SECTION II: INSTALLATION AND MAINTENANCE
35
II.12 CHECK-LIST
PROBLEM RECOMMENDED ACTION
1 - OUTLET PRESSURE HIGH
Insufficient cooling air at air-side exchanger: check clearances and make sure coils are not obstructed.
Fan does not run check fan operation.
Excessive refrigerant charge. drain the excess.
2 - OUTLET PRESSURE LOW
1 - identify and eliminate any leaks;
Insufficient refrigerant charge.
2 - restore correct charge.
Mechanical problems in the compressor: replace compressor
3 - INLET PRESSURE HIGH
Excessive thermal load: check system sizing, infiltrations and insulation.
Irregular operation of the expansion valve: check operation.
Mechanical problems in the compressor: replace compressor
4 - INLET PRESSURE LOW
1 - identify and eliminate any leaks;
Insufficient refrigerant charge.
2 - restore correct charge.
Filter partially obstructed (appears frosted): replace filter.
Irregular operation of the expansion valve: check operation.
Presence of air in the water system: bleed the water system.
Insufficient water flow: check circulation pump operation.
5 - THE COMPRESSOR DOES NOT START
Microprocessor board alarm: identify alarm and take appropriate action.
No voltage, switch open: close the switch.
1-reset the switch / electronic control;
Overload protection triggered:
2-check the unit at start up.
No request for cooling with user system set point correct: check and if necessary wait for cooling request.
Working set point too high: check and if necessary readjust set-point.
Defective contactors: replace contactor.
Compressor electric motor failure: check for short circuit.
6 - THE COMPRESSOR MAKES A BUZZING NOISE
Incorrect power supply voltage: check voltage, investigate causes.
Compressor contactor stuck: replace contactor.
Mechanical problems in the compressor: replace compressor
7 - THE COMPRESSOR STARTS AND STOPS
Faulty low pressure switch: check pressure switch calibration and operation.
1 - identify and eliminate any leaks;
Insufficient refrigerant charge.
2 - restore correct charge.
Refrigerant line filter clogged (appears frosted). replace filter.
Irregular working of the expansion valve: check operation.
8 - THE COMPRESSOR STOPS
Faulty high pressure switch: check pressure switch calibration and operation.
1 - check clearances and make sure coils are not obstructed.
Insufficient cooling air at air-side exchanger:
2 - check fan operation.
Excessive ambient temperature: check unit operation limits.
Excessive refrigerant charge. discharge surplus refrigerant.
9 - THE COMPRESSOR IS NOISY AND VIBRATES
1 - check expansion valve operation.
2 - check superheating.
Compressor is pumping liquid, excessive refrigerant fluid in crankcase.
3 - adjust superheating, if necessary replace expansion valve.
Mechanical problems in the compressor: replace compressor
Unit running at the limit of specified conditions of use. check unit operation limits.
10 - THE COMPRESSOR RUNS CONTINUOUSLY
Excessive thermal load: check system sizing, leakage and insulation.
Working set point too low in cooling cycle (too high in heating cycle). check setting and reset.
1 - identify and eliminate any leaks;
Insufficient refrigerant charge.
2 - restore correct charge.
Refrigerant line filter clogged (appears frosted). replace filter.
Control board faulty: replace the board.
Irregular working of the expansion valve: check operation.
Compressor contactor stuck: replace contactor.
1 - check clearances and make sure coils are not obstructed.
Poor ventilation to the coil:
2 - check fan operation.
11 - THE FAN DOES NOT WORK OR STARTS AND STOPS
1 - check for short-circuits
Thermal protection activated:
2 - replace motor.
12 - THE CIRCULATION PUMP DOES NOT START
Lack of voltage to the pump unit: check electrical connections.
Absence of signal from the control board: check.
Pump blocked: unblock the pump.
Pump motor failure: replace the pump.
Remote ON/OFF switch in OFF position): put in ON position.
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