50496 on a Stiebel Eltron WPM heat pump manager / WPMsystem: Diverter valve has not switched. It is not possible to operate the heat pump in reverse mode
Short answer
On a Stiebel Eltron heat pump, 50496 means: Diverter valve has not switched. It is not possible to operate the heat pump in reverse 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: Diverter valve has not switched. It is not possible to operate the heat pump in reverse mode.
Part involved: water flow / pump / booster heater.
When it shows: Diverter valve has not switched. It is not possible to operate the heat pump in reverse mode.
Likely causes:
- Check leads and the relevant plug-in connectors, and replace if faulty.
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: no.
Manual reset: yes - reset of heat pump via WPM after cause removed (contractor).
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
- Check leads and the relevant plug-in connectors, and replace if faulty.
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 26 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026