Grundfos STP 2 fault 2

What it means

Pump runs but does not deliver water on positive pressure pumps.

Likely causes

1. İzolasyon vanaları kapalıdır (Isolation valves closed)
2. Filtreler tıkalı (Filters blocked)
3. Undersized pipework
4. Pipes routed under floor causing air traps
5. Other outlets fitted in inlet pipes
6. Shared (non-dedicated) hot/cold supplies
7. Blanked-off pipes
8. Restrictions in flexible hoses
9. Unsecured pipework
10. Debris ingress into pump causing blockage or damage if strainer omitted

Where to start

1. Check pipe diameter is 22 mm to and from pump
2. Check expansion pipe from cylinder rises to prevent trapped air
3. Check outlet pipe to shower valve rises where possible