Troubleshooting
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7 Troubleshooting
Troubleshooting is to be performed by the trained and qualified service personnel. However, the checklists have been
provided just for reference purposes.
• Prior to troubleshooting, the lethal voltage may be present in the unit which can be fatal. All notes,
warnings, and cautions marked on the unit as well as the ones mentioned in the manual must be
considered, otherwise, it may lead to injury and fatality.
• Extreme care and caution is required while troubleshooting on-line.
Note1: Qualified and professional maintenance personnel are the one supposed to troubleshoot and handle the unit.
Note2: If jumpers are used for troubleshooting, remember to remove the jumpers after the troubleshooting, failing to
remove connected jumpers may bypass certain control functions and increase the risk to the unit.
7.1. Troubleshooting and Fault Handling of EC Fan
The troubleshooting of EC fan is explained in the
.
Table 7-1 Troubleshooting of the Key Components of the EC Fan
Symptom
Possible Causes
Items to be Checked or Handling Method
EC fan cannot start
MCB trip
Check whether the fan circuit breaker is closed properly.
Fan power module
failure
Check the alarm light of the fan power module to determine
whether there is a fault.
Cabling/wiring
failure
Check whether the cables from the main control board, fan fault
detection board, and power module to the control terminal block
are correctly connected.
7.2. Troubleshooting and Fault Handling of Electronic Expansion Valve
The Electronic Expansion Valve (EEV)is a key component that adjusts system refrigerant and cooling capacity. Thus, its
normal operation is very important. The troubleshooting of EEV is explained in the
Table 7-2 Troubleshooting of the Key Components of the EEV
Symptom
Possible Causes
Items to be Checked or Handling Method
Electronic
expansion valve
adjustment failure
Temperature
sensor, pressure
sensor failure
Check whether the sensor wiring is loose.
Check whether the sensor wiring position on the control board is
correct.
Control board
power down
Check whether the transformer output fuse is burned out.
Check whether the input power of the electronic expansion valve
control board has 24 V power supply.
Control board
cabling/wiring
Check the valve body wiring on the electronic expansion valve
control board for errors; Check whether the communication cable
between the electronic expansion valve control board and the main
control board is cabled incorrectly.
