Troubleshooting | 35SM Series Heat Pump
8733942411 (2017/06)Revised 07-17
UNIT TROUBLESHOOTING
Problem Mode Check Possible Cause Action
Cooling Heating
No compressor
operation but fan runs
X
Is fault LED Blinking 4
times?
Condensate fault - poor
drainage
Check condensate pan for high water level.
Check drain line for blockages, double trapping
or inadequate trapping.
Condensate fault -
blocked return air
Check condensate pan for high water level.
Check air filter and return air
duct work for blockage. Check that
there is adequate space between the return air
opening and walls or other obstructions on free
return applications.
X
Is fault LED Blinking 5
times?
Brown out fault - low
supply voltage
Check primary voltage - ensure it is within the
limits listed on the unit data plate.
Brown out fault -
overloaded control circuit
Check control voltage - if it is below
18 V check accessories connected to the unit and
ensure that they do not exceed the VA draw
shown on page # 11.
Brown out fault - bad
thermostat connection
Check that thermostat wiring is proper gauge and
length, that it is not damaged and that all
connections at the thermostat and heat pump are
secure.
X
Is fault LED Blinking 6
times?
Freeze fault, air coil - no
or low air flow
Check fan motor for proper operation.
Check air filter
Inspect air coil for dirt/debris
Check duct work - are dampers closed or
blocked?
Freeze fault, air coil -
blocked return air
Check that there is adequate space between the
return air opening and walls or other obstructions
on free return applications.
Freeze fault, air coil - low
refrigerant
Check refrigerant pressure with gauge set.
X
X
No fault LED - contactor
not energized
Thermostat not calling for
compressor operation
Ensure that the thermostat is on and calling for
"Y"
Bad thermostat
connection
Check "Y" connection from thermostat. Ensure
that there is 24 VAC between "Y" and "C".
Loose wire to contactor
coil
Check wiring - ensure that there is 24 VAC across
the contactor coil.
Burned out contactor coil Test contactor with 24VAC (between
"R" and "C"). Ohm contactor coil - an open circuit
indicates a burned coil.
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