LG Therma V CH20 fault code

What it means

Electric heater overheated (thermal cut-out / fuse blown)

The electric heater's thermal cut-out has tripped and blown its fuse — almost always low water flow or air across the heater, not the element itself.

Safety: Safe isolation before working on the heater — it runs at mains voltage.

UK models this code applies to

From the LG service literature we hold (LG AWHP Service Manual MFL68682007 (© 2020, R32 Therma V) — error codes + component tables; scope: code SET & fan figure whole-range, compressor winding confirmed 12/14/16 kW, thermistor tables part-level) — not a scraped list.

Now the harder half: proving what caused it

CH20 names a symptom, not a root cause. In the app, the same code opens a guided investigation: what to measure first, the expected values for your exact model, and an honest verdict — including “nothing in this machine is broken” when that's what the readings say.