Miami Heat Pump HPX Series, Installation Manual & Owner'S Manual

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6. Troubleshooting
Possible Problems, Causes & Solutions
Problem Possible Cause Checks and Corrections
Entire unit does
not run
Power Supply OFF Apply power, close disconnect switch.
Blown Fuse Replace fuse or reset circuit breaker. Check for correct fuses.
Voltage Supply Low Contact local power company.
Thermostat
Set the fan to “ON”, the fan should run. Set thermostat to “COOL” and lowest temperature setting. The unit should run in
the cooling mode (reversing valve energized). Set unit to “HEAT” and the highest temperature setting. The unit should run
in the heating mode. If neither the blower nor compressor runs in all three cases, the thermostat can be miswired or faulty.
To ensure miswired or faulty thermostat verify 24 volts is available on condensing section low voltage terminal strip
between “R” and “C”, “Y” and “C” and “O” and “C” if the blower does not operate. Verify 24 volts between terminals “G”
and “C” in air handler. Replace thermostat if defected.
Blower
operates but
compressor
does not
Thermostat Check setting, calibration and wiring.
Wiring Check for loose or broken wire at compressor, or contactor.
Capacitor Check compressor capacitor if applicable.
Safety Controls Check lock-out relay for fault signal.
Compressor Overload Open If the compressor is cool and the overload will not reset, replace compressor.
Compressor Motor Grounded Internal winding grounded to the compressor shell. Replace compressor. If compressor burnout, install suction filter dryer.
Compressor Windings Open
After compressor has cooled, check continuity of the compressor windings. If the windings are open, replace the
compressor.
Unit OFF on
high pressure
switch
Discharge Pressure too High
In “COOLING” mode: lack of or inadequate water flow. Entering water temperature too warm scaled or plugged condenser.
In “HEATING” mode: lack of or inadequate air flow. Blower inoperative clogged filter or restrictions in ductwork.
Refrigeration Charge The unit is overcharged with refrigerant. Reclaim refrigerant, evacuate and recharge with factory recommended charge.
High Pressure Check defective or improperly calibrated high pressure switch.
Unit OFF on low
pressure switch
Suction Pressure too Low
In “COOLING” mode: lack of or inadequate air flow. Entering air temperature too cold. Blower inoperative clogged filter or
restriction in ductwork.
In “HEATING” mode: lack of or inadequate water flow. Entering water temperature too cold. Scaled or plugged condenser.
Refrigerant Charge The unit is low on refrigerant. Check for refrigerant leak, repair, evaluate and recharge with factory recommended charge.
Low Pressure Switch Check for defected or improperly calibrated low pressure switch.
Unit Short Cycle
Unit Oversized Recalculate cooling and/or heating loads.
Thermostat Thermostat installed near a supply air grill, relocate thermostat. Readjust heat anticipator.
Wiring and Controls Loose connections in a wiring or defective compressor contactor.
Insufficient
Cooling or
Heating
Unit Undersized Recalculate heating and/or cooling loads. If excessive, possibly adding insulation and shading will rectify the problem.
Loss of Conditioned Air by Leaks Check for leaks in ductwork or introduction of ambient air through doors or windows.
Airflow Lack of adequate airflow or improper distribution of air. Replace dirty filter.
Refrigerant Charge Low refrigerant charge causing inefficient operation.
Compressor Check for defective compressor. If discharge is too low and suction pressure is too high. Compressor is not pumping
properly. Replace compressor.
Reversing Valve Defective reversing valve creating bypass of refrigerant from discharged to suction side of compressor. Replace reversing
valve.
Operating Pressures Compare unit operating pressures to pressure / temperature chart of the unit.
TXV/Capillary Tubes Check for possible restriction or defect. Replace if necessary.
Moisture, Non-condensable
The refrigeration system may be contaminated with moisture or non-condensable. Reclaim refrigerant, evacuate and
recharge with factory recommended charge. Note: a liquid line dryer may be required.
20233 NE 15
th
Court Miami, Fl. 33147 | Phone (866) 407-8535 | Fax (866) 406-6603