AAON MODGAS-XWR2 Quick start guide

MODGAS-XWR2 Module
Technical Guide

2MODGAS-XWR2 Technical Guide
AAON
2425 South Yukon Ave.
Tulsa, OK 74107-2728
www.aaon.com
Factory Technical Support Phone: [phone]
AAON Controls Support: 866-918-1100
It is the intent of AAON to provide accurate and current product
information. However, in the interest of product improvement,
AAON reserves the right to change pricing, specications, and/
or design of its product without notice, obligation, or liability.
AAON P/N: V22330, Rev. D
© November 2021 AAON Inc. All rights reserved.
AAON®is a registered trademark of AAON, Inc., Tulsa, OK.
White-Rogers®is a registered trademark of Emerson Climate
Technologies, Inc., St. Louis, MO
AAON assumes no responsibility for errors or omissions in
this document.
This document is subject to change without notice.
www.aaon.com
MODGAS-XWR2 PARTS REFERENCE
PART DESCRIPTION PART NUMBER
MODGAS-XWR2 Module ASM01695
12 Relay E-BUS Expansion Module ASM01873
VCCX2 Controller ASM01698
MHGRV-X Module ASM01670
Supply Air Temperature Sensor (6 in and 12 in.) G051240 (6 in.) and G051250 (12 in.)
All manuals are also available for download from
www.aaon.com/controlsmanuals.
MODGAS-XWR2 REVISION LOG
REVISION AND DATE
Rev. 01C, January 2020 Previous revision
Rev. D, November 01, 2021 Updated part numbers and labels. Added Figure/Table content pages, and
Fahrenheit/Celsius temperature conversion. Corrected cosmetic errors.

3
MODGAS-XWR2 Technical Guide
OVERVIEW....................................................................................................................... 5
General Information ................................................................................................................................................ 5
Dimensions ............................................................................................................................................................. 6
WIRING ............................................................................................................................ 7
Important Wiring Considerations............................................................................................................................. 7
STAND-ALONE WIRING .................................................................................................. 8
One Modulating Valve, One Ignitor, One Stage (1V1IGN1S) ................................................................................. 8
Two Modulating Valves, Two Ignitors, Two Stages (2V2IGN2S)............................................................................. 9
Two Modulating Valves, One Ignitor, One Stage (2V1IGN1S)...............................................................................11
Two Modulating Valves, Two Ignitors, One Stage (2V2IGN1S) ............................................................................ 13
12 Relay E-BUS Expansion Module ..................................................................................................................... 14
COMMUNICATIONS WIRING ........................................................................................ 15
One Modulating Valve, One Ignitor, One Stage (1V1IGN1S) ............................................................................... 15
Two Modulating Valves, Two Ignitors, One Stage (2V2IGN1S) ............................................................................ 16
Two Modulating Valves, Two Ignitors, Two Stages (2V2IGN2S)........................................................................... 17
Two Modulating Valves, One Ignitor, One Stage (2V1IGN1S).............................................................................. 19
INPUTS AND OUTPUTS................................................................................................ 21
Inputs and Outputs................................................................................................................................................ 21
SEQUENCE OF OPERATION......................................................................................... 23
Operating Modes and Min Mode........................................................................................................................... 23
Heating Mode........................................................................................................................................................ 24
Valve Failure, Force Mode and Master vs. Normal............................................................................................... 25
LCD SCREENS ............................................................................................................... 26
Navigation Keys .................................................................................................................................................... 26
Main Screens Map ................................................................................................................................................ 27
Main Screens ........................................................................................................................................................ 28
Alarms Menu and Slave Alarms............................................................................................................................ 30
Setpoint Screens................................................................................................................................................... 31
Force Valves Screens ........................................................................................................................................... 32
Protected and Conguration Screens ................................................................................................................... 33
Conguration Screens .......................................................................................................................................... 34
TROUBLESHOOTING .................................................................................................... 35
LED Diagnostics ................................................................................................................................................... 35
Alarms................................................................................................................................................................... 37
SAT Sensor Testing............................................................................................................................................... 38
APPENDIX A: SAT SENSOR.......................................................................................... 40
Installation............................................................................................................................................................. 40
SAT Sensor Wiring Guide and Jumper Settings ................................................................................................... 41
APPENDIX B: MODGAS-XWR REPLACEMENT ............................................................ 42
MODGAS-XWR2 Replacement of MODGAS-XWR.............................................................................................. 42
TABLE OF CONTENTS

4MODGAS-XWR2 Technical Guide
FIGURES AND TABLES
TABLES
Table 1: Electrical and Environmental Requirements .........................................................................................................7
Table 2: MODGAS-XWR2 Inputs and Outputs ..................................................................................................................21
Table 3: Navigation Key Functions.......................................................................................................................................26
Table 4: Editing Key Functions .............................................................................................................................................26
Table 5: STATUS LED Blink Codes .....................................................................................................................................35
Table 6: ALARM LED Blink Codes.......................................................................................................................................35
Table 7: 0-3V Temperature Sensor - Voltage and Resistance for Type III Sensors.....................................................38
Table 8: 0-5V Temperature Sensor - Voltage and Resistance for Type III Sensors.....................................................39
Table 9: SAT Wiring Conditions ............................................................................................................................................41
Table 10: Stand-Alone Mode SAT OPTIONS Jumper Settings .........................................................................................41
Table 11: Communication Mode SAT OPTIONS Jumper Settings ...................................................................................41
FIGURES
Figure 1: MODGAS-XWR2 Module Dimensions ...................................................................................................................6
Figure 2: Stand-Alone Wiring - One Modulating Valve, One Ignitor, One Stage..............................................................8
Figure 3: Stand-Alone Wiring - Two Modulating Valves, Two Ignitors, Two Stages ........................................................9
Figure 4: Stand-Alone Wiring - Secondary Board 2V2IGN2S...........................................................................................10
Figure 5: Stand-Alone Wiring - Two Modulating Valves, One Ignitor, One Stage .......................................................... 11
Figure 6: Stand-Alone Wiring - Secondary Board 2V1IGN1S...........................................................................................12
Figure 7: Stand-Alone Wiring - Two Modulating Valves, Two Ignitors, One Stage ........................................................13
Figure 8: Stand-Alone Wiring - 12 Relay E-BUS Expansion Module...............................................................................14
Figure 9: Communications Wiring - One Modulating Valve, One Ignitor, One Stage ....................................................15
Figure 10: Communications Wiring - One Modulating Valve, Two Ignitors, One Stage ..................................................16
Figure 11: Communications Wiring - Two Modulating Valves, Two Ignitors, Two Stages...............................................17
Figure 12: Communications Wiring - Secondary Board 2V2IGN2S ...................................................................................18
Figure 13: Communications Wiring - Two Modulating Valves, One Ignitor, One Stage ..................................................19
Figure 14: Stand-Alone Wiring - Secondary Board 2V1IGN1S...........................................................................................20
Figure 15: LCD Display and Navigation Keys........................................................................................................................26
Figure 16: MODGAS-XWR2 LED Locations and Descriptions ...........................................................................................36
Figure 17: Supply Air Temperature Sensor Installation ........................................................................................................40
Figure 18: MODGAS-XWR2 Module .......................................................................................................................................42

5
MODGAS-XWR2 Technical Guide
OVERVIEW
General Information
Overview
The MODGAS-XWR2 Module (previously referred to as the
MODGAS-XWR-1) is designed to be used with White-Rogers®
valves only. It will modulate up to two White-Rogers®gas
valves to maintain a desired Supply Air Temperature (up to
four modulating gas valves may be controlled when a second
MODGAS-XWR2 is configured as a slave module). The
MODGAS-XWR2 also controls the speed of the induction motors
in combustion air blowers. See Figure 1, page 6.
NOTE: The MODGAS-XWR2 provides two more relays
than the MODGAS-XWR and can replace the
MODGAS-XWR. See page 42 for replacement
instructions.
The MODGAS-XWR2 can be used in Stand-Alone Mode
or connected to a VCCX2 Controller, VCB-X Controller, or
VCM-X E-BUS (I2C) Controller using a modular or E-BUS
cable, depending on the type of controller used.
The MODGAS-XWR2 can have the following congurations:
• One modulating valve with one ignitor as one stage.
• Two modulating valves with one ignitor as one stage.
• Two modulating valves with two ignitors as one stage.
• Two modulating valves, with two ignitors as two stages.
Two MODGAS-XWR2 Modules (Primary/Secondary) may be
congured to control four modulating valves as one stage - two
valves with one ignitor on each board. In addition, two modules
may be congured to control four modulating valves with two
ignitors on each board. The rst valve on each board is stage one
and the second valve on each board is stage two.
NOTE: Primary/Secondary conguration is not supported
using I2C communications (VCM-X E-BUS).
The MODGAS-XWR2 can also control or eect control of
additional xed valves for additional stages of heat by using the
additional heat relays on the board itself. When the MODGAS-
XWR2 is attached to one of the listed AAON unit controllers,
these additional stages are aected through the AAON unit
controller. In Stand-Alone Mode, these additional xed heat
stages can be increased by attaching a 12 Relay E-BUS Expansion
Module. In Communications Mode, additional xed heat stages
can be increased by attaching a 12 Relay E-BUS Expansion
Module to the AAON unit controller.
Features
The MODGAS-XWR2 provides the following:
• Can control two gas valves using input from Proof of
Ignition Modules.
• A second MODGAS-XWR2 can be added to allow
control of four modulating gas valves.
• Monitors Supply Air Temperature and Supply Air Reset
and modulates gas valves to maintain the Supply Air
Temperature and Supply Air Reset Setpoints.
• Provides active relays to control the Fan, Fan Speed,
and Heat Stages.
• Controls up to four stages of Heat with one module.
• Contains a 2 x 8 LCD character display and four buttons
that allow for status display, setpoint changes, and
conguration changes.
NOTE: The MODGAS-XWR2 contains no user
serviceable parts. Contact qualified technical
personnel if your MODGAS-XWR2 is not
operating correctly.

6MODGAS-XWR2 Technical Guide
OVERVIEW
Dimensions
5.8
2.62
2.04
4.10
0.58
5.05 5.64
0.25
Note: Depth is 1.49 inches.
Note: All dimensions are in inches.
ASSEMBLED IN USA
U15
D13
R
R
R
R
L1
R61 C28
SERIAL #
POWER
COMM
ALARM
STATUS
TB3
GND
AUX AIN
J3
GND
1
2
SAT
OPTIONS
RESET IN
D8
HEAT EN
D7
AUX BIN
GND
J1 U1
TB2
R1
YS102408 REV 3
TB1
RLY1
RLY2
RLY3
RLY4
RLY5
RLY6
COMMON
PO-IGN1
P3
D9
R33
R1
P1
PO-IGN2
P4
D10
R36
R2
Q2
R5
P2
C35
.01UF
R8
R22
R18
R16
R12
R13
R42
R44
D14
SOFTWARE
C22
C27
GAS VALVE 2
GAS VALVE 1
ALARM
UP
DOWN
ENTERMENU
MODGAS-XWR2
AAON P/N:ASM01695
LABEL P/N:
G041530 E-BUS
DUAL
I2C
CONNECT
+24 VAC
GND
@ 24 VAC
1 AMP MAX
CONTACT
RATING IS
COMMON
RELAY
OUTPUTS
GAS VALVE
TERMINALS
GAS
VALVE 1
GAS
VALVE 2
INPUT TERMINALS (TYPE)
HEAT ENABLE (BI)
AUX. (BI)
GND
RESET IN (AI)
SAT IN (AI)
GND (AI)
GND
AUX. (AI)
www.aaon.com
LOW SPEED
HEAT 1
HEAT 2
HEAT 3
HEAT 4
PROOF OF IGNITION 1
PROOF OF IGNITION 2
FAN
Figure 1: MODGAS-XWR2 Module Dimensions

7
MODGAS-XWR2 Technical Guide
WIRING
Important Wiring Considerations
Wiring
The modules must be connected to an 18-30 VAC power source
of the proper size for the calculated VA load requirements. All
transformer sizing should be based on the VA ratings listed in
Table 1, this page.
NOTE: If the temperature at the MODGAS-XWR2 is
below -4ºF (-20ºC), the display refresh rate could
be less responsive.
WARNING: When using a single transformer to power
more than one controller or expansion
module, the correct polarity must always
be maintained between the boards. Failure
to observe correct polarity will result in
damage to the AAON unit controller,
MODGAS-XWR2, and any associated
module.
Please carefully read and apply the following information when
wiring the AAON unit controller, MODGAS-XWR2 and any
associated module.
1. All wiring is to be in accordance with local and
national electrical codes and specications.
2. All 24 VAC wiring must be connected so that all
ground wires remain common. Failure to follow this
procedure can result in damage to the controller and
connected devices.
3. Minimum wire size for 24 VAC wiring should be
18-gauge.
4. Minimum wire size for all sensors should be 24-gauge.
Some sensors require two-conductor wire and some
require three-or four-conductor wire.
5. Minimum wire size for 24 VAC thermostat wiring
should be 22-gauge.
6. Be sure that all wiring connections are properly
inserted and tightened into the terminal blocks. Do
not allow wire strands to stick out and touch adjoining
terminals which could potentially cause a short circuit.
7. When communication wiring is to be used to
interconnect AAON unit controllers together or to
connect to other communication devices, all wiring
must be plenum-rated, minimum 18-gauge, two-
conductor, twisted-pair with shield. AAON can supply
communication wire that meets this specication and
is color coded for the network or local loop. Please
consult your AAON distributor for information. If
desired, Belden #82760 or equivalent wire may also
be used.
8. Before applying power to the AAON unit controller,
MODGAS-XWR2, and any associated modules,
be sure to recheck all wiring connections and
terminations thoroughly.
Powering Up
When the controller and modules are rst powered up, the
POWER LED should light up and stay on continuously. If it does
not light up, check to be sure that you have 24 VAC connected
to the controller, that the wiring connections are tight, and that
they are wired for the correct polarity. The 24 VAC power must
be connected so that all ground wires remain common. If after
making all these checks, the POWER LED does not light up,
please contact AAON Controls Support for assistance.
Control
Device
Voltage
VA Load
Operating
Temperature
Humidity
(Non-
Condensing)
MODGAS-XWR2
18-30 VAC 18 -22°F to 158°F
-30ºC to 70ºC 0-95% RH
Inputs
Resistive Inputs require 10KΩ
Type III Thermistor
24 VAC Inputs provide 4.7KΩ
Load
Outputs Relay Outputs: 1 amp
maximum per output.
Table 1: Electrical and Environmental Requirements

8MODGAS-XWR2 Technical Guide
STAND-ALONE WIRING
One Modulating Valve, One Ignitor, One Stage (1V1IGN1S)
This conguration is used to control one modulating valve, which
must be placed on Gas Valve 1 (attached to Heat 1 (RLY3)).
If using an MHGRV-X along with the MODGAS-XWR2 in
Stand-Alone Mode, the SAT Sensor always attaches to the
MODGAS-XWR2.
Fan Enable
Low Speed Fan
Connect SAT Input
to Reheat Board’s SAT
Input if applicable.
Modulating
Gas Valve 1
Proof of Ignition
Signal 1 (24 VAC)
Heat Valve 1
-
0-10VDC
External
Reset Signal
Check your Fan Relay Wiring (RLY1)
Schematic for proper wiring.
Fixed Heat Stage 2
Fixed Heat Stage 3
Fixed Heat Stage 4
ALARM
UP
DOWN
ENTERMENU
MODGAS-XWR2
AAON P/N:ASM01695
LABEL P/N:
G041530 E-BUS
DUAL
I2C
CONNECT
+24 VAC
GND
@ 24 VAC
1 AMP MAX
CONTACT
RATING IS
COMMON
RELAY
OUTPUTS
GAS VALVE
TERMINALS
GAS
VALVE 1
GAS
VALVE 2
INPUT TERMINALS (TYPE)
HEAT ENABLE (BI)
AUX. (BI)
GND
RESET IN (AI)
SAT IN (AI)
GND (AI)
GND
AUX. (AI)
www.aaon.com
LOW SPEED
HEAT 1
HEAT 2
HEAT 3
HEAT 4
PROOF OF IGNITION 1
PROOF OF IGNITION 2
FAN
See SAT OPTIONS Tables for Jumper Settings.
Only one Supply Air Temperature Sensor can be
used per application.
Notes:
1. 24 VAC must be connected so that all ground wires
remain common.
2. All wiring to be in accordance with local and national
electrical codes and specifications. E-BUS cable can connect to
12 Relay E-BUS Expansion Port
GV1
CR1
CR2
H1
Line
40 VA
transformer
minimum
Supply Air
Temperature
Sensor
Mount in unit
supply air duct
Heat Enable
Signal (24 VAC)
W1
GND 18-30
VAC
Figure 2: Stand-Alone Wiring - One Modulating Valve, One Ignitor, One Stage
NOTE: Up to three additional xed heat stages can be
configured by using Heat 2 (RLY4), Heat 3
(RLY5) and Heat 4 (RLY6). Up to 12 additional
xed stages can be added by using the 12 Relay
E-BUS Expansion Module. (Figure 8, page 14).

9
MODGAS-XWR2 Technical Guide
STAND-ALONE WIRING
Two Modulating Valves, Two Ignitors, Two Stages (2V2IGN2S)
This conguration is used to control two modulating gas valves.
The rst valve is modulating stage 1 (Gas Valve 1) and the
second valve is modulating stage 2 (Gas Valve 2).The rst valve
is attached to Heat 1 (RLY3) and the second valve is attached
to Heat 2 (RLY4).
If using an MHGRV-X along with the MODGAS-XWR2 in
Stand-Alone Mode, the SAT Sensor always attaches to the
MODGAS-XWR2.
Figure 3: Stand-Alone Wiring - Two Modulating Valves, Two Ignitors, Two Stages
NOTE: Up to two additional xed heat stages can be
congured by using Heat 3 (RLY5) and Heat 4
(RLY6). Up to 12 additional xed stages can be
added by using the 12 Relay E-BUS Expansion
Module. (Figure 8, page 14).
Fan Enable
Low Speed Fan
Connect SAT Input
to Reheat Board’s SAT
Input if applicable.
Modulating
Gas Valve 1
Proof of Ignition
Signal 1 (24 VAC)
Heat Valve 1
-
0-10VDC
External
Reset Signal
Check your Fan Relay Wiring (RLY1)
Schematic for proper wiring.
Heat Valve 2
Fixed Heat Stage 3
Fixed Heat Stage 4
ALARM
UP
DOWN
ENTERMENU
MODGAS-XWR2
AAON P/N:ASM01695
LABEL P/N:
G041530 E-BUS
DUAL
I2C
CONNECT
+24 VAC
GND
@ 24 VAC
1 AMP MAX
CONTACT
RATING IS
COMMON
RELAY
OUTPUTS
GAS VALVE
TERMINALS
GAS
VALVE 1
GAS
VALVE 2
INPUT TERMINALS (TYPE)
HEAT ENABLE (BI)
AUX. (BI)
GND
RESET IN (AI)
SAT IN (AI)
GND (AI)
GND
AUX. (AI)
www.aaon.com
LOW SPEED
HEAT 1
HEAT 2
HEAT 3
HEAT 4
PROOF OF IGNITION 1
PROOF OF IGNITION 2
FAN
See SAT OPTIONS Tables for Jumper Settings.
Only one Supply Air Temperature Sensor can be
used per application.
Notes:
1. 24 VAC must be connected so that all ground wires
remain common.
2. All wiring to be in accordance with local and national
electrical codes and specifications.
E-BUS cable can connect to a
secondary MODGAS-XWR2 or to a
12 Relay E-BUS expansion port
GV1
CR1
CR2
H1
Line
40 VA
transformer
minimum
Supply Air
Temperature
Sensor
Mount in unit
supply air duct
Heat Enable
Signal (24 VAC)
W1
GND 18-30
VAC
H2
Modulating
Gas Valve 2
Proof of Ignition
Signal 2 (24 VAC)
GV2

10 MODGAS-XWR2 Technical Guide
STAND-ALONE WIRING
Secondary Board 2V2IGN2S
In this conguration, the wiring on Figure 3, page 9 is the
primary portion and Figure 4, this page is the secondary portion,
creating four modulating valves as two stages.
If using an MHGRV-X Module along with the secondary
MODGAS-XWR2 in Stand-Alone Mode, the SAT Sensor always
attaches to the Primary MODGAS-XWR2.
Figure 4: Stand-Alone Wiring - Secondary Board 2V2IGN2S
Fan Enable
Low Speed Fan
Modulating
Gas Valve 3
(Slave to Mod
Gas Valve 1)
Proof of Ignition
Signal 3 (24 VAC)
Heat Valve 1
Check your Fan Relay Wiring (RLY1)
Schematic for proper wiring.
Heat Valve 2
Fixed Heat Stage 5
Fixed Heat Stage 6
ALARM
UP
DOWN
ENTERMENU
MODGAS-XWR2
AAON P/N:ASM01695
LABEL P/N:
G041530 E-BUS
DUAL
I2C
CONNECT
+24 VAC
GND
@ 24 VAC
1 AMP MAX
CONTACT
RATING IS
COMMON
RELAY
OUTPUTS
GAS VALVE
TERMINALS
GAS
VALVE 1
GAS
VALVE 2
INPUT TERMINALS (TYPE)
HEAT ENABLE (BI)
AUX. (BI)
GND
RESET IN (AI)
SAT IN (AI)
GND (AI)
GND
AUX. (AI)
www.aaon.com
LOW SPEED
HEAT 1
HEAT 2
HEAT 3
HEAT 4
PROOF OF IGNITION 1
PROOF OF IGNITION 2
FAN
Notes:
1. 24 VAC must be connected so that all ground wires
remain common.
2. All wiring to be in accordance with local and national
electrical codes and specifications.
E-BUS cable connects to the
primary MODGAS-XWR2.
GV3
CR3
CR4
H1
Line
40 VA
transformer
minimum
GND 18-30
VAC
H2
Proof of Ignition
Signal 4 (24 VAC)
GV4
Modulating
Gas Valve 4
(Slave to Mod
Gas Valve 2)
NOTE: Up to two additional xed heat stages can be
congured by using Heat 3 (RLY5) and Heat 4
(RLY6). Up to 12 additional xed stages can be
added by using the 12 Relay E-BUS Expansion
Module. (Figure 8, page 14).

11
MODGAS-XWR2 Technical Guide
STAND-ALONE WIRING
Two Modulating Valves, One Ignitor, One Stage (2V1IGN1S)
Figure 5: Stand-Alone Wiring - Two Modulating Valves, One Ignitor, One Stage
This conguration is used to control two modulating gas valves
(one on each terminal connector), in which the rst and second
valves operate together for one modulating stage. Both valves
are connected to Heat 1 (RLY3).
If using an MHGRV-X Module along with the secondary
MODGAS-XWR2 in Stand-Alone Mode, the SAT Sensor always
attaches to the primary MODGAS-XWR2.
Fan Enable
Low Speed Fan
Connect SAT Input
to Reheat Board’s SAT
Input if applicable.
Modulating
Gas Valve 1
Proof of Ignition
Signal 1 (24 VAC)
Heat Valve 1
-
0-10VDC
External
Reset Signal
Check your Fan Relay Wiring (RLY1)
Schematic for proper wiring.
ALARM
UP
DOWN
ENTERMENU
MODGAS-XWR2
AAON P/N:ASM01695
LABEL P/N:
G041530 E-BUS
DUAL
I2C
CONNECT
+24 VAC
GND
@ 24 VAC
1 AMP MAX
CONTACT
RATING IS
COMMON
RELAY
OUTPUTS
GAS VALVE
TERMINALS
GAS
VALVE 1
GAS
VALVE 2
INPUT TERMINALS (TYPE)
HEAT ENABLE (BI)
AUX. (BI)
GND
RESET IN (AI)
SAT IN (AI)
GND (AI)
GND
AUX. (AI)
www.aaon.com
LOW SPEED
HEAT 1
HEAT 2
HEAT 3
HEAT 4
PROOF OF IGNITION 1
PROOF OF IGNITION 2
FAN
See SAT OPTIONS Tables for Jumper Settings.
Only one Supply Air Temperature Sensor can be
used per application.
Notes:
1. 24 VAC must be connected so that all ground wires
remain common.
2. All wiring to be in accordance with local and national
electrical codes and specifications. E-BUS cable can connect to a
secondary MODGAS-XWR2 or to
a 12 Relay E-BUS expansion port
GV1
CR1
CR2
H1
Line
40 VA
transformer
minimum
Supply Air
Temperature
Sensor
Mount in unit
supply air duct
Heat Enable
Signal (24 VAC)
W1
GND 18-30
VAC
Modulating
Gas Valve 2
GV2
Fixed Heat Stage 2
Fixed Heat Stage 3
Fixed Heat Stage 4
NOTE: Up to three additional xed heat stages can be
configured by using Heat 2 (RLY4), Heat 3
(RLY5) and Heat 4 (RLY6). Up to 12 additional
xed stages can be added by using the 12 Relay
E-BUS Expansion Module. (Figure 8, page 14).

12 MODGAS-XWR2 Technical Guide
STAND-ALONE WIRING
Secondary Board - 2V1IGN1S
In this conguration, the wiring on Figure 5, page 11 is the
primary portion and Figure 6, this page is the secondary portion,
creating four modulating valves as one stage.
If using an MHGRV-X Module along with the secondary
MODGAS-XWR2 in Stand-Alone Mode, the SAT Sensor always
attaches to the Primary MODGAS-XWR2.
Figure 6: Stand-Alone Wiring - Secondary Board 2V1IGN1S
Fan Enable
Low Speed Fan
Proof of Ignition
Signal 2 (24 VAC)
Heat Valve 2
Check your Fan Relay Wiring (RLY1)
Schematic for proper wiring.
ASSEMBLED IN USA
U15
D13
R
R
R
R
L1
R61 C28
SERIAL #
POWER
COMM
ALARM
STATUS
TB3
GND
AUX AIN
J3
GND
1
2
SAT
OPTIONS
RESET IN
D8
HEAT EN
D7
AUX BIN
GND
J1 U1
TB2
R1
YS102408 REV 3
TB1
RLY1
RLY2
RLY3
RLY4
RLY5
RLY6
COMMON
PO-IGN1
P3
D9
R33
R1
P1
PO-IGN2
P4
D10
R36
R2
Q2
R5
P2
C35
.01UF
R8
R22
R18
R16
R12
R13
R42
R44
D14
SOFTWARE
C22
C27
GAS VALVE 2
GAS VALVE 1
ALARM
UP
DOWN
ENTERMENU
MODGAS-XWR2
AAON P/N:ASM01695
LABEL P/N:
G041530 E-BUS
DUAL
I2C
CONNECT
+24 VAC
GND
@ 24 VAC
1 AMP MAX
CONTACT
RATING IS
COMMON
RELAY
OUTPUTS
GAS VALVE
TERMINALS
GAS
VALVE 1
GAS
VALVE 2
INPUT TERMINALS (TYPE)
HEAT ENABLE (BI)
AUX. (BI)
GND
RESET IN (AI)
SAT IN (AI)
GND (AI)
GND
AUX. (AI)
www.aaon.com
LOW SPEED
HEAT 1
HEAT 2
HEAT 3
HEAT 4
PROOF OF IGNITION 1
PROOF OF IGNITION 2
FAN
Notes:
1. 24 VAC must be connected so that all ground wires
remain common.
2. All wiring to be in accordance with local and national
electrical codes and specifications.
E-BUS cable connects to the
primary MODGAS-XWR2.
GV3
CR3
CR4
H1
Line
40 VA
transformer
minimum
GND 18-30
VAC
GV4
Fixed Heat Stage 5
Fixed Heat Stage 6
Fixed Heat Stage 7
Modulating
Gas Valve 3
Modulating
Gas Valve 4
NOTE: Up to three additional xed heat stages can be
configured by using Heat 2 (RLY4), Heat 3
(RLY5) and Heat 4 (RLY6). Up to 12 additional
xed stages can be added by using the 12 Relay
E-BUS Expansion Module. (Figure 8, page 14).

13
MODGAS-XWR2 Technical Guide
STAND-ALONE WIRING
Two Modulating Valves, Two Ignitors, One Stage (2V2IGN1S)
Figure 7: Stand-Alone Wiring - Two Modulating Valves, Two Ignitors, One Stage
Fan Enable
Low Speed Fan
Connect SAT Input
to Reheat Board’s SAT
Input if applicable.
Modulating
Gas Valve 1
(Modulates with
Valve 2 as 1 Stage
Proof of Ignition
Signal 1 (24 VAC)
Heat Valve 1
-
0-10VDC
External
Reset Signal
Check your Fan Relay Wiring (RLY1)
Schematic for proper wiring.
Heat Valve 2
Fixed Heat Stage 3
Fixed Heat Stage 4
ASSEMBLED IN USA
U15
D13
R
R
R
R
L1
R61 C28
SERIAL #
POWER
COMM
ALARM
STATUS
TB3
GND
AUX AIN
J3
GND
1
2
SAT
OPTIONS
RESET IN
D8
HEAT EN
D7
AUX BIN
GND
J1 U1
TB2
R1
YS102408 REV 3
TB1
RLY1
RLY2
RLY3
RLY4
RLY5
RLY6
COMMON
PO-IGN1
P3
D9
R33
R1
P1
PO-IGN2
P4
D10
R36
R2
Q2
R5
P2
C35
.01UF
R8
R22
R18
R16
R12
R13
R42
R44
D14
SOFTWARE
C22
C27
GAS VALVE 2
GAS VALVE 1
ALARM
UP
DOWN
ENTERMENU
MODGAS-XWR2
AAON P/N:ASM01695
LABEL P/N:
G041530 E-BUS
DUAL
I2C
CONNECT
+24 VAC
GND
@ 24 VAC
1 AMP MAX
CONTACT
RATING IS
COMMON
RELAY
OUTPUTS
GAS VALVE
TERMINALS
GAS
VALVE 1
GAS
VALVE 2
INPUT TERMINALS (TYPE)
HEAT ENABLE (BI)
AUX. (BI)
GND
RESET IN (AI)
SAT IN (AI)
GND (AI)
GND
AUX. (AI)
www.aaon.com
LOW SPEED
HEAT 1
HEAT 2
HEAT 3
HEAT 4
PROOF OF IGNITION 1
PROOF OF IGNITION 2
FAN
See SAT OPTIONS Tables for Jumper Settings.
Only one Supply Air Temperature Sensor can be
used per application.
Notes:
1. 24 VAC must be connected so that all ground wires
remain common.
2. All wiring to be in accordance with local and national
electrical codes and specifications. E-BUS cable can connect to a
secondary MODGAS-XWR2 or to
12 Relay E-BUS expansion port
GV1
CR1
CR2
H1
Line
40 VA
transformer
minimum
Supply Air
Temperature
Sensor
Mount in unit
supply air duct
Heat Enable
Signal (24 VAC)
W1
GND 18-30
VAC
H2
Proof of Ignition
Signal 2 (24 VAC)
GV2
Modulating
Gas Valve 2
(Modulates with
Valve 1 as 1 Stage
This conguration is used to control two modulating gas valves
(one on each terminal connector), in which the rst and second
valves operate together for one modulating stage. One valve is
connected to Heat 1 (RLY3) and the second valve is connected
to Heat 2 (RLY4).
If using an MHGRV-X Module along with the secondary
MODGAS-XWR2 in Stand-Alone Mode, the SAT Sensor always
attaches to the Primary MODGAS-XWR2.
NOTE: Up to two additional xed heat stages can be
congured by using Heat 3 (RLY5) and Heat 4
(RLY6). Up to 12 additional xed stages can be
added by using the 12 Relay E-BUS Expansion
Module. (Figure 8, page 14).

14 MODGAS-XWR2 Technical Guide
STAND-ALONE WIRING
12 Relay E-BUS Expansion Module
Figure 8: Stand-Alone Wiring - 12 Relay E-BUS Expansion Module
WARNING: Observe Polarity. All boards must be wired
with GND-to-GND and 24 VAC-to-24
VAC. Failure to observe polarity will result
in damage to one or more of the boards.
Expansion modules must be wired in such
a way that the expansion modules and the
controller are always powered together. Loss
of power to the expansion module will cause
the controller to become inoperative until
power is restored to the expansion module.
Note: n = Number of fixed heat stages
configured on MODGAS-XWR2.
Fixed Heat Stage n + 1
18-30 VAC
GND
18-30
VAC
GND
15 VA minimum
power required
E-BUS cable connects to a
MODGAS-XWR2 or E-BUS
Adapter Hub
Fixed Heat Stage n + 2
Fixed Heat Stage n + 3
Fixed Heat Stage n + 4
Fixed Heat Stage n + 5
Fixed Heat Stage n + 6
Fixed Heat Stage n + 7
Fixed Heat Stage n + 8
Fixed Heat Stage n + 9
Fixed Heat Stage n + 10
Fixed Heat Stage n + 11
Fixed Heat Stage n + 12
Note: All relay outputs are normally open
and rated for 24 VAC power only.
1 amp maximum load.

15
MODGAS-XWR2 Technical Guide
COMMUNICATIONS WIRING
One Modulating Valve, One Ignitor, One Stage (1V1IGN1S)
This conguration is used to control one modulating valve, which
must be placed on Gas Valve 1 (attached to Heat 1 (RLY3)).
For VCM-X Controllers, use an I2C cable connecting to the
appropriate I2C port on the controller.
For all other controllers, use an E-BUS cable connecting to an
E-BUS port on the controller.
Figure 9: Communications Wiring - One Modulating Valve, One Ignitor, One Stage
NOTE: Up to three additional xed heat stages can be
configured by using Heat 2 (RLY4), Heat 3
(RLY6), and Heat 4 (RLY6). If additional xed
stages are required, these should be congured
and wired to the AAON unit controller’s relays.
Fan Enable
Low Speed Fan
Modulating
Gas Valve 1
Proof of Ignition
Signal 1 (24 VAC)
Heat Valve 1
Check your Fan Relay Wiring (RLY1)
Schematic for proper wiring.
Fixed Heat Stage 2
Fixed Heat Stage 3
Fixed Heat Stage 4
ALARM
UP
DOWN
ENTERMENU
MODGAS-XWR2
AAON P/N:ASM01695
LABEL P/N:
G041530 E-BUS
DUAL
I2C
CONNECT
+24 VAC
GND
@ 24 VAC
1 AMP MAX
CONTACT
RATING IS
COMMON
RELAY
OUTPUTS
GAS VALVE
TERMINALS
GAS
VALVE 1
GAS
VALVE 2
INPUT TERMINALS (TYPE)
HEAT ENABLE (BI)
AUX. (BI)
GND
RESET IN (AI)
SAT IN (AI)
GND (AI)
GND
AUX. (AI)
www.aaon.com
LOW SPEED
HEAT 1
HEAT 2
HEAT 3
HEAT 4
PROOF OF IGNITION 1
PROOF OF IGNITION 2
FAN
See SAT OPTIONS Tables for Jumper Settings.
Only one Supply Air Temperature Sensor can be
used per application.
Notes:
1. 24 VAC must be connected so that all ground wires
remain common.
2. All wiring to be in accordance with local and national
electrical codes and specifications.
GV1
CR1
CR2
H1
Line
40 VA
transformer
minimum
Supply Air
Temperature
Sensor
Mount in unit
supply air duct
GND 18-30
VAC
Connect Supply Air Temperature Sensor
to AI2 (VCM-X and VCB-X) or AI3
(VCCX2) and GND on main controller
I2C cable connects to the VCM-X
E-BUS Controller's expansion
port
E-BUS cable connects to the
VCCX2 or VCB-X Controller's
expansion port

16 MODGAS-XWR2 Technical Guide
COMMUNICATIONS WIRING
Two Modulating Valves, Two Ignitors, One Stage (2V2IGN1S)
This conguration is used to control two modulating gas valves
(one on each terminal connector), in which the rst and second
valves operate together for one modulating stage. One valve is
connected to Heat 1 (RLY3) and the second valve is connected
to Heat 2 Relay.
For VCM-X Controllers, use an I2C cable connecting to the
appropriate I2C port on the controller.
For all other controllers, use an E-BUS cable connecting to an
E-BUS port on the controller.
Fan Enable
Low Speed Fan
Modulating
Gas Valve 1
(Modulates with
Valve 2 as 1 Stage
Proof of Ignition
Signal 1 (24 VAC)
Heat Valve 1
Check your Fan Relay Wiring (RLY1)
Schematic for proper wiring.
Heat Valve 2
Fixed Heat Stage 3
Fixed Heat Stage 4
ASSEMBLED IN USA
U15
D13
R
R
R
R
L1
R61 C28
SERIAL #
POWER
COMM
ALARM
STATUS
TB3
GND
AUX AIN
J3
GND
1
2
SAT
OPTIONS
RESET IN
D8
HEAT EN
D7
AUX BIN
GND
J1 U1
TB2
R1
YS102408 REV 3
TB1
RLY1
RLY2
RLY3
RLY4
RLY5
RLY6
COMMON
PO-IGN1
P3
D9
R33
R1
P1
PO-IGN2
P4
D10
R36
R2
Q2
R5
P2
C35
.01UF
R8
R22
R18
R16
R12
R13
R42
R44
D14
SOFTWARE
C22
C27
GAS VALVE 2
GAS VALVE 1
ALARM
UP
DOWN
ENTERMENU
MODGAS-XWR2
AAON P/N:ASM01695
LABEL P/N:
G041530 E-BUS
DUAL
I2C
CONNECT
+24 VAC
GND
@ 24 VAC
1 AMP MAX
CONTACT
RATING IS
COMMON
RELAY
OUTPUTS
GAS VALVE
TERMINALS
GAS
VALVE 1
GAS
VALVE 2
INPUT TERMINALS (TYPE)
HEAT ENABLE (BI)
AUX. (BI)
GND
RESET IN (AI)
SAT IN (AI)
GND (AI)
GND
AUX. (AI)
www.aaon.com
LOW SPEED
HEAT 1
HEAT 2
HEAT 3
HEAT 4
PROOF OF IGNITION 1
PROOF OF IGNITION 2
FAN
Notes:
1. 24 VAC must be connected so that all ground wires
remain common.
2. All wiring to be in accordance with local and national
electrical codes and specifications.
GV1
CR1
CR2
H1
Line
40 VA
transformer
minimum
GND 18-30
VAC
H2
Proof of Ignition
Signal 2 (24 VAC)
GV2
Modulating
Gas Valve 2
(Modulates with
Valve 1 as 1 Stage
See SAT OPTIONS Tables for Jumper Settings.
Only one Supply Air Temperature Sensor can be
used per application.
Supply Air
Temperature
Sensor
Mount in unit
supply air duct
Connect Supply Air Temperature Sensor
to AI2 (VCM-X and VCB-X) or AI3
(VCCX2) and GND on main controller
I2C cable connects to the VCM-X
E-BUS Controller's expansion
port
E-BUS cable connects to the
VCCX2 or VCB-X Controller's
expansion port
Figure 10: Communications Wiring - One Modulating Valve, Two Ignitors, One Stage
NOTE: Up to two additional xed heat stages can be
congured by using Heat 3 (RLY5) and Heat 4
(RLY6). If additional xed stages are required,
these should be configured and wired to the
AAON unit controller’s relays.

17
MODGAS-XWR2 Technical Guide
COMMUNICATIONS WIRING
Two Modulating Valves, Two Ignitors, Two Stages (2V2IGN2S)
This conguration is used to control two modulating gas valves
(one on each terminal connector), in which the first valve
is modulating stage 1 (Gas Valve 1) and the second valve is
modulating stage 2 (Gas Valve 2).The rst valve is attached to
Heat 1 (RLY3) and the second valve is attached to Heat 2 (RLY4).
For VCM-X Controllers, use an I2C cable connecting to the
appropriate I2C port on the controller.
For all other controllers, use an E-BUS cable connecting to an
E-BUS port on the controller.
Fan Enable
Low Speed Fan
Modulating
Gas Valve 1
Proof of Ignition
Signal 1 (24 VAC)
Heat Valve 1
Check your Fan Relay Wiring (RLY1)
Schematic for proper wiring.
Heat Valve 2
Fixed Heat Stage 3
Fixed Heat Stage 4
ALARM
UP
DOWN
ENTERMENU
MODGAS-XWR2
AAON P/N:ASM01695
LABEL P/N:
G041530 E-BUS
DUAL
I2C
CONNECT
+24 VAC
GND
@ 24 VAC
1 AMP MAX
CONTACT
RATING IS
COMMON
RELAY
OUTPUTS
GAS VALVE
TERMINALS
GAS
VALVE 1
GAS
VALVE 2
INPUT TERMINALS (TYPE)
HEAT ENABLE (BI)
AUX. (BI)
GND
RESET IN (AI)
SAT IN (AI)
GND (AI)
GND
AUX. (AI)
www.aaon.com
LOW SPEED
HEAT 1
HEAT 2
HEAT 3
HEAT 4
PROOF OF IGNITION 1
PROOF OF IGNITION 2
FAN
Notes:
1. 24 VAC must be connected so that all ground wires
remain common.
2. All wiring to be in accordance with local and national
electrical codes and specifications.
GV1
CR1
CR2
H1
Line
40 VA
transformer
minimum
GND 18-30
VAC
H2
Modulating
Gas Valve 2
Proof of Ignition
Signal 2 (24 VAC)
GV2
See SAT OPTIONS Tables for Jumper Settings.
Only one Supply Air Temperature Sensor can be
used per application.
Supply Air
Temperature
Sensor
Mount in unit
supply air duct
Connect Supply Air Temperature Sensor
to AI2 (VCM-X and VCB-X) or AI3
(VCCX2) and GND on main controller
I2C cable connects to the VCM-X
E-BUS Controller's expansion
port
E-BUS cable connects to the
VCCX2 or VCB-X Controller's
expansion port
Figure 11: Communications Wiring - Two Modulating Valves, Two Ignitors, Two Stages
NOTE: Up to two additional xed heat stages can be
congured by using Heat 3 (RLY5) and Heat 4
(RLY6). If additional xed stages are required,
these should be configured and wired to the
AAON unit controller’s relays.

18 MODGAS-XWR2 Technical Guide
COMMUNICATIONS WIRING
Secondary Board - 2V2IGN2S
Figure 12: Communications Wiring - Secondary Board 2V2IGN2S
Fan Enable
Low Speed Fan
Modulating
Gas Valve 3
(Slave to Mod
Gas Valve 1)
Proof of Ignition
Signal 3 (24 VAC)
Heat Valve 1
Check your Fan Relay Wiring (RLY1)
Schematic for proper wiring.
Heat Valve 2
Fixed Heat Stage 5
Fixed Heat Stage 6
ALARM
UP
DOWN
ENTERMENU
MODGAS-XWR2
AAON P/N:ASM01695
LABEL P/N:
G041530 E-BUS
DUAL
I2C
CONNECT
+24 VAC
GND
@ 24 VAC
1 AMP MAX
CONTACT
RATING IS
COMMON
RELAY
OUTPUTS
GAS VALVE
TERMINALS
GAS
VALVE 1
GAS
VALVE 2
INPUT TERMINALS (TYPE)
HEAT ENABLE (BI)
AUX. (BI)
GND
RESET IN (AI)
SAT IN (AI)
GND (AI)
GND
AUX. (AI)
www.aaon.com
LOW SPEED
HEAT 1
HEAT 2
HEAT 3
HEAT 4
PROOF OF IGNITION 1
PROOF OF IGNITION 2
FAN
Notes:
1. 24 VAC must be connected so that all ground wires
remain common.
2. All wiring to be in accordance with local and national
electrical codes and specifications.
E-BUS cable connects to the
primary MODGAS-XWR2.
GV3
CR3
CR4
H1
Line
40 VA
transformer
minimum
GND 18-30
VAC
H2
Proof of Ignition
Signal 4 (24 VAC)
GV4
Modulating
Gas Valve 4
(Slave to Mod
Gas Valve 2)
In this conguration, the wiring on Figure 11, page 17 is the
primary portion and Figure 12, this page is the secondary
portion, thus creating four modulating valves as two stages.
NOTE: This conguration is not supported when using
I2C communications.
NOTE: Up to two additional xed heat stages can be
congured by using Heat 3 (RLY5) and Heat 4
(RLY6). If additional xed stages are required,
these should be configured and wired to the
AAON unit controller’s relays.

19
MODGAS-XWR2 Technical Guide
COMMUNICATIONS WIRING
Two Modulating Valves, One Ignitor, One Stage (2V1IGN1S)
Fan Enable
Low Speed Fan
Modulating
Gas Valve 1
Proof of Ignition
Signal 1 (24 VAC)
Heat Valve 1
Check your Fan Relay Wiring (RLY1)
Schematic for proper wiring.
ALARM
UP
DOWN
ENTERMENU
MODGAS-XWR2
AAON P/N:ASM01695
LABEL P/N:
G041530 E-BUS
DUAL
I2C
CONNECT
+24 VAC
GND
@ 24 VAC
1 AMP MAX
CONTACT
RATING IS
COMMON
RELAY
OUTPUTS
GAS VALVE
TERMINALS
GAS
VALVE 1
GAS
VALVE 2
INPUT TERMINALS (TYPE)
HEAT ENABLE (BI)
AUX. (BI)
GND
RESET IN (AI)
SAT IN (AI)
GND (AI)
GND
AUX. (AI)
www.aaon.com
LOW SPEED
HEAT 1
HEAT 2
HEAT 3
HEAT 4
PROOF OF IGNITION 1
PROOF OF IGNITION 2
FAN
See SAT OPTIONS Tables for Jumper Settings.
Only one Supply Air Temperature Sensor can be
used per application.
Notes:
1. 24 VAC must be connected so that all ground wires
remain common.
2. All wiring to be in accordance with local and national
electrical codes and specifications.
GV1
CR1
CR2
H1
Line
40 VA
transformer
minimum
GND 18-30
VAC
Modulating
Gas Valve 2
GV2
Fixed Heat Stage 2
Fixed Heat Stage 3
Fixed Heat Stage 4
Supply Air
Temperature
Sensor
Mount in unit
supply air duct
Connect Supply Air Temperature Sensor
to AI2 (VCM-X and VCB-X) or AI3
(VCCX2) and GND on main controller
I2C cable connects to the VCM-X
E-BUS Controller's expansion
port
E-BUS cable connects to the
VCCX2 or VCB-X Controller's
expansion port
This conguration is used to control two modulating gas valves
(one on each terminal connector), in which the rst and second
valves operate together for one modulating stage. Both valves
are connected to Heat 1 (RLY3).
For VCM-X Controllers, use an I2C cable connecting to the
appropriate I2C port.
For all other controllers, use an E-BUS cable connecting to an
E-BUS port on the controller.
Figure 13: Communications Wiring - Two Modulating Valves, One Ignitor, One Stage
NOTE: Up to three additional xed heat stages can be
configured by using Heat 2 (RLY4), Heat 3
(RLY6), and Heat 4 (RLY6). If additional xed
stages are required, these should be congured
and wired to the AAON unit controller’s relays.

20 MODGAS-XWR2 Technical Guide
COMMUNICATIONS WIRING
Secondary Board - 2V1IGN1S
Figure 14: Stand-Alone Wiring - Secondary Board 2V1IGN1S
Fan Enable
Low Speed Fan
Proof of Ignition
Signal 2 (24 VAC)
Heat Valve 2
Check your Fan Relay Wiring (RLY1)
Schematic for proper wiring.
ASSEMBLED IN USA
U15
D13
R
R
R
R
L1
R61 C28
SERIAL #
POWER
COMM
ALARM
STATUS
TB3
GND
AUX AIN
J3
GND
1
2
SAT
OPTIONS
RESET IN
D8
HEAT EN
D7
AUX BIN
GND
J1 U1
TB2
R1
YS102408 REV 3
TB1
RLY1
RLY2
RLY3
RLY4
RLY5
RLY6
COMMON
PO-IGN1
P3
D9
R33
R1
P1
PO-IGN2
P4
D10
R36
R2
Q2
R5
P2
C35
.01UF
R8
R22
R18
R16
R12
R13
R42
R44
D14
SOFTWARE
C22
C27
GAS VALVE 2
GAS VALVE 1
ALARM
UP
DOWN
ENTERMENU
MODGAS-XWR2
AAON P/N:ASM01695
LABEL P/N:
G041530 E-BUS
DUAL
I2C
CONNECT
+24 VAC
GND
@ 24 VAC
1 AMP MAX
CONTACT
RATING IS
COMMON
RELAY
OUTPUTS
GAS VALVE
TERMINALS
GAS
VALVE 1
GAS
VALVE 2
INPUT TERMINALS (TYPE)
HEAT ENABLE (BI)
AUX. (BI)
GND
RESET IN (AI)
SAT IN (AI)
GND (AI)
GND
AUX. (AI)
www.aaon.com
LOW SPEED
HEAT 1
HEAT 2
HEAT 3
HEAT 4
PROOF OF IGNITION 1
PROOF OF IGNITION 2
FAN
Notes:
1. 24 VAC must be connected so that all ground wires
remain common.
2. All wiring to be in accordance with local and national
electrical codes and specifications.
E-BUS cable connects to the
primary MODGAS-XWR2.
GV3
CR3
CR4
H1
Line
40 VA
transformer
minimum
GND 18-30
VAC
GV4
Fixed Heat Stage 5
Fixed Heat Stage 6
Fixed Heat Stage 7
Modulating
Gas Valve 3
Modulating
Gas Valve 4
In this conguration, the wiring on Figure 13, page 19 is the
primary portion and Figure 14, this page is the secondary
portion, thus creating four modulating valves as one stage.
NOTE: The Four Modulating Valves Primary/Secondary
conguration is not supported when using I2C
communications.
NOTE: Up to three additional xed heat stages can be
configured by using Heat 2 (RLY4), Heat 3
(RLY6), and Heat 4 (RLY6). If additional xed
stages are required, these should be congured
and wired to the AAON unit controller’s relays.