AAON MHGRVX-A2 Technical Guide

22MHGRVX-A2 Module Technical Guide
TROUBLESHOOTING
Alarms
Supply Air Temperature Failure
• Verify that the Supply Air Temperature Sensor is connected
to the SAT and GND on the MHGRVX-A2 or MODGAS
module (Stand-Alone Mode) or to AI2 and GND on the
AAON unit controller (communicating mode).
• Remove SAT and GND wiring from MHGRVX-A2 and
ohm sensor out (this may indicate open or failed wiring).
Refer to chart in back of this guide for readings.
• Verify the SAT OPTIONS jumper settings on the
MHGRVX-A2 for the Supply Air Temperature Sensor.
Communications Loss
• Check COMM LED on MHGRVX-A2.
• Verify 24 VAC power to all interconnected AAON unit
controllers.
• Verify E-BUS connection between the MHGRVX-A2 and
associated AAON unit controllers.
• In communication mode (connected to an AAON unit
controller with modular cable), conrm that module’s
MHGRVX-A2 status screen displays Position % and that
main screens show COMM MODE.
ALARM LED
REHEAT ENABLE LED
HEAT OVERRIDE LED
COOL OVERRIDE LED
FAN RELAY LED
COMPRESSOR
RELAY LED
VALVE RELAY LED
AUX RELAY LED
STATUS LED
ALARM LED
COMM LED
POWER LED
CONDENSER
DRIVE LED
REHEAT VALVE DRIVE
THREE-WAY VALVE LED
D8
R2
J3
MODGASx
MODGAS
NORMAL
R1
SAT OPTIONS
SAT
GND
COOL OVRD
HEAT OVRD
REHEAT EN
RESET IN
AUX IN
GND
TB2
LC
FAN
COMP
VALVE
AUX
COMMON
TB1
STATUS
ALARM
COMM
POWER
CONDENSOR DRIVE
BLACK
WHITE
RED
GREEN
OPENING
TB3
REHEAT DRIVE
BLACK
WHITE
GREEN
RED
OPENING
TB4
C23
.01uF
ALARM
UP
DOWN
ENTERMENU
FAN
COMPRESSOR
REHEAT VALVE
AUX
COMMON
OUTPUTS
RELAY
CONDENSER
DRIVE TERMINALS
BLACK
WHITE
RED
GREEN
GND
RHT EN (BI)
AUX INPUT (AI)
RESET SIG (AI)
HEAT OVR (BI)
COOL OVR (BI)
INPUTTERMINALS(TYPE)
GND
SAT (AI)
@ 24 VAC
CONTACT
RATING IS
1 AMP MAX
MHGRVX-A2
AAON P/N:ASM06926
www.aaon.com
LABEL P/N:
G112600
E-BUS
CONNECT
CONNECT
E-BUS
+24VAC
GND
REHEAT VALVE
DRIVE TERMINALS
BLACK
WHITE
GREEN
RED
Figure 5: MHGRVX-A2 LED Locations and Descriptions

AAON MHGRVX-A2 Specifications

General

Brand	AAON
Model	MHGRVX-A2
Category	Control Unit
Language	English