Century COMFORT-AIRE VMH-SG Series Service Manual page 102

TS09-S: IPM malfunction or IGBT over-strong current protection diagnosis and solution
Description: When the voltage signal the IPM sends to the compressor drive chip is abnormal, the LED displays the
failure code and the AC turns off.
Recommended parts to prepare:
• Connection wires
• IPM module board
• Outdoor fan assembly
• Compressor
• Outdoor PCB
Troubleshooting and repair:
Check the wiring between
Check the wiring between
PCB and compressor.
PCB and compressor.
Does an error exist?
Does an error exist?
Check if the IPM
Check if the IPM
installed correctly.
installed correctly.
IPM continuity check
IPM continuity check
Are the IPM terminal
Are the IPM terminal
resistance uniform?
resistance uniform?
Check the outdoor fan and the
Check the outdoor fan and the
outdoor unit ventilation.
outdoor unit ventilation.
Is it in working order?
Is it in working order?
Check the compressor
Check the compressor
resistance values.
resistance values.
Are they uniform?
Are they uniform?
Replace the outdoor PCB.
Replace the outdoor PCB.
YES
NO
NO
YES
YES
NO
YES
YES
Troubleshooting
 Troubleshooting
Ensure proper connections or
Ensure proper connections or
replace the wires and connectors.
replace the wires and connectors.
Correct the installation, tighten the
Correct the installation, tighten the
screws and apply silicon grease
screws and apply silicon grease
Replace the IPM board or
Replace the IPM board or
NO
replace the outdoor PCB.
replace the outdoor PCB.
Please refer to the solution of the " fan
Please refer to the solution of the " fan
speed is operating outside of the normal
speed is operating outside of the normal
range"malfunction.
range"malfunction.
NO Replace the compressor.
Replace the compressor.

Service Manual - VMHxxSG