Heat pumps · Error codes · Daikin
LHDaikin · Altherma HT (high temperature split)
LH on a Daikin Altherma HT: Converter Error
Short answer
On a Daikin heat pump, LH means: Converter Error. The manual does not say whether the heat pump stops. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: Converter Error.
Part involved: power supply / inverter electrical.
Likely causes:
- Inverter PC board problem.
Is it safe?
| Does the heat pump stop? | Not stated |
|---|---|
| Engineer needed? | Yes |
The manual does not say whether the heat pump stops.
Resetting itself: unknown.
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 inverter PC board problem.
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
Sources
- Service Manual Daikin ALTHERMA HT ERSQ/ERRQ 011-016 AA V1/Y1 + EKHBRD (ESIE09-08C) ↗ · ESIE09-08C · page 204 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026