HTV/HTD/HTH SERIES Heat Controller, Inc.
25
Electrical - Power & Low Voltage Wiring
ELECTRICAL - POWER & LOW VOLTAGE WIRING
ELECTRICAL - LOW VOLTAGE WIRING
THERMOSTAT CONNECTIONS
Units include factory wiring from the CXM
board to the ECM interface board.
Thermostat wiring should be connected to
the ECM interface board.
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.
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 refrigerant temperature).
In low water temperature (extended range)
applications with antifreeze (most ground
loops), jumper JW3 should be clipped as
shown in Figure 10 to change the setting to
10°F refrigerant temperature, a more
suitable temperature when using an
antifreeze solution. All Heat Controller
units operating with entering water
temperatures below 59°F include the
water/refrigerant circuit insulation package
to prevent internal condensation.
Figure 10: FP1 Limit Setting
.
JW3-FP1
Jumper should be clipped for low
temperature operation
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