Heat pumps · Error codes · Stiebel Eltron
30479Stiebel Eltron · WPM heat pump manager / WPMsystem (controller platform)
30479 on a Stiebel Eltron WPM heat pump manager / WPMsystem: Minimum water flow rate for activating auxiliary heater not reached
Short answer
On a Stiebel Eltron heat pump, 30479 means: Minimum water flow rate for activating auxiliary heater not reached. The heat pump keeps running with some functions stopped. An engineer is needed to fix the cause.
Reviewed 23 September 2026 · 1 source
What it means
The manual says: Minimum water flow rate for activating auxiliary heater not reached.
Part involved: water flow / pump / booster heater.
When it shows: Minimum water flow rate for activating auxiliary heater not reached.
Likely causes:
- Faulty pump. Heating circuit not sufficiently open.
Is it safe?
| Does the heat pump stop? | Partly |
|---|---|
| Severity | Warning |
| Engineer needed? | Yes |
The heat pump keeps running with some functions stopped.
Resetting itself: unknown.
Manual reset: unknown.
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 heating system pressure gauge reading is in the normal range stated by your installer.
- Check the outdoor unit air intake/discharge is not blocked by leaves, snow or ice (air source units).
What the engineer will check
- Faulty pump. Heating circuit not sufficiently open.
Who to ask for: Heating / heat pump engineer.
What you might notice
Sources
- WPM notification list (WPM V2.9) - multilingual; English section pp.15-26 (DOC-00081866) ↗ · WPM V2.9 · page 25 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026