ERR-FLOW-RATE on a Stiebel Eltron WPM 3 heat pump manager: 5 FLOW RATE faults in 24 hours of compressor runtime
Short answer
On a Stiebel Eltron heat pump, ERR-FLOW-RATE means: 5 FLOW RATE faults in 24 hours of compressor runtime. 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: 5 FLOW RATE faults in 24 hours of compressor runtime.
Part involved: compressor / expansion valve / pressure switches.
When it shows: 5 FLOW RATE faults in 24 hours of compressor runtime.
Likely causes:
- Check flow rate; remove cause.
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 - WPM/IWS reset 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 flow rate; remove cause.
Who to ask for: F-gas/refrigeration-qualified heat pump engineer (R290/A3 flammable-refrigerant competence for R290 models).
Certification: F-gas certification for fluorinated refrigerants (R410A/R454C); flammable refrigerant (R290) handling training for R290 models.
What you might notice
Sources
- OPERATION AND INSTALLATION Heat pump manager WPM 3 (DM0000035521) ↗ · A 316199-43934-9674 · page 46 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026