Heat pumps · Error codes · Daikin
AEDaikin · Altherma HT (high temperature split)
AE on a Daikin Altherma HT: Water Circuit Error
Short answer
On a Daikin heat pump, AE means: Water Circuit 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: Water Circuit Error.
Part involved: unit.
Likely causes:
- Blocked waterflow or heat exchanger (waterside); The water circuit has a too high ESP (external static pressure).
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.
What the engineer will check
- Follow the service-manual troubleshooting flow chart for this code: check blocked waterflow or heat exchanger (waterside); check the water circuit has a too high ESP (external static pressure).
Who to ask for: Heat pump installer.
Certification: None specific.
Sources
- Service Manual Daikin ALTHERMA HT ERSQ/ERRQ 011-016 AA V1/Y1 + EKHBRD (ESIE09-08C) ↗ · ESIE09-08C · page 150 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026