Carrier Aquazone 50HQP Series Installation, Start-Up And Service Instructions Manual page 45

PROBLEM
ENTIRE UNIT DOES
NOT RUN
BLOWER OPERATES
BUT COMPRESSOR
DOES NOT
UNIT OFF ON
HIGH PRESSURE
CONTROL
UNIT OFF ON
LOW PRESSURE
CONTROL
UNIT SHORT
CYCLES
INSUFFICIENT
COOLING OR
HEATING
LEGEND
LED — Light Emitting Diode
TXV — Thermostatic Expansion Valve
Table 9 — Troubleshooting
POSSIBLE CAUSE
Power supply off
Blown fuse
Voltage supply low
Thermostat
Thermostat
Wiring
Safety controls
Compressor overload open
Compressor motor grounded
Compressor windings open
Discharge pressure too high
Refrigerant charge
High pressure
Suction pressure too low
Refrigerant charge
Low pressure switch
Unit oversized
Thermostat
Wiring and controls
Unit undersized
Loss of conditioned air
by leaks
Airflow
Refrigerant charge
Compressor
Reversing valve
Operating pressures
TXV/Capillary Tube
Moisture, noncondensables
Apply power, close disconnect
Replace fuse or reset circuit breaker. Check for correct fuses.
If voltage is below minimum voltage specified on unit data plate, contact local power
company.
Set the fan to "ON", the fan should run. Set thermostat to "COOL" and lowest tem-
perature 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 or compressor run in all three cases, the thermo-
stat could be mis-wired or faulty.To ensure mis-wired or faulty thermostat verify 24
volts is available on the 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 the air handler. Replace the thermostat if defective.
Check setting, calibration, and wiring.
Check for loose or broken wires at compressor, capacitor, or contactor.
Check Complete C/Deluxe D board red default LED for Blink Code
If the compressor is cool and the overload will not reset, replace compressor.
Internal winding grounded to the compressor shell. Replace compressor. If compres-
sor burnout, install suction filter drier.
After compressor has cooled, check continuity of the compressor windings. If the
windings are open, replace the compressor.
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 airflow. Blower inoperative, clogged filter
or restrictions in ductwork.
The unit is overcharged with refrigerant. Recover refrigerant, evacuate and recharge
with factory recommended charge.
Check for defective or improperly calibrated high pressure switch.
In "COOLING" mode: Lack of or inadequate air flow. Entering air temperature too
cold. Blower inoperative, clogged filter, or restrictions in ductwork.
In "HEATING" mode: Lack of or inadequate water flow. Entering water temperature
too cold. Scaled or plugged condenser.
The unit is low on refrigerant. Check for refrigerant leak, repair, evacuate and
recharge with factory recommended charge.
Check for defective or improperly calibrated low-pressure switch.
Recalculate heating and or cooling loads.
Thermostat installed near a supply air grille, relocate thermostat. Readjust heat
anticipator.
Loose connections in the wiring or a defective compressor contactor.
Recalculate heating and or cooling loads. If excessive, possibly adding insulation
and shading will rectify the problem.
Check for leaks in ductwork or introduction of ambient air through doors or windows.
Lack of adequate airflow or improper distribution of air. Replace dirty filter.
Low on refrigerant charge causing inefficient operation.
Check for defective compressor. If discharge is too low and suction pressure is too
high, compressor is not pumping properly. Replace compressor.
Defective reversing valve creating bypass of refrigerant from discharge to suction
side of compressor. Replace reversing valve.
Compare unit operating pressures to the pressure / temperature chart for the unit.
Check for possible restriction or defect. Replace if necessary.
The refrigerant system may be contaminated with moisture or noncondensables.
Recover refrigerant, evacuate and recharge with factory recommended charge.
Note: a liquid line drier may be required.
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SOLUTION