29
CHA
8. TROUBLESHOOTING
PROBLEM
POSSIBLE REASONS
RECOMMENDED ACTION
I.
THE UNIT
DOESN‘T START
1. No flow-switch or differential pressure switch agreement
2. The connections are faulty or the contacts are open
3. The compressor‘s faulty
4. The external enables have not been given
5. The work probe enable has not been given
6. The antifreeze enable has not been given (+)
7. A safety device enable has not been given (+)
8. The anti-recirculation timer is active
9. The fan thermal cut-outs trip (+)
1. Give off idraulic circuit, verify the right running of pumps
and if valves are open
2. Check the phase sequence, check the voltage and close
the contacts.
3. See point II.
4. Check the water circulation pump and the differential
water pressure switch, and vent the circuit. Check further
external enables.
5. System on temperature, no cooling demand. Check
adjustment and operation.
6. Check adjustment and operation.
7. See points IV or V.
8. Wait about 5 minutes.
9. See points VI.
II.
A COMPRESSOR
DOESN‘T START
1. The compressor has blown
2. The power circuit is open
3. The motor protection is open (+)
4. The compressor contactor is disabled
1. Replace.
2. Close the compressor circuit breaker after identifying the
reason why it cut in.
3. The compressor was working in critical conditions or
there isn‘t enough refrigerant. Check the work conditions
and see point VII.
4. Check the voltage at the ends of the contactor coil and
the continuity of the coil.Replace if faulty.
III. THE
COMPRESSOR
STARTS
AND STOPS
REPEATEDLY
1. The compressor is faulty
2. The low pressure switch has cut in (+)
3. The differential oil pressure switch has cut in (+) (only for
semihermetic compressors)
4. The compressor contactor is faulty
5. The set-point values are incorrectly set
6. There‘s not enough refrigerant liquid
1. Check and replace if necessary.
2. See point V.
3. Make sure the difference in pressure between the oil
pump delivery and low pressure is greater than at least
one bar, otherwise check the oil level and top up if
necessary. Check the filter and the oil pump (replace if
faulty). Have the compressor overhauled if necessary
4. Check and replace if necessary.
5. Modify them by referring to the information shown on
the microprocessor programme.
6. See point VII.
IV.
A COMPRESSOR
DOESN‘T START
BECAUSE THE
HIGH PRESSURE
SWITCH HAS CUT
IN (+)
1. The pressure switch doesn‘t work
2. The end-of-defrosting pressure switch doesn‘t work **
3. There‘s too much refrigerant liquid
4. There‘s non condensable gas in the refrigerant circuit
5. The refrigerant filter is clogged
6. The metal filters of the condenser (if fitted) are clogged.
The air flow is too low *
7. The condenser fans do not work *
8. There‘s air in the water circuit **
9. The circulation pump is faulty **
1. Check and replace.
2. Check and replace.
3. Remove the excess refrigerant liquid from the system.
4. Drain the circuit, pressurise and recharge the unit
5. Check and replace.
6. Clean the filters with compressed air or water.
7. See point VI.
8. Vent the water circuit.
9. Check the pump and replace if necessary.
V.
A COMPRESSOR
DOESN‘T START
BECAUSE THE
LOW PRESSURE
SWITCH HAS CUT
IN (+)
1. The pressure switch doesn‘t work
2. The unit is completely empty
3. The liquid shut-off valve is not completely open
4. The thermostatic expansion valve doesn‘t work properly
5. The refrigerant filter is clogged
6. The metal filters of the evaporator (if fitted) are clogged.
The air flow is too low **
7. The evaporator fans do not work **
8. The evaporating coil is covered with frost **
9. The water circulation pump is faulty *
1. Check and replace.
2. See point VII.
3. Check and open it completely if necessary.
4. Check, clean and replace if necessary.
5. Check and replace.
6. Clean the filters with compressed air or water.
7. See point VI.
8. See point XIII.
9. Check the pump and replace if necessary
(+) The microprocessor indicates when the safety devices cut in (see attached manual).
*
Operation only during cooling cycle.
** Operation only during heating cycle.
