Troubleshooting | 37SM Series Heat Pump
8733942411 (2017/06)Revised 07-17
UNIT TROUBLESHOOTING
Problem Mode Check Possible Cause Action
Cooling Heating
Unit not shifting into
Cooling and Heating
X X
Reversing valve solenoid
energized
Faulty solenoid
Check that the reversing valve solenoid is
receiving 24 VAC. If so,
Check the resistance of the solenoid - an open
circuit may indicate a burned out solenoid.
Reversing valve solenoid
not energized
Miswired/faulty
thermostat
Check that the reversing valve thermostat wire is
connected to the "O" terminal of the thermostat.
Check for a contact closure between "O" and "R".
Loose wire on "O"
terminal
Check that the wires from the thermostat to the
unit are securely connected and that the wires
from the electrical box to the reversing valve are
connected.
Excessively cold supply
air temperature in
cooling or excessively
hot supply air
temperature in heating
X
X
Reduced air flow
Dirty Filter Replace filter.
Fan speed too low
Consult blower performance table and increase
fan speed if possible.
Excessive duct pressure
drop
Consult blower performance table and increase
fan speed if possible.
Excessively warm
supply air temperature
in cooling and/or
excessively cool air in
heating
X
X
Air flow too high
Fan speed setting too
high
Consult blower performance table and reduce fan
speed if possible.
High or low water
temperature
Inlet water temperature
out of range
Check unit capacity vs. water temperature.
Air leakage
Leaky duct work Inspect duct work.
Loss of refrigeration
capacity
Low refrigerant Check refrigerant pressures with gauge set.
High humidity X
Air flow too high Fan speed setting too
high
Consult blower performance table and reduce fan
speed if possible.
Loss of refrigeration
capacity
Low refrigerant Check refrigerant pressures with gauge set.
Short cycling
Unit oversized Check unit performance against building load
calculations.
Poor thermostat location Make sure that thermostat is not located by a
supply air duct.
To Next Page
Loading...
