Orion System MHGRV III - Manual (Page 4)

MHGRV III Controller Technical Guide
Operator Interface 4
General
The following inputs and outputs are available on the MHGRV III
controller For component locations of the inputs, outputs and wiring,
see Figures 2 and 3.
Analog Inputs
SAT: Supply Air Temperature Sensor
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.
RESET IN: Reset Signal
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.
AUX IN: Valve Force Position Signal
The modulating HGR valves can be forced to a fi xed position by supply-
ing a 0-10 VDC signal to the AUX IN input. The setpoint and reset limit
switches must both be set to 1 to enable the valve force to work.
24 VAC Contact Closure Inputs
RHT EN: Dehumidifi cation
When a call for dehumidifi cation is initiated by another controller, this
interlocked 24 VAC wet contact closure is used to enable the MHGRV
III controller.
HEAT OVR: Heating Override
When a call for heating is initiated by the HVAC unit, this interlocked 24
VAC wet contact closure is used to override the MHGRV III controller
dehumidifi cation mode.
COOL OVR: Cooling Override
When a call for cooling is initiated by the HVAC unit, this interlocked 24
VAC wet contact closure is used to override the MHGRV III controller
dehumidifi cation mode.
Analog Outputs
AOUT 1: Valve Position Signal
The valve position signal is a 0-10 VDC signal that matches the position
of the valve. 0V = 0%, 10V = 100%.
Relay Outputs
COM: Relay Common
Requires 24 VAC from transformer.
FAN: Fan Enable
When a call for Dehumidifi cation, Cooling Override, or Heating Over-
ride 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 Dehu-
midifi cation is received and the modulating HGR valve is at 100%, this
relay output will be closed to energize the 2 Position HGR Valve. The
relay will open when the modulating HGR valve is at 0%.
Modulating HGR Valve Outputs
CG/HR:
This output is connected to the Condenser HGR Valve Green Wire
Termination and to the Reheat HGR Valve Red Wire Termination to
control their modulation.
CR/HG:
This output is connected to the Condenser HGR Valve Red Wire Termi-
nation and to the Reheat HGR Valve Green Wire Termination to control
their modulation.
CW/HW:
This output is connected to the Condenser HGR Valve White Wire
Termination and to the Reheat HGR Valve White Wire Termination to
control their modulation.
CB/HB:
This output is connected to the Condenser HGR Valve Black Wire
Termination and to the Reheat HGR Valve Black Wire Termination to
control their modulation.
Inputs and Outputs