Grunfos central heating pump

diamond_dave

Pump stuck after being left off. Stripped it down then cleaned and eased the seized impeller so thought all was a goer. However, on switching on - nothing. What can cause this? Any suggestions? Does it have a capacitor or internal fuse. I checked windings for continuity and all seemed ok. Baffling.

Keep_pedalling

It’s knackered time for a replacement.

ThisIsWeird

Have you tried the motor with its own supply?
I've no idea what's inside them electronically, but I'd imagine 'yes' to a cap, but no to a fuse.
You are certain it's receiving power?
Isn't the electrical section openupable too?
If you need to replace, then the new range of 'smart' pumps - which automatically adjust flow to actual need - are so much quieter, and use far less power 

nofoollikeold

1. It will have a start / run capacitor.  Usually around 8 microfarads but must be mains AC rated (around 350 to 400V, NOT 240V).
2. If you wire it to a normal plug and plug it in for a short period (max. 2 minutes), then:
2.1 If it hums and gets hot, but the impeller doesn't turn, likely to be the capacitor.
2.2 If it makes no sound, likely to be the windings and new pump required.
3. Personally I'd avoid smart pumps, more to go wrong, even if they save a bit of electricity.