 5
Comps
Stage 6
1,2,3,4,5
1,2,3,4,6
1,3,4,5,6
2,3,4,5,6
1,2,3,5,6
1,2,4,5,6
83%
1,2,3,4,5,6
1,2,3,4,5,6
1,2,3,4,5,6
1,2,3,4,5,6
1,2,3,4,5,6
1,2,3,4,5,6
100%
Comps
Table 22: Alternate Staging
Staging Sequence
Alt-1
Alt-2
Alt-3
Alt-4
Alt-5
Alt-6
StgdClgCap
Stage 1
Stage 2
Comps
Comps
1
2
3
4
5
6
17%
1,3
2,4
3,5
4,6
1,5
2,6
33%
Alternate Staging
Stage 3
Stage 4
Comps
Comps
1,3,5
2,4,6
1,3,5
2,4,6
1,3,5
2,4,6
50%
1,2,3,5
1,2,4,6
1,3,4,5
2,3,4,6
1,3,5,6
2,4,5,6
67%
Comps
Six Equal Sized Compressors, Six Circuits, No WRV
Only one sequence is provided so the user makes no selections.
• Total cooling stages = 6.
• Maximum cooling stages is always set to 6.
• The Staging sequence is the Standard sequence that contains the enabled Stage 1
Compressor with the fewest run hours. Compressors in disabled circuits are ignored when
only enabled compressor run hours are compared.
• The Compressor Sequence changes only when the compressor stage is Maximum cooling
stages or zero. This means that disabling and re-enabling the compressors or turning the unit
off and on may be necessary to cause sequence changes.
• The same staging sequence is used whether a circuit is disabled or not. This means that units
will remain at a stage for an extra stage time when staging up if a disabled circuit is added at
that stage. It also means that units will remain at a stage for an extra stage times when
staging down if a disabled circuit is turned off at that stage.
• Any compressor on the disabled circuit stays off if it is already off and is turned off if it is
on.
Table 23: Standard Staging
Staging Sequence
Std-1
Std-2
Std-3
Std-4
Std-5
Std-6
StgdClgCap
McQuay IM 919
Stage 1
Stage 2
Comps
Comps
1
2
3
4
5
6
17%
1,2
2,3
3,4
4,5
5,6
1,6
33%
Standard Staging
Stage 3
Stage 4
Comps
Comps
1,2,3
2,3,4
3,4,5
4,5,6
1,5,6
1,2,6
50%
1,2,3,4
2,3,4,5
3,4,5,6
1,4,5,6
1,2,5,6
1,2,3,6
67%
Stage 5
Comps
Stage 6
1,2,3,4,5
2,3,4,5,6
1,3,4,5,6
1,2,4,5,6
1,2,3,5,6
1,2,3,4,6
83%
1,2,3,4,5,6
1,2,3,4,5,6
1,2,3,4,5,6
1,2,3,4,5,6
1,2,3,4,5,6
1,2,3,4,5,6
100%
Comps
39
Cooling: Multistage
Six Equal Sized Compressors, Six Circuits, Water Regulating Valve (WRV)
Only one sequence is provided so the user makes no selections.
• Total cooling stages = 6.
• Maximum cooling stages is always set to 6.
• If both circuit # 1 and circuit # 2 are enabled, the staging sequence is Std-1 if compressor # 1
has fewer hours than compressor # 2, and the staging sequence is Std-2 if compressor # 1
does not have fewer hours than compressor # 2.
• If Circuit # 1 is disabled, the staging sequence is Std-2.
• If Circuit # 2 is disabled, the staging sequence is Std-1.
• If both circuit # 1 and circuit # 2 are disabled, the staging sequence is Std-1. Only
compressors 3, 4, 5, and 6 are used.
• The Compressor Sequence changes based on Run Time only when the compressor stage
equals Maximum cooling stages or zero. This means that disabling and re-enabling the
compressors or turning the unit off and on may be necessary to cause sequence changes.
• The compressor sequence changes immediately if a circuit is disabled to keep either
compressor # 1 or # 2 on. This will result is compressors being turned off and others being
turned on in this emergency condition.
• The same staging sequence is used whether a circuit is disabled or not. This means that units
will remain at a stage for an extra stage time when staging up if a disabled circuit is added at
that stage. It also means that units will remain at a stage for an extra stage times when
staging down if a disabled circuit is turned off at that stage.
• Any compressor on a disabled circuit stays off if it is already off and is turned off if it is on.
Table 24: Standard Staging
Staging Sequence
Std-1
Std-2
StgdClgCap
Stage 1
Stage 2
Comps
Comps
1
2
17%
1,4
2,3
33%
Standard Staging
Stage 3
Stage 4
Comps
Comps
1,4,5
2,3,6
50%
1,4,5,6
2,3,5,6
67%
Stage 5
Comps
Stage 6
1,3,4,5,6
2,3,4,5,6
83%
1,2,3,4,5,6
1,2,3,4,5,6
100%
Comps
Eight Equal Sized Compressors, Two Circuits
The user selects the following:
• Staging Type = Standard or Alternate Staging.
• Lead Circuit = Auto, # 1 or # 2.
• Total cooling stages = 8.
• If Lead Circuit is set to Auto and neither circuit is disabled, the Staging sequence is the
Standard or Alternate sequence that contains the Stage 1 Compressor with the fewest run
hours. Maximum cooling stages is set to 8.
• If Lead Circuit is set to # 1 and Circuit # 2 is enabled, the Staging sequence is Std-1, Std-3,
Std-5 or Std-7 that contains the Stage 1 Compressor with the fewest run hours.
• If Lead Circuit is set to # 1 and Circuit # 2 is disabled, the Staging sequence is Alt-1, Alt-3,
Alt-5,or Alt-7 that contains the Stage 1 Compressor with the fewest run hours.
• If Lead Circuit is set to # 2 and Circuit # 1 is enabled, the Staging sequence is Std-2, Std-4,
Std-6 or Std-8 that contains the Stage 1 Compressor with the fewest run hours.
• If Lead Circuit is set to # 2 and Circuit # 1 is disabled, the Staging sequence is Alt-2, Alt-4,
Alt-6, or Alt-8 that contains the Stage 1 Compressor with the fewest run hours.
• The Compressor Sequence changes only when the compressor stage equals Maximum
cooling stages or zero. This means that disabling and re-enabling the compressors or turning
the unit off and on may be necessary to cause sequence changes.
40
McQuay IM 919
Cooling: Multistage
• If a circuit is disabled, Maximum cooling stages is set to four. Any compressor on the
disabled circuit stays off if it is already off and is turned off if it is on.
• If dehumidification is active, Alternate Staging is used regardless of the Staging Type=
setting.
Table 25: Standard Staging
Staging
Sequence
Stage 1
Comps
Stage 2
Comps
Stage 3
Comps
Std-1
Std-2
Std-3
Std-4
Std-5
Std-6
Std-7
Std-8
ClgCap
1
2
3
4
5
6
7
8
13%
1,2
1,2
3,4
3,4
5,6
5,6
7,8
7,8
25%
1,2,3
1,2,8
2,3,4
3,4,5
4,5,6
5,6,7
1,7,8
6,7,8
38%
Standard Staging
Stage 4
Stage 5
Comps
Comps
1,2,3,4
1,2,7,8
1,2,3,4
3,4,5,6
3,4,5,6
5,6,7,8
1,2,7,8
5,6,7,8
50%
1,2,3,4,5
1,2,3,7,8
1,2,3,4,8
2,3,4,5,6
3,4,5,6,7
1,5,6,7,8
1,2,6,7,8
4,5,6,7,8
63%
Stage 6
Comps
Stage 7
Comps
Stage 8 Comps
1,2,3,4,5,6
1,2,3,4,7,8
1,2,3,4,7,8
1,2,3,4,5,6
3,4,5,6,7,8
1,2,5,6,7,8
1,2,5,6,7,8
3,4,5,6,7,8
75%
1,2,3,4,5,6,7
1,2,3,4,5,7,8
1,2,3,4,6,7,8
1,2,3,4,5,6,8
1,3,4,5,6,7,8
1,2,3,5,6,7,8
1,2,4,5,6,7,8
2,3,4,5,6,7,8
88%
1,2,3,4,5,6,7,8
1,2,3,4,5,6,7,8
1,2,3,4,5,6,7,8
1,2,3,4,5,6,7,8
1,2,3,4,5,6,7,8
1,2,3,4,5,6,7,8
1,2,3,4,5,6,7,8
1,2,3,4,5,6,7,8
100%
Stage 6
Comps
Stage 7
Comps
Stage 8 Comps
1,2,3,5,6,7
1,2,3,4,6,8
1,3,4,5,7,8
1,2,3,4,6,8
1,2,3,5,6,7
2,4,5,6,7,8
1,3,4,5,7,8
2,4,5,6,7,8
75%
1,2,3,4,5,6,7
1,2,3,4,5,6,8
1,2,3,4,5,7,8
1,2,3,4,6,7,8
1,2,3,5,6,7,8
1,2,4,5,6,7,8
1,3,4,5,6,7,8
2,3,4,5,6,7,8
88%
1,2,3,4,5,6,7,8
1,2,3,4,5,6,7,8
1,2,3,4,5,6,7,8
1,2,3,4,5,6,7,8
1,2,3,4,5,6,7,8
1,2,3,4,5,6,7,8
1,2,3,4,5,6,7,8
1,2,3,4,5,6,7,8
100%
Table 26: Alternate Staging
Staging
Sequence
Stage 1
Comps
Stage 2
Comps
Stage 3
Comps
Std-1
Std-2
Std-3
Std-4
Std-5
Std-6
Std-7
Std-8
ClgCap
1
2
3
4
5
6
7
8
13%
1,3
2,4
1,3
2,4
5,7
6,8
5,7
7,8
25%
1,3,5
2,4,6
1,3,7
2,4,8
1,5,7
2,6,8
3,5,7
4,6,8
38%
Standard Staging
Stage 4
Stage 5
Comps
Comps
1,3,5,7
2,4,6,8
1,3,5,7
2,4,6,8
1,3,5,7
2,4,6,8
1,3,5,7
2,4,6,8
50%
1,2,3,5,7
1,2,4,6,8
1,3,4,5,7
2,3,4,6,8
1,3,5,6,7
2,4,5,6,8
1,3,5,7,8
2,4,6,7,8
63%
Eight Equal Sized Compressors, Eight Circuits, No WRV
Only one sequence is provided so the user makes no selections.
• Total cooling stages = 8.
• Maximum cooling stages is always set to 8.
• The Staging sequence is the Standard sequence that contains the enabled Stage 1
Compressor with the fewest run hours. Compressors in disabled circuits are ignored when
only enabled compressor run hours are compared.
• The Compressor Sequence changes only when the compressor stage is Maximum cooling
stages or zero. This means that disabling and re-enabling the compressors or turning the unit
off and on may be necessary to cause sequence changes.
• The same staging sequence is used whether a circuit is disabled or not. This means that units
will remain at a stage for an extra stage time when staging up if a disabled circuit is added at
that stage. It also means that units will remain at a stage for an extra stage times when
staging down if a disabled circuit is turned off at that stage.
• Any compressor on the disabled circuit stays off if it is already off and is turned off if it is
on.
McQuay IM 919
41
Cooling: Multistage
Table 27: Standard Staging
Staging
Sequence
Stage 1
Comps
Stage 2
Comps
Stage 3
Comps
Std-1
Std-2
Std-3
Std-4
Std-5
Std-6
Std-7
Std-8
ClgCap
1
2
3
4
5
6
7
8
13%
1,2
1,2
3,4
3,4
5,6
5,6
7,8
7,8
25%
1,2,3
1,2,8
2,3,4
3,4,5
4,5,6
5,6,7
1,7,8
6,7,8
38%
Standard Staging
Stage 4
Stage 5
Comps
Comps
1,2,3,4
1,2,7,8
1,2,3,4
3,4,5,6
3,4,5,6
5,6,7,8
1,2,7,8
5,6,7,8
50%
1,2,3,4,5
1,2,3,7,8
1,2,3,4,8
2,3,4,5,6
3,4,5,6,7
1,5,6,7,8
1,2,6,7,8
4,5,6,7,8
63%
Stage 6
Comps
Stage 7
Comps
Stage 8 Comps
1,2,3,4,5,6
1,2,3,4,7,8
1,2,3,4,7,8
1,2,3,4,5,6
3,4,5,6,7,8
1,2,5,6,7,8
1,2,5,6,7,8
3,4,5,6,7,8
75%
1,2,3,4,5,6,7
1,2,3,4,5,7,8
1,2,3,4,6,7,8
1,2,3,4,5,6,8
1,3,4,5,6,7,8
1,2,3,5,6,7,8
1,2,4,5,6,7,8
2,3,4,5,6,7,8
88%
1,2,3,4,5,6,7,8
1,2,3,4,5,6,7,8
1,2,3,4,5,6,7,8
1,2,3,4,5,6,7,8
1,2,3,4,5,6,7,8
1,2,3,4,5,6,7,8
1,2,3,4,5,6,7,8
1,2,3,4,5,6,7,8
100%
Eight Equal Sized Compressors, Eight Circuits, WRV
Only one sequence is provided so the user makes no selections.
• Total cooling stages = 8.
• Maximum cooling stages is always set to 8.
• If both circuit # 1 and circuit # 2 are enabled, the staging sequence is Std-1 if compressor # 1
has fewer hours than compressor # 2, and the staging sequence is Std-2 if compressor # 1
does not have fewer hours than compressor # 2.
• If Circuit # 1 is disabled, the staging sequence is Std-2.
• If Circuit # 2 is disabled, the staging sequence is Std-1.
• If both circuit # 1 and circuit # 2 are disabled, the staging sequence is Std-1. Only
compressors 3 through 8 are used.
• The Compressor Sequence changes based on Run Time only when the compressor stage
equals Maximum cooling stages or zero. This means that disabling and re-enabling the
compressors or turning the unit off and on may be necessary to cause sequence changes.
• The compressor sequence changes immediately if a circuit is disabled to keep either
compressor # 1 or # 2 on. This will result is compressors being turned off and others being
turned on in this emergency condition.
• The same staging sequence is used whether a circuit is disabled or not. This means that units
will remain at a stage for an extra stage time when staging up if a disabled circuit is added at
that stage. It also means that units will remain at a stage for an extra stage times when
staging down if a disabled circuit is turned off at that stage.
• Any compressor on a disabled circuit stays off if it is already off and is turned off if it is on.
Table 28: Standard Staging
42
Staging
Sequence
Stage 1
Comps
Stage 2
Comps
Stage 3
Comps
Std-1
Std-2
ClgCap
1
2
13%
1,4
2,3
25%
1,4,5
2,3,6
38%
Standard Staging
Stage 4
Stage 5
Comps
Comps
1,4,5,7
2,3,6,8
50%
1,4,5,7,8
2,3,6,7,8
63%
Stage 6
Comps
Stage 7
Comps
Stage 8 Comps
1,4,5,6,7,8 1,2,3,4,5,6,8 1,2,3,4,5,6,7,8
2,3,5,6,7,8 2,3,4,5,6,7,8 1,2,3,4,5,6,7,8
75%
88%
100%
McQuay IM 919
Communication Module
Communication Module
Network Communications
See the Installation & Maintenance Manuals below for detailed instructions
McQuay IM 919
IM 916
MicroTech III Rooftop Unit Controller - BACnet IP Communications
IM 917
MicroTech III Rooftop Unit Controller - BACnet MSTP Communications
IM 918
MicroTech III Rooftop Unit Controller - BACnet LON Communications
43
Software Identification and Configuration
Software Identification and Configuration
After the main control board application software is loaded into the MCB, it must be
“configured” for the specific control application. This consists of setting the value of 23
configuration variables within the MCB. These variables define things such as the type of
cooling, number of compressors and cooling stages and the type of heat. If all of these items
are not set appropriately for the specific unit, the unit will not function properly. The correct
settings for these parameters are defined for a given unit by the unit “Software Configuration
Code”. The code consists of a 26-character string of numbers and letters. The code can be
found on the Unit Software Identification Label located on the back side of the control panel
door. Only the first 23 characters of this code are used for software configuration purposes.
The table shown below lists the configuration code variables including the position within the
code, description of the parameter, and the applicable settings for each. The default values are
shown in bold font. The unit is configured at the factory however may also be configured in
the field by accessing the Unit Configuration Menu. Once changes have been made to the Unit
Configuration Menu, the Apply Changes flag must be changed from no to yes in order for the
controller to recognize the changes. Setting the Apply Changes flag to YES will automatically
cycle power to the controller.
Table 29: Unit Configuration Menu
Configuration
Code Position
Description
Values (Default Bold)
RTU
SCU
1
Unit Type
•
•
2
Control Type
•
•
3
Cooling Type
•
•
4
Compressorized
Cooling
Configuration
•
•
5
Generic Condenser
Stages
Low Ambient
0 = Rooftop (RTU)
1 = Self-Contained (SCU)
0 = Zone Control
1 = DAT Control
0 = None
1 = Compressorized Clg
2 = Chilled Water
3 = F&BP
0 = None
1 = Generic Condenser
2 = 2Cmp/2Circ/3Stg
3 = 3Cmp/2Circ/4Stg
4 = 2Cmp/2Circ/2Stg
5 = 3Cmp/3Circ/3Stg_NoWRV
6 = 3Cmp/3Circ/3Stg_WRV
7 = 4Cmp/2Circ/4Stg
8 = 4Cmp/4Circ/4Stg_NoWRV
9 = 4Cmp/4Circ/4Stg_WRV
A = 6Cmp/2Circ/6Stg
B = 6Cmp/6Circ/6Stg_NoWRV
C = 6Cmp/6Circ/6Stg_WRV
1 – 8 Stages (default = 8)
6
44
7
Evaporative
Condenser Control
8
Damper Type
9
Design Flow
0 = No
1 = Yes
0 = No Evap
1 = Evap _ No VFD
2 = Evap ABB
3 = Evap McQ21
0 = None
1 = Single Position 30%
2 = Single Position 100%
3 = Economizer Airside
4 = Economizer Waterside
0 = No Design Flow
1 = 018-030 (800)
2 = 036-040 (802)
3 = 045-075 (047)
4 = 080-135 (077)
•
•
•
•
•
•
McQuay IM 919
Software Identification and Configuration
Table 29: Unit Configuration Menu
Configuration
Code Position
Description
Values (Default Bold)
RTU
SCU
10
Heating Type
•
•
11
12, 13, 14
15
Max Heating Stages
Max Heat Rise
Supply Fan Type
•
•
•
•
•
•
16
Return Fan Type
17
Return/Exhaust Fan
Capacity Control
Method
18
Second Duct
Pressure Sensor
19
Entering Fan Temp
Sensor
20
Energy Recovery
21
Cooling Circuit Type
22
Head Pressure
Control
23
Bypass Valve Control
24, 25, 26
27
Unit Size
Refrigerant Type
28
HGRH Type
0 = None
1 = F&BP Control
2 = Staged
3 = Modulated Gas, 3-1
4 = Modulated Gas 20-1
5 = Steam or Hot Water
1-8 Stages (Default = 1)
Three Digits (Default = 100)
0=Constant Volume
1=VFD/ABB
2=VFD/Graham
3=VFD/McQ21
4=VFD/McQ31
5=VFD/McQ61
0=CAV
1=RF_EF VFD/ABB
2=RF_EF VFD/Graham
3=RF_EF VFD/McQ21
4=RF_EF VFD/McQ31
5=RF_EF VFD/McQ61
6=PrpEx VFD/ABB
7=PrpEx VFD/Graham
8=PrpEx VFD/McQ21
9=PrpEx VFD/McQ31
A=PrpEx VFD/McQ61
B=None
0 = None
1 = Tracking
2 = Building Pressure
3 = Position
0 = No
1 = Yes
0 = No
1 = Yes
0 = None
1=ConstSpdWhl
2=VarSpdWhl/Grhm
3=VarSpdWhl/McQ21
0 = Individual
1 = Dual Circ. Water Condenser
2 = Dual Circ. Air Condenser
0 = No
1 = Yes
0 = Slave
1 = Bypass
Three digits (default 050)
0 = R22
1 = R407C
2 = R410A
0 = None
1 = Staged
2 = Modulating
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Max Heat Rise represents positions 12, 13 and 14 of the software configuration string.
McQuay IM 919
45
Typical Electrical Drawings - Rooftop
Typical Electrical Drawings - Rooftop
Figure 29: VAV Power
46
McQuay IM 919
Typical Electrical Drawings - Rooftop
Figure 30: VAV Power (Continued)
McQuay IM 919
47
Typical Electrical Drawings - Rooftop
Figure 31: Controller Inputs
48
McQuay IM 919
Typical Electrical Drawings - Rooftop
Figure 32: Controller Inputs (Continued)
McQuay IM 919
49
Typical Electrical Drawings - Rooftop
Figure 33: Controller Inputs/Outputs
50
McQuay IM 919
Typical Electrical Drawings - Rooftop
Figure 34: Controller Inputs/Outputs (Continued)
McQuay IM 919
51
Typical Electrical Drawings - Rooftop
Figure 35: VFD Power
52
McQuay IM 919
Typical Electrical Drawings - Rooftop
Figure 36: Condenser Section Power
McQuay IM 919
53
Typical Electrical Drawings - Rooftop
Figure 37: Condenser Section Control
54
McQuay IM 919
Typical Electrical Drawings - Rooftop
Figure 38: Condenser Section Control (Continued)
McQuay IM 919
55
Typical Electrical Drawings - Self Contained
Typical Electrical Drawings - Self Contained
Figure 39: VAV Power
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Typical Electrical Drawings - Self Contained
Figure 40: VAV Power (Continued)
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Typical Electrical Drawings - Self Contained
Figure 41: Controller Inputs
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Typical Electrical Drawings - Self Contained
Figure 42: Controller Inputs/Outputs
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Typical Electrical Drawings - Self Contained
Figure 43: VFD Control
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Typical Electrical Drawings - Self Contained
Figure 44: VFD Control (Continued)
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Typical Electrical Drawings - Self Contained
Figure 45: Condensing Section Control
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Typical Electrical Drawings - Self Contained
Figure 46: Condensing Section Control (Continued)
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Parts List
Parts List
64
McQuay Part
Number
Component
Designation
Description
MCB
Main Control Board - MTIII
193407301
EXP A, B, C
Expansion Module
193407501
ZNT1
Zone Temperature Sensor with Tenant Override
113117701
ZNT1
Zone Temperature Sensor with Tenant Override & Remote
set point adjustment
113117801
DAT
Discharge Air Temperature Sensor
193414600
EFT
Entering Fan Air Temperature Sensor
193414600
OAT
Outside Air Temperature Sensor
193414600
RAT
Return Air Temperature Sensor
193414600
MAT
Mixed Air Temperature Sensor
193414600
EWT
Entering Water Temperature Sensor
193414600
ER DAT
Energy Recovery Wheel Discharge Air Temperature Sensor
193414600
ER Exh T
Energy Recovery Wheel Exhaust Air Temperature Sensor
193414600
SPS1, 2
Duct Static Pressure Sensor
049545013
SPS3
Building Static Pressure Sensor
049545012
PSR1
Refrigerant Pressure Transducer Circuit 1
065816802
PSR2
Refrigerant Pressure Transducer Circuit 2
065816802
T2
Transformer 115/24 VAC
349937303
T3
Transformer 115/24 VAC
349937303
T9
Transformer 115/24 VAC
N/A
SHS1
Space Humidity Sensor, Wall Mount
067294901
SHS1
Space Humidity Sensor, Duct Mount
067295001
WFS
Water Flow Switch
098867101
PC5
Dirty filter switch: prefilter
065493801
PC6
Dirty filter switch: final filter
065493801
PC7
Airflow proving switch
060015801
DHL
Duct High Limit
065493801
OAE
Enthalpy Control, Electro-Mechanical
030706702
OAE
Enthalpy Control, Comparative
049262201
RAE
Return Air Enthalpy Sensor
049262202
SD1
Smoke Detector: Supply Air
098873101
SD2
Smoke Detector: Return Air
098873101
-
Communication Module - LON
193408201
-
Communication Module - BACnet MSTP
193408301
-
Communication Module - BACnet IP
193408401
-
Controller Terminal Block - 2 pole
193410402
-
Controller Terminal Block - 3 pole
193410403
Controller Terminal Block - 5 pole
193410405
Controller Terminal Block - 6 pole
193410406
Controller Terminal Block - 7 pole
193410407
Controller Terminal Block - 8 pole
193410408
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McQuay Training and Development
Now that you have made an investment in modern, efficient McQuay equipment, its care should be a high priority.
For training information on all McQuay HVAC products, please visit us at www.mcquay.com and click on training, or
call 540-248-9646 and ask for the Training Department.
Warranty
All McQuay equipment is sold pursuant to its standard terms and conditions of sale, including Limited Product
Warranty. Consult your local McQuay Representative for warranty details. Refer to Form 933-43285Y. To find your
local McQuay Representative, go to www.mcquay.com.
This document contains the most current product information as of this printing. For the most up-to-date product
information, please go to www.mcquay.com.
© 2008 McQuay International • www.mcquay.com • 800-432-1342