OM 1239
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Troubleshooting the water source heat pump unit
Figure 16: Troubleshooting guide - unit operation
Unit
Low voltage, check
power supply voltage
Fuse may be blown,
circuit breaker is open
Wire may be loose or broken.
Replace or tighten wires
Unit control, check thermostat
for correct wiring or faulty
thermostat
Check wiring - loose or
broken and check for faulty
connection
Check relays and contacts,
also capacitor and wiring
Check high pressure switch,
low pressure switch and low
temperature switch to see if
unit is cycling on the safety
Check to see if the reversing
valve is not hung up and is
operating correctly
Check condensate overflow
switch in cool mode of
operation
Compressor attempts to
start but does not
Check compressor wiring
for defective wiring or loose
connection
Check for faulty compressor
capacitor
Insufficient cooling or
heating
Check for lock rotor amp
draw
Check for defective
compressor internal windings
with ohm meter
Check for proper air flow -
filter could be dirty
Check for low refrigerant
charge
Check amp draw on blower
assembly
Fan operates,
compressor does not
Compressor runs
in short cycle
Neither fan, nor compressor
runs and all LED lights
are off
For unit size 290 verify compres-
sor protector fault status
Check wiring - loose or broken
and check for bad connection
High or Low pressure lockout
A. Cool mode, check water flow
B. Heating mode, check air flow
C. Check reversing valve for
proper valve position
Check compressor overload -
make sure it is closed
Check compressor to ground, or
for internal short to ground
Compressor winding may be
open. Check continuity with
ohm meter
Check thermostat for
improper location
Check blower assembly for
dirt or faulty fan motor
capacity
Check thermostat for
proper location
Check for proper water flow
and delta T (°F)
