LG CH21

Critical

Multi V5 — Outdoor unit inverter board IPM fault error (Master: 211, Slave 1: 212, Slave 2: 213).

LG CH21: Outdoor unit inverter board IPM fault error (Master: 211, Slave 1: 212, Slave 2: 213). This fault typically halts operation and needs immediate attention.

Possible causes

Compressor damaged, disconnected, or its winding insulation has failed
IPM module on the inverter board damaged, or input voltage too low, causing overcurrent detected by CT sensor on U-V-W phases

Check steps

Verify all electrical wiring connections and measure resistance/insulation between compressor phases
Inspect compressor and DC link wiring, check IPM heat sink connection, and test the inverter PCB assembly

Affected parts

Compressor
Inverter PCB (IPM module)
CT sensor
Wiring harness

Safety note

High voltage — disconnect power supply and allow capacitors to discharge before working on the inverter.

Source: LG resmi servis kilavuzu (bagimsiz cift-dogrulandi) — LG Multi V5 Service Manual (ManualsLib doc #1483751), p.144, "Error No. 21" bölümü: "Outdoor unit inverter board IPM fault error" — Master: 211, Slave 1: 212, Slave 2: 213 (nomenklatür kuralı p.126: sağdaki rakam ODU çerçevesini gösterir, 1=Master, 2=Slave1, 3=Slave2). Bağımsız çapraz kontrol: techfaultfix.com, jus…

Reviewed by Anıl Güzeldemir — in the refrigeration machine room since 2006, developer of Enthalio.

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