Carrier 38MBRQ36A-3 - IPM Malfunction or Over-strong Current Protection Diagnosis and Solution (PO)

38MBR: Service Manual
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
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IPM Malfunction or IGBT Over-strong Current Protection Diagnosis and Solution (PO)
Troubleshooting
NOTE: In figures 23-24 the following is observed:
• U,V,W references the compressor connection point
• P references input voltage
• N references output voltage
Error Code PO
Malfunction decision conditions
When the voltage signal that IPM sends to the compressor drive chip is abnormal, the LED displays “PO”
and the AC turns off.
Supposed Causes
•Wiring mistake
• IPM malfunction
• Outdoor fan assembly faulty
• Compressor malfunction
• Outdoor PCB faulty
Check the wiring between
the main PCB and the compressor.
Is there an error?
Check the IPM.
Is it in working order?
No
Yes
Check the outdoor fan and
ƚŚĞŽƵƚĚŽŽƌƵŶŝƚǀĞŶƟůĂƟŽŶ
Are they in working order?
Yes
ŚĞĐŬƚŚĞĐŽŵƉƌĞƐƐŽƌƌĞƐŝƐƚĂŶĐĞǀĂůƵĞƐ
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ZĞƉůĂĐĞƚŚĞŽƵƚĚŽŽƌŵĂŝŶW
Yes
ŶƐƵƌĞĂƉƌŽƉĞƌĐŽŶŶĞĐƟŽŶŽƌ
ƌĞƉůĂĐĞƚŚĞǁŝƌĞƐĂŶĚĐŽŶŶĞĐƚŽƌƐ
Yes
ZĞƉůĂĐĞƚŚĞ/WDďŽĂƌĚŽƌƌĞƉůĂĐĞƚŚĞŵĂŝŶW
No
WůĞĂƐĞƌĞĨĞƌƚŽƚŚĞ
&ĂŶ^ƉĞĞĚŝƐŽƵƚŽĨĐŽŶƚƌŽůŵĂůĨƵŶĐƟŽŶ
ƐŽůƵƟŽŶ
No
ZĞƉůĂĐĞƚŚĞĐŽŵƉƌĞƐƐŽƌ
No