Chapter 8 Troubleshooting - Emerson Liebert.CRV+ Series 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.
Symptom
EC fan can't be start
Symptom
Heating system does not
start, the contactor does
not close
Contactor closes, but
heating is ineffective
Liebert.CRV+ Series Air Cooled Precision Air Conditioner User Manual
Table 8-1 The troubleshooting of fan
Possible causes
Check that the fan MCB is closed;
Power Supply
If the MCB is closed, check that the power voltage of each phase is
Disconnected
normal
Check J15 on the micro-processing control board, judging if the
Control board faulty
control board is faulty
Fan power module 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;
EC fan faulty
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
Possible causes
Check the state of the micro-processing controller, and confirm if a
No heating demand
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
Safety device of the
the safety device may be open. Then check if the fuse is open and if
heating system is open
the temperature controller is damaged. Measure the resistance of the
heater with an ohmmeter to judge if the heater is damaged
1. Check if the heater's MCB is turned ON.
Heater main power is off 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.
Chapter 8 Troubleshooting
Items to be checked or handling method
Items to be checked or handling method
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