Chapter 7 Troubleshooting - Liebert CRV+ Series User Manual

Chapter 7 Troubleshooting

This chapter introduces the troubleshooting. You can read this part by referring to the part concerning the alarms.
Warning
Certain circuits carry lethal voltages. Only professional technicians are allowed to maintain the machine. Extra care should be
taken when troubleshooting online.
Note
If jumpers are used for troubleshooting, remember to remove the jumpers after the troubleshooting, or the connected jumpers
may bypass certain control function and become a potential risk to the equipment.
The troubleshooting of components is listed in Table 7-1 ~ Table 7-3.
Symptom Possible causes
Fan power faulty
Control board faulty
Fan power module faulty
EC fan does
not start
EC fan faulty
Symptom
Heating system does not
start, the contactor does
not close
Contactor closes, but
heating is ineffective
Table 7-1 Fan fault removal
Check that the fan MCB is closed;
If the MCB is closed, check that the power voltage of each phase is normal
Check J15 on the micro-processing control board, judging if the control board is
faulty
Check the alarm lamp on the fan power module, judging if it is faulty
1. Check L1, L2 and L3 of the fan against power failure, phase loss and low voltage;
2. Check that the analog output is within the required range of 0 ~ 10Vdc;
3. Check if the motor is clogged (due to large current);
4. Check if the motor is too hot;
5. Hall failure.
If the previous three problems occur, the motor can restore normal operation after
the faults are cleared.
If the motor is too hot, you need to cut off the fan power, after the motor is cooled,
you can power on it again for recovery;
If hall failure occurs, the factory service is required
Table 7-2 Troubleshooting of heating system
Possible causes
No heating demand
Safety device of the
heating system is open
Heater main power is off
Electric heater burned
Liebert CRV+ Series Air Conditioner User Manual
Chapter 7 Troubleshooting
Items to be checked or handling method
Items to be checked or handling method
Check the state of the micro-processing controller, and confirm if a
heating command is required
Use a multimeter to measure the resistance on both ends of the
temperature controller, if the resistance is very large, it indicates that
the safety device may be open. Then check if the fuse is open and if
the temperature controller is damaged. Measure the resistance of the
heater with an ohmmeter to judge if the heater is damaged
Check that the heating MCB is closed;
If the heating contactor is closed, check if the power voltage of
contactor L1, L2, L3 is normal
Cut off the power supply and measure the resistance of the heater
with an ohmmeter to judge if the heater is damaged
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