Chapter 8 Troubleshooting 53
Liebert.CRV+ Series Air Cooled Precision Air Conditioner User Manual
Chapter 8 Troubleshooting
This chapter introduces the troubleshooting. You can read this part by referring to the part in chapter 5 concerning the
alarms.
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 8-1, Table 8-2 and Table 8-3.
Table 8-1 The troubleshooting of fan
Symptom
Possible causes
Items to be checked or handling method
EC fan can’t be start
Power Supply
Disconnected
Check that the fan MCB is closed;
If the MCB is closed, check that the power voltage of each phase is
normal
Control board faulty
Check J15 on the micro-processing control board, judging if the
control board is faulty
Fan power module faulty
Check the alarm lamp on the fan power module, judging if it is faulty
EC fan 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 8-2 Troubleshooting of heating system
Symptom
Possible causes
Items to be checked or handling method
Heating system does not
start, the contactor does
not close
No heating demand
Check the state of the micro-processing controller, and confirm if a
heating command is required
Safety device of the
heating system is open
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
Contactor closes, but
heating is ineffective
Heater main power is off
1. Check if the heater's MCB is turned ON.
2. Check L1, L2 and L3 voltages are normal when the contactor is
energized.
Electric heater burned
Turn off the power the physically check the condition of the heater.
