Orion System MHGRV-X - Manual (Page 7)

MHGRV-X Field Technical Guide
INPUTS & OUTPUTS
7
Inputs and Outputs
Table 1: MHGRV-X Controller Inputs & Outputs
NOTE: All analog and 24 VAC contact closure inputs are used
only in Stand Alone operation.
Analog Inputs
SAT: Supply Air Temperature Sensor
Used in stand-alone operation and when MODGAS is connected
to a CAV/VAV or MUA Controller. The Supply Air Temperature
Sensor is the main control input. This sensor has to be installed for
the unit to operate. The Supply Air Temperature Sensor is located
in the discharge air stream and monitors the HVAC unit’s Supply
Air Temperature to maintain the Supply Air Temperature Setpoint.
RST IN: Reset Signal
Used only in stand-alone operation. The Discharge Temperature
Setpoint can be reset by supplying a 0-10 VDC signal to the RESET
IN low voltage terminal block. This reset signal is optional and need
only be used if you require resetting of the discharge air temperature.
I/O Map
The following inputs and outputs are available on the MHGRV-X
Controller. See Table 1 below to reference the Input/Output Map.
Analog Inputs
1 Supply Temperature
2 Reset Signal
3 AUX Input - Future Application
Binary Inputs
1 Reheat Enable
2 Heating Override
3 Cooling Override
Relays
1 Fan
2 Compressor
3 Reheat Valve
4 Auxiliary
Binary Inputs
REHEAT EN: Reheat Enable Contact
Used only in stand-alone operation. When a call for dehumidifi cation
is initiated by another controller, this interlocked 24 VAC wet contact
closure is used to enable the MHGRV-X controller.
HEAT OVR: Heating Override
Used only in stand-alone operation. When a call for heating is initi-
ated by the HVAC unit, this interlocked 24 VAC wet contact closure
is used to override the MHGRV-X controller dehumidifi cation mode.
COOL OVR: Cooling Override
Used only in stand-alone operation. When a call for cooling is initi-
ated by the HVAC unit, this interlocked 24 VAC wet contact closure
is used to override the MHGRV-X controller dehumidifi cation mode.
Relay Outputs
FAN: Fan Enable
When a call for Dehumidifi cation, Cooling Override, or Heating
Override is received, this relay output will be closed to energize the
HVAC unit Supply Fan.
CMP: Compressor Enable
When a call for Dehumidifi cation or Cooling Override is received,
this relay output will be closed to energize the Compressor(s).
VALVE: Reheat Solenoid Valve
When a call for Dehumidifi cation is active for 30 seconds, this
relay output will be closed to energize the Hot Gas Solenoid Valve.
AUX: 2 Position HGR Valve
Used on larger capacity systems that have an optional 2 Position
HGR Valve in addition to the Modulating HGR Valve. When a call
for Dehumidifi cation is received if the modulating HGR valve is at
100% and the Supply Air Temperature is at least 5 degrees below
setpoint, this relay output will energize to enable the 2 Position HGR
Valve. The relay will de-energize when the modulating HGR valve
closes to 0% and the Supply Air Temperature is at least 5 degrees
above setpoint. The modulating valve is then enabled to modulate
to maintain the Supply Air Setpoint.
COM: Relay Common
Requires 24 VAC from transformer.