E8 on a Daikin Altherma LT: Input over current
Short answer
On a Daikin heat pump, E8 means: Input over current. The heat pump stops until the fault clears or is reset. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: Input over current.
Part involved: power supply / inverter electrical.
When it shows: ■ The following CT input with the compressor running continues for 2.5 seconds. CT input: Above 20 A ■ The system will be shut down if the error occurs 16 times. ■ Clearing condition: Continuous run for about 5 minutes (normal) | The following CT input with the compressor running continues for 2.5 seconds. CT input: Above 20 A The system will be shut down if the error occurs 16 times. 3 3 Clearing condition: Continuous run for about 5 minutes (normal).
Likely causes:
- Over-current due to compressor failure; Over-current due to defective power transistor; Over-current due to defective inverter main circuit electrolytic capacitor; Over-current due to defective outdoor unit PCB; Error detection due to outdoor unit PCB; Over-current due to short-circuit.
Is it safe?
| Does the heat pump stop? | Yes |
|---|---|
| Severity | Fault — needs a manual reset once the cause is fixed |
| Engineer needed? | Yes |
The heat pump stops until the fault clears or is reset.
Resetting itself: unknown.
Manual reset: Reset via the remote controller (Inspection/Test button) after the cause is fixed; some codes need a manual reset of the remote-controller memory (service manual section 1.4).
What you can check
- Read the full error code shown on the user interface and note it, with the date/time, for your installer.
- Check the heat pump isolator switch(es) and the consumer-unit breaker/RCD for the heat pump are ON. If a breaker or RCD has tripped, do not keep resetting it - leave it and call an engineer.
What the engineer will check
- Follow the service-manual troubleshooting flow chart for this code: check over-current due to compressor failure; check over-current due to defective power transistor; check over-current due to defective inverter main circuit electrolytic capacitor; check over-current due to defective outdoor unit PCB; check error detection due to outdoor unit PCB; check over-current due to short-circuit.
Who to ask for: Heat pump engineer / qualified electrician.
Certification: Electrical competence to BS 7671 (Part P where applicable) for mains supply work.
What you might notice
What owners and engineers report
2 owner and engineer reports mention this.
- No heating on the Altherma LT (low temperature split): 1 report
- Heat pump will not start on the Altherma LT (low temperature split): 1 report
Sources
- Service Manual ALTHERMA ERHQ006~008BAV3 / ERLQ006~008BAV3(9) / EKHBH(X)008BA (ESIE10-02) ↗ · ESIE10-02 · page 163 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026