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MHGRVX-A2 Module Technical Guide
OPERATION MODES
Modes of Operation
Communications Operation
In this mode, the MHGRVX-A2 behaves as an expansion board for
an AAON unit controller. The controller begins the dehumidification
process when the AAON unit controller makes a request to the
MHGRVX-A2 for dehumidification. At that time, the controller will
activate the “FAN” output to energize the HVAC unit fan. At the
same time, the controller will initiate Cooling Mode by energizing
the “CMP” output starting the HVAC unit compressor.
At this time, the MHGRVX-A2 will start to modulate the Modulating
Hot Gas Reheat Valve. The controller will modulate the MHGR
valve to maintain the Supply Air Temperature Setpoint by activating
the stepper motor outputs on the MHGR valve. The Supply Air
Setpoint is set by programming the HVAC unit controller. If Supply
Air Temperature Reset is used, it will initiate when the HVAC unit
controller ends a request to reset the Supply Air Temperature.
The Supply Air Temperature will be reset towards the Supply Air
Reset Temperature Setpoint stored in the HVAC unit controller. It
will send a request to move towards the Supply Air Temperature
Reset Setpoint based on its setpoints and configuration.
The controller will conclude the Dehumidification process when the
HVAC unit controller sends a request to terminate Dehumidification
or a Cooling or Heating Override request is made by the HVAC unit
controller. Any setpoints or signals at the inputs to the MHGRVX-A2
will be ignored.
Auxiliary Mode Communicating
1. Same as the Stand-Alone Auxiliary Mode, but the Reheat
Enable and Auxiliary Valve position will be sent using
E-BUS commands.