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 tank causing insufficient supply
4. Incorrect outlet height causing hot-water-only delivery
5. Outlet positioned below mains inlet causing air ingress
6. Undersized pipework
7. Pipes routed under floor causing air traps
8. Other outlets fitted in inlet pipes
9. Shared (non-dedicated) hot/cold supplies
10. Blanked-off pipes
11. Restrictions in flexible hoses
12. Unsecured pipework
13. Direct mains connection causing pressure issues or pump damage
14. Jointing compounds/tape causing blockage or leaks
15. Shared supply pipe causing air ingress or reduced flow
16. Missing surrey flange causing air in hot water supply
17. Leaks due to insufficient hose insertion depth
18. Debris ingress into pump causing blockage or damage if strainer omitted
19. Solder joint heat damaging plastic pump components
20. Air pockets from incorrectly routed pipework
21. Restricted or kinked flexible hoses
22. Additional outlet fittings on inlet pipework causing incorrect flow switch operation

Where to start

1. Check tank capacity is at least 227 litres (50 gallons)
2. Measure height difference between cold-water outlet and hot-water cylinder supply
3. Check position of outlets relative to mains inlet in tank