12 on a GoodWe Technologies Co., Ltd. GoodWe ET / ET Plus+: Internal Fan Failure (Back-Up Over Load for ES) - ES: backup loads exceed max output
Short answer
On a GoodWe Technologies Co., Ltd. inverter, 12 means: Internal Fan Failure (Back-Up Over Load for ES) - ES: backup loads exceed max output. The inverter keeps running with some functions stopped. An engineer is needed to fix the cause.
Reviewed 24 September 2026 · 1 source
What it means
The manual says: Internal Fan Failure (Back-Up Over Load for ES) - ES: backup loads exceed max output.
Part involved: fan / backup output.
Likely causes:
- ES: backup loads exceed max output; internal fan blocked; fan cable loose. | Troubleshooting: Reduce backup loads; restart; contact service.
Is it safe?
| Does the inverter stop? | Partly |
|---|---|
| Severity | Fault — clears by itself when the condition goes |
| Engineer needed? | Yes |
The inverter keeps running with some functions stopped.
Resetting itself: unknown.
Manual reset: Restart per GoodWe troubleshooting guide.
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.
- On ES/EM models: switch off large appliances on the backup circuit (FAULT LED blinking once also means back-up overload - reduce load).
What the engineer will check
- Check fan and wiring; confirm backup load within rating.
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
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