IE21 on a SolaX Power SolaX X1-Hybrid G4: Low TempFault - low temperature fault
Short answer
On a SolaX Power inverter, IE21 means: Low TempFault - low temperature fault. The inverter stops until the fault clears or is reset.
Reviewed 24 September 2026 · 1 source
What it means
The manual says: Low TempFault - low temperature fault.
Part involved: Low ambient temperature.
Likely causes:
- Ambient temperature too low.
Is it safe?
| Does the inverter stop? | Yes |
|---|---|
| Severity | Fault — clears by itself when the condition goes |
The inverter stops until the fault clears or is reset.
Resetting itself: yes - when temperature rises.
Manual reset: no.
What you can check
- Read and note the exact code and time from the inverter display or app (screenshot).
- Usually clears as the location warms; note the location (garage/outbuilding).
- Where the SolaX manual says 'press the ESC key to restart the inverter', a homeowner can do that on the display. Steps that say 'disconnect PV+/PV-/battery' are for the installer only.
What the engineer will check
- Check location against operating range.
- Consider relocation.
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
- X1-Hybrid-G4 3.0/3.7/5.0/6.0/7.5 kW User Manual Version 3.0 (Version 03, 2024-08-08), doc 320101081103 ↗ · 3.0 · page PDF p.124 · Reviewed 24 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 24 September 2026