18x75 on a SolarEdge HD-Wave single-phase inverter: Temperature Too High: Over temperature
Short answer
On a SolarEdge inverter, 18x75 means: Temperature Too High: Over temperature. The inverter keeps running with some functions stopped.
Reviewed 24 September 2026 · 1 source
What it means
The manual says: Temperature Too High: Over temperature.
Part involved: Heatsink / internal temperature.
Likely causes:
- Insufficient clearances.
- Dirty/obstructed heat-sink fins.
- High ambient temperature.
Is it safe?
| Does the inverter stop? | Partly |
|---|---|
| Severity | Fault — clears by itself when the condition goes |
The inverter keeps running with some functions stopped.
Resetting itself: yes - derates or stops and restarts when cooled.
Manual reset: no.
What you can check
- Read and note the exact code and time from the inverter display or app (screenshot).
- Check nothing is covering or stacked against the inverter and the cooling fins are not blocked (look only).
- Note if it is in direct afternoon sun or a hot loft.
- If the code persists, contact the installer. SolarEdge's list says 'OFF/ON to reconnect' for some codes - that means the inverter's own ON/OFF switch; only use it if your installer has shown you how. Never open the inverter or touch DC cables/connectors.
What the engineer will check
- Check clearances per manual.
- Clean heatsink/fans.
- Check fan operation.
- Consider relocation or shading.
Who to ask for: PV installer.
Certification: Electrician competent in grid-connected PV (BS 7671 Section 712; IET Code of Practice for Grid-connected Solar PV), ideally the original MCS-certified PV installer; brand-approved/trained installer to keep manufacturer warranty.
What you might notice
Sources
- Troubleshooting SolarEdge Systems, Addendum (Europe & APAC) MAN-01-00333-1.2 ↗ · MAN-01-00333-1.2 · page PDF p.3 · Reviewed 24 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 24 September 2026