36 on a Stiebel Eltron LWZ 304 SOL / LWZ 404 SOL: Min. flow rate: For 2 hours the flow rate has been < 5 l/min; electric emergency/booster heater blocked
Short answer
On a Stiebel Eltron heat pump, 36 means: Min. flow rate: For 2 hours the flow rate has been < 5 l/min; electric emergency/booster heater blocked. 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: Min. flow rate: For 2 hours the flow rate has been < 5 l/min; electric emergency/booster heater blocked.
Part involved: water flow / pump / booster heater.
When it shows: For 2 hours the flow rate has been < 5 l/min; electric emergency/booster heater blocked.
Is it safe?
| Does the heat pump stop? | Yes |
|---|---|
| Engineer needed? | Yes |
The heat pump stops until the fault clears or is reset.
Resetting itself: unknown.
Manual reset: unknown.
What you can check
- Note the fault number shown on the programming unit display.
- Check the appliance breakers/MCBs at the consumer unit are on.
What the engineer will check
- Follow remedy in LWZ 304/404 SOL installation manual section 9.4; causes largely parallel LWZ 5-8 list.
Who to ask for: Heating / heat pump engineer.
What you might notice
Sources
- INSTALLATION LWZ 304 SOL / LWZ 404 SOL (English, via ManualsLib manual 1279865) ↗ · page 44 · Reviewed 23 September 2026
A code explains what the controller detected, not a confirmed root cause.
Reviewed: 23 September 2026