Heat pumps · Error codes · Stiebel Eltron
8177Stiebel Eltron · WPM 3 heat pump manager (older controller)
8177 on a Stiebel Eltron WPM 3 heat pump manager: Evaporator cannot dissipate enough heat in cooling mode
Short answer
On a Stiebel Eltron heat pump, 8177 means: Evaporator cannot dissipate enough heat in cooling mode. 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: Evaporator cannot dissipate enough heat in cooling mode.
Part involved: unspecified.
When it shows: Evaporator cannot dissipate enough heat in cooling mode.
Likely causes:
- Clean the evaporator.
Is it safe?
| Does the heat pump stop? | Yes |
|---|---|
| Severity | Fault — clears by itself when the condition goes |
| Engineer needed? | Yes |
The heat pump stops until the fault clears or is reset.
Resetting itself: yes - restarts after IWS fault time/idle time.
Manual reset: after 5 faults in 2 h run: IWS reset.
What you can check
- Read and note the full message code and time from the WPM display (DIAGNOSIS / NOTIFICATIONLIST if accessible without a code).
- Check the heat pump and controller circuit breakers/isolators at the consumer unit are on.
- Check the outdoor unit air intake/discharge is not blocked by leaves, snow or ice (air source units).
What the engineer will check
- Clean the evaporator.
Who to ask for: Heating / heat pump engineer.
What you might notice
Sources
- OPERATION AND INSTALLATION Heat pump manager WPM 3 (DM0000035521) ↗ · A 316199-43934-9674 · page 52 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026