Appendix B: Mhgrv Ii; Mhgrv-X Replacement Of Mhgrv Ii; Figure 7: Mhgrv-X - AAON MHGRV-X Field Technical Manual

APPENDIX B: MHGRV II

MHGRV-X Replacement of MHGRV II

Replacing the MHGRV II with the
MHGRV-X
The drop-in replacement involves a few easy steps.
Refer to Figure 7, this page.
Stand-Alone Mode Operation
Disconnect power from the MHGRV II.
Step 1:
Disconnect the Supply Air Temperature Sensor from
Step 2:
the MHGRV II and wire it to the MHGRV-X. If the
Supply Air Temperature Sensor is being shared with a
Stand-Alone MODGAS Controller, maintain the same
wiring with the MODGAS Controller.
Separate the HGR Valve wires and the Condenser Valve
Step 3:
wires onto the appropriate Reheat Drive and Condenser
Drive terminal blocks per Figure 3, page 8. Wire all
other inputs and outputs per Figure 3.
Set the SAT Options Jumper per Table 9, page 21.
Step 4:
Connect power to the MHGRV-X.
Step 5:
Connect to a MHGRV-X in Stand-Alone Mode
or when using a VAV/CAV or MUA controller.
If also using a MODGAS controller
in Stand-Alone Mode, the SAT Sensor
connects to the MODGAS controller.
Supply
Air Temperature
Sensor
Mount In Supply
Air Duct
Only one Supply Air Temperature Sensor
can be used per application.
2
I C Cable connects to
AAON unit controller's port
Figure 7: MHGRV-X Replacement Wiring
22
Communications Mode Operation
Disconnect power from the MHGRV-II.
Step 1:
The Supply Air Temperature Sensor needs to remain
Step 2:
installed on whatever controller it is currently on. If it
is currently installed on the MHGRV II then reinstall
it on the MHGRV-X. If it is currently installed on the
main unit controller or on a connected MODGAS, it
needs to remain there.
Set the SAT Options Jumper per Table 10, page 21.
Step 3:
Connect power to the MHGRV-X.
Step 4:
ALARM
MENU
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.
MHGRV-X Field Technical Guide
UP
ENTER
DOWN
Line Voltage