NOTES
MHGRV-X Field Technical Guide
20
Appendix B - 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
.
STAND-ALONE MODE OPERATION
Step 1:
Disconnect power from the MHGRV II Controller.
Step 2:
Disconnect the Supply Air Temperature Sensor from 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.
Step 3:
Separate the HGR Valve wires and the Condenser Valve
wires onto the appropriate Reheat Drive and Condenser
Drive terminal blocks per
Figure 3, page 6
. Wire all
other inputs and outputs per
Figure 3
, also.
Step 4:
Set the SAT Options Jumper per
Table 8, page 19
.
Step 5:
Connect power to the MHGRV-X Controller.
COMMUNICATIONS MODE OPERATION
Step 1:
Disconnect power from the MHGRV-II Controller.
Step 2:
The Supply Air Temperature Sensor needs to remain
installed on whatever controller it is currently on. If it
is currently installed on the MHGRV II Controller, then
reinstall it on the MHGRV-X Controller. If it is currently
installed on the main unit controller or on a connected
MODGAS Controller, it needs to remain there.
Step 3:
Set the SAT Options Jumper per
Table 9, page 19
.
Step 4:
Connect power to the MHGRV-X Controller.
Figure 7: MHGRV-X Controller
