54
VCCX2 Controller Technical Guide
Head Pressure Control
The RSMV-HP can monitor a Head Pressure Transducer and
control condenser fans to maintain a Head Pressure Setpoint.
The condenser fan will be controlled with a 0-10 VDC output
signal. Head pressure control can also be used to modulate the
water valve when configured as a water source heat pump. The
water valve signal is 2-10 VDC.
Coil Temperature Sensors
The Coil Temperature Sensors are used to measure Coil
Temperature after each evaporator coil line. This temperature
combined with the calculated saturated refrigerant temperature
is used to calculate the Superheat of each individual evaporator
coil. The Superheat is used to drive the Expansion Valves to
maintain a given Superheat Setpoint.
Leaving Water Temperature Sensor
The Leaving Water Temperature Sensor is used to measure the
Leaving Water Temperature when used on a WSHP unit.
CAUTION:
The Shraeder port used for installation of the
suction pressure transducer should be located
in a vertical position of the suction line to
prevent refrigerant oil from accumulating in
the sensor.
NOTE:
If there are two Compressors on a single circuit (a
tandem circuit), Suction Pressure 2, Head Pressure
2, and Condenser Signal 2 would not be used.
18-30 VAC
GND
Line Voltage
Size transformer for
correct total load.
RSMV = 18 VA
RSMV-HP
REVERSING VALVE
COMPRESSOR 2 ENABLE
COMPRESSOR 1 ENABLE
24 VAC ONLY
RD
WH
BK
GRN
Expansion
Valve 1
RD
WH
BK
GRN
Expansion
Valve 2
RD
WH
BK
GRN
Expansion
Valve 3
RD
WH
BK
GRN
Expansion
Valve 4
CONDENSER ENABLE
Connect to
VCCX2 Controller
Note:
All relay outputs are normally
open and rated for 24 VAC
power only.
1 amp maximum load.
Figure 35: RSMV-HP Outputs Wiring
WIRING
RSMV-HP Outputs