Gree U8 fault code

What it means

The mains zero-crossing detection circuit is not reading correctly.

Safety: Safe isolation, then TREAT THE DC LINK AS LIVE. The electrolytic capacitors hold a lethal charge after the supply is off. Discharge through a resistor across the + and − terminals (Gree specifies approx. 100 Ω 20 W) and confirm with a meter on DC before touching the board. Never short the terminals with a screwdriver.

Source: Gree (Zhuhai) Service Manual, Bora Inverter R32 §9.1 Error Code List

UK models this code applies to

Tap yours to open U8 on that machine.

U8 on these comes from each model's own manual, which may not match the meaning above — tap yours to read it.

Now the harder half: proving what caused it

U8 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.

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