Heat not getting past circulating pump

[HammerandTongs]

Hi guys,

Potterton 50 gas boiler, sealed system, central heating and hot water cylinder. Timer controlled.

Had to shut the electric off to fix a motorised valve. Afterwards found the pressure was zero, and no hot water flowing past the circulator pump.

Filled the system back up to around 1 bar, bled off air from both the circulator pump and an air release above the boiler. Tried bleeding the radiators but just cold water.

Circulator pump heats up, but nothing downstream.

Any ideas?

 

[dcawkwell]

Remove central screw of the pump.
Is it spinning?

 

[HammerandTongs]

It hadn't been when I last tried (rotated reasonably freely), but I gave it a good spin with my fingers and it just kept on going! Pipes seem to be warming, could be good!

 

[matt1e]

you need to replace the pump Capacitor as it is as we say, goosed

Matt

 

[Bunnyman]

U need a new pump the capacitor is knackered. The capacitor gives the pump a kick to start it, then the motor keeps it spinning, u have started it manually, it will probably fail when it cools down .

 

[matt1e]

U need a new pump the capacitor is knackered. The capacitor gives the pump a kick to start it, then the motor keeps it spinning, u have started it manually, it will probably fail when it cools down .

No, he needs a new capacitor to put in the pump - much cheaper than a new pump

 

[HammerandTongs]

My short-lived joy was limited. It actually stops after about 5-10 seconds. Can re-start it each time, but stops pretty quickly. Blockage?

 

[Bunnyman]

Are you reading the posts mate??? Yea change the capacitor it will last about a month

 

[matt1e]

My short-lived joy was limited. It actually stops after about 5-10 seconds. Can re-start it each time, but stops pretty quickly. Blockage?

No

Still the Cap...........probably

 

[HammerandTongs]

Cheers all. I'll try switching out the capacitor, failing that new pump I guess.

 

[HammerandTongs]

Just tried turning the central heating motorised zone valve to 'flushing' and now the circulator pump spins fine and stays on. What the hell?