– 14 –
P/N SCM2-0111
Model
SCM
Air to Water Heat Pump — Installation, Operation & Maintenance Manual
Section 8: troubleshooting
Figure 13
Troubleshooting suggestions
Condition
Possible Causes
Verification
Solution
Unit will not start
Incorrect power supply
Check power supply
Supply correct power
Loose or broken wires
Check wiring
Repair or replace wiring
Circuit breaker interrupted
Check for short
Compressor running - insufficient
cooling/heating
Insufficient pipe insulation
Check insulation
Add/repair insulation
Dirty coil
Check coil
Clean Coil
Low water flow
Look for alarm symbol and FL
fault code
Clean strainer screen
Clear blockage
Remove air in piping
Verify operation/condition of
water pump
High compressor discharge pres-
sure in cooling
Insufficient pipe insulation
Check charge
Add/repair insulation
Dirty coil
Check coil
Clean Coil
High compressor discharge pres-
sure in heating
Low water flow
Measure water flow through heat
exchanger
Flow should be a minimum of 11
GPM for SCM060 or 8 GPM for
SCM036
Low compressor suction pres-
sure in cooling
Insufficient/no water flow
Look for alarm symbol and FL
fault code
Clean strainer screen
Clear blockage
Remove air in piping
Verify operation/condition of
water pump
Cooling operation in low ambient
Confirm outdoor ambient is lower
than typical for cooling operation,
e.g. <55°
If low ambient cooling is desired,
contact Technical Support for
procedure to modify fan operat-
ing parameters.
Compressor will not run
Power supply failure
Supply correct power
Failed compressor contactor
Replace contactor
Loose power cable
Check power cable
Tighten power cable
Compressor limit exceeded
Check for compressor symbols 1
and/or 3. If symbol is displayed
but compressor is inactive, ther-
mal overload has been tripped.
This will reset, however root
cause must be determined
Incorrect return water tempera-
ture setting
Check return water temperature
setting
Adjust return water temperature
setting
Low glycol/water flow
Look for alarm symbol and FL
fault code
Clean strainer screen
Clear blockage
Remove air in piping