27
R e s i d e n t i a l H & V - 6 0 H z H F C - 4 1 0 A
R e v : O c t o b e r 5 , 2 0 2 1
c l i m a t e m a s t e r.c o m
Electrical - Low Voltage Wiring
Thermostat Connections
The thermostat should be wired directly to the CXM board
(units with PSC fan). Units with optional ECM motor include
factory wiring from the CXM board to the ECM interface
board. Thermostat wiring for these units should be connected
to the ECM interface board. Figure 18 shows wiring for TS
units with PSC or optional ECM motor. See “Electrical –
Thermostat” for specific terminal connections.
Low Water Temperature Cutout Selection
The CXM control allows the field selection of low water (or
water-antifreeze solution) temperature limit by clipping jumper
JW3, which changes the sensing temperature associated
with thermistor FP1. Note that the FP1 thermistor is located
on the refrigerant line between the coaxial heat exchanger
and expansion device (TXV). Therefore, FP1 is sensing
refrigerant temperature, not water temperature, which is
a better indication of how water flow rate/temperature is
affecting the refrigeration circuit.
The factory setting for FP1 is for systems using water (30°F
[-1.1°C] refrigerant temperature). In low water temperature
(extended range) applications with antifreeze (most ground
loops), jumper JW3 should be clipped as shown in Figure
19 to change the setting to 10°F [-12.2°C] refrigerant
temperature, a more suitable temperature when using
an antifreeze solution. All residential units include water/
refrigerant circuit insulation to prevent internal condensation,
which is required when operating with entering water
temperatures below 59°F [15°C].
Figure 18: TS Low Voltage Field Wiring
Low voltage field wiring for units with ECM fan
Low voltage
field wiring
for units with
PSC FAN
(ECM board
will not be
present)
Figure 19: FP1 Limit Setting
FP1
FP2
CXM PCB
JW3-FP1.
jumper should
be clipped for
low temperature
operation
