II.13 CHECK-LIST
1 - OUTLET PRESSURE HIGH
Insufficient cooling air at air-side exchanger:
Fan does not run:
Excessive refrigerant charge:
2 - OUTLET PRESSURE LOW
Insufficient refrigerant charge:
Mechanical problems in the compressor:
3 - INLET PRESSURE HIGH
Excessive thermal load:
Irregular expansion valve operation:
Mechanical problems in the compressor:
4 - INLET PRESSURE LOW
Insufficient refrigerant charge:
Filter partially obstructed (appears frosted):
Irregular expansion valve operation:
Presence of air in the water system:
Insufficient water flow:
5 - THE COMPRESSOR DOES NOT START
Microprocessor board alarm:
No voltage, switch open:
Overload protection triggered:
No request for cooling with user system set point correct:
Working set point too high:
Defective contactors:
Compressor motor failure:
6 - THE COMPRESSOR MAKES A BUZZING NOISE
Incorrect power supply voltage:
Compressor contactor stuck:
Mechanical problems in the compressor:
7 - THE COMPRESSOR STARTS AND STOPS
Faulty low pressure switch:
Insufficient refrigerant charge:
Refrigerant line filter clogged (appears frosted):
Irregular working of the expansion valve:
8 - THE COMPRESSOR STOPS
Faulty high pressure switch:
Insufficient cooling air at air-side exchanger:
Excessive ambient temperature:
Excessive refrigerant charge:
9 - THE COMPRESSOR IS NOISY AND VIBRATES
The compressor is pumping liquid, excessive increase of coolant in sump:
Mechanical problems in the compressor:
Unit running in limit conditions:
10 - THE COMPRESSOR RUNS CONTINUOUSLY
Excessive thermal load:
Working set point too low in cooling cycle (too high in heating cycle):
Insufficient refrigerant charge:
Refrigerant line filter clogged (appears frosted):
Control board faulty:
Irregular working of the expansion valve:
Compressor contactor stuck:
Poor ventilation to the coil:
11 - THE FAN DOES NOT WORK OR STARTS AND STOPS
Thermal protection activated:
12 - THE CIRCULATION PUMP DOES NOT START
Lack of voltage in the pumping system:
Pump blocked:
Pump motor failure:
Remote ON/OFF switch in OFF position):
PROBLEM
SECTION II: INSTALLATION AND MAINTENANCE
RECOMMENDED ACTION
check clearances and make sure coils are not obstructed.
check fan operation.
drain the excess.
1 - identify and eliminate any leaks;
2 - restore correct charge.
replace compressor.
check system sizing, infiltrations and insulation.
check operation.
replace compressor.
1 - identify and eliminate any leaks;
2 - restore correct charge.
replace filter.
check operation.
bleed the water system.
check circulation pump operation.
identify alarm and take appropriate action.
close the switch.
1 - restore the switch;
2 - check the unit at start up.
check and if necessary wait for cooling request.
check and if necessary readjust set point.
replace contactor.
check for short circuit.
check voltage, investigate causes.
replace contactor.
replace compressor.
check pressure switch calibration and operation.
1 - identify and eliminate any leaks;
2 - restore correct charge.
replace filter.
check operation.
check pressure switch calibration and operation.
1 - check clearances and make sure coils are not obstructed;
2 - check fan operation.
check unit operation limits.
discharge surplus refrigerant.
1 - check expansion valve operation;
2 - check superheating;
3 - adjust superheating, if necessary replace expansion valve.
replace compressor.
check unit operation limits.
check system sizing, leakage and insulation.
check setting and reset.
1 - identify and eliminate any leaks;
2 - restore correct charge.
replace filter.
replace the board.
check operation.
replace contactor.
1 - check clearances and make sure coils are not obstructed;
2 - check fan operation.
1 - check for short-circuits;
2 - replace fan.
check electrical connections.
unblock the pump.
replace the pump.
put in ON position.
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