Troubleshooting - Carrier Aquazone 50PEC09-18 Installation, Start-Up And Service Instructions Manual

TROUBLESHOOTING

Troubleshooting Checks and Correction column in Table 13 may
reflect a possible fault that may be one of, or a combination of
causes and solutions. Check each cause and adopt "process of
elimination" and/or verification of each before making any
conclusion.
PROBLEM
ENTIRE UNIT DOES
NOT RUN
BLOWER OPER-
Compressor Overload
ATES BUT COM-
PRESSOR DOES
NOT.
Compressor Windings
Discharge Pressure Too
UNIT OFF ON HIGH
PRESSURE
CONTROL
High Pressure Switch
Suction Pressure Too
UNIT OFF ON LOW
PRESSURE
CONTROL
Low Pressure Switch
UNIT SHORT
CYCLES
Loss of Conditioned Air
INSUFFICIENT
COOLING OR
HEATING
Operating Pressures
Table 13 — Troubleshooting
POSSIBLE CAUSE
Power Supply Off Apply power, close disconnect.
Blown Fuse Replace fuse or reset circuit breaker. Check for correct fuses
If voltage is below minimum voltage specified on unit data plate, contact local power
Voltage Supply Low
company.
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 nei-
ther the blower nor the compressor run in all three cases, the thermostat could be miswired
Thermostat
or unit-mounted controller faulty. To ensure miswired 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.
Thermostat Check setting, calibration, and wiring.
Wiring Check for loose or broken wires at compressor, capacitor, or contactor.
Safety Controls Check C and D package red default LED for blink code.
If the compressor is cool and the overload will not reset, replace compressor.
Open
Compressor Motor Internal winding grounded to the compressor shell. Replace compressor. If compressor
Grounded burnout, install suction filter drier.
After compressor has cooled, check continuity of the compressor windings. If the windings
Open are open, replace the compressor.
In "COOLING" mode: Lack of or inadequate water flow. Entering water temperature is too
warm. Scaled or plugged condenser. In "HEATING" mode: Lack of or inadequate air flow.
High
Blower inoperative, clogged filter or restrictions in duct work.
The unit is overcharged with refrigerant. Recover refrigerant, evacuate and recharge with
Refrigerant Charge
factory recommended charge.
Check for defective or improperly calibrated high pressure switch.
In "COOLING" mode: Lack of or inadequate air flow. Entering air temperature is too cold.
Blower inoperative, clogged filter or restrictions in duct work. In "HEATING" mode: Lack of
Low or inadequate water flow. Entering water temperature is too cold. Scaled or plugged
condenser.
The unit is low on refrigerant. Check for refrigerant leaks, repair, evacuate and recharge
Refrigerant Charge
with factory recommended charge.
Check for defective or improperly calibrated low pressure switch.
Unit Oversized Recalculate heating and or cooling loads.
Thermostat Thermostat installed near a supply air grill; relocate thermostat. Readjust heat anticipator.
Wiring and Controls Check for defective or improperly calibrated low pressure switch.
Recalculate heating and or cooling loads. If excessive, possibly adding insulation and
Unit Undersized
shading will rectify the problem.
Check for leaks in duct work or introduction of ambient air through doors or windows.
By Leakage
Airflow Lack of adequate air flow or improper distribution of air. Replace dirty filter.
Refrigerant Charge Low on refrigerant charge causing inefficient operation.
Check for defective compressor. If discharge is too low and suction pressure is too high,
Compressor
compressor is not pumping properly. Replace compressor.
Defective reversing valve creating bypass of refrigerant from discharge of suction side of
Reversing Valve
compressor. Replace reversing valve.
Compare unit operation pressures to the pressure/temperature chart for the unit.
Check thermostatic expansion valve (TXV) for possible restriction or defect. Replace if
TXV
necessary.
The refrigerant system may be contaminated with moisture or non condensable. Recover
Moisture,
refrigerant, replace filter dryer, evacuate the refrigerant system, and recharge with factory
Non Condensable
recommended charge.
Periodic lockouts almost always are caused by air or water flow
problems. The lockout (shutdown) of the unit is a normal protec-
tive measure in the design of the equipment. If continual lockouts
occur, call a technician immediately and have them check for: wa-
ter flow problems, water temperature problems, air flow problems
or air temperature problems. Use of the pressure and temperature
charts for the unit may be required to properly determine the
cause.
CHECKS AND CORRECTION
23