17 on a GoodWe Technologies Co., Ltd. GoodWe ET / ET Plus+: Vac Failure - Grid power failure

What it means

The manual says: Vac Failure - Grid power failure.

Part involved: grid connection.

Likely causes:

• Grid power failure; AC not connected well; AC breaker fails; grid not connected. | Troubleshooting: Make sure grid power available; check AC terminal voltage and terminations; check AC breaker and L/N connection; turn AC breaker off and on again after 5 minutes.

Is it safe?

The inverter stops until the fault clears or is reset.

Resetting itself: yes.

Manual reset: Automatic when condition clears.

What you can check

• Check the inverter LEDs (FAULT LED on = fault) and read the alarm in the SEMS Portal app or SolarGo app; note code, message and time for your installer.
• Check for a power cut in your area.
• Check the inverter's AC breaker in the consumer unit is on (GoodWe: 'Make sure grid is connected and AC breaker turned ON').
• GoodWe's final step is to turn the AC breaker off and on again after 5 minutes - you can do this at the consumer unit.

What the engineer will check

• Measure AC terminal voltage, check terminations along AC path, L/N polarity, breaker function.

Who to ask for: GoodWe-trained installer / MCS PV & battery installer.

Certification: Qualified electrician (BS 7671; MCS-certified PV installer for work on the PV array/DC side).

What you might notice

• Error code shown on inverter or app
• Solar panels not generating at all
• Inverter shown offline / not reporting in the app

Sources

• Troubleshooting Guide Hybrid Inverter (ET, ET PLUS+, EH, ESA, ES, EM, EHB, ES G2; BT, BH, BP, SBP) - EMEA ↗ · V1.0-2023-03-10 · page 15 · Reviewed 24 September 2026

A code explains what the controller detected, not a confirmed root cause.

Reviewed: 24 September 2026