CH pump screaming question

[dal5band]

I did some work on replacing a couple of radiator valves, filled the system, bled the radiators and everything ran fine for a day. Today, the pump screamed / screeched for about a minute before I turned it off. I banged the pump and bled the end screw and it returned to normal operation. I persume it was an air pocket working its way through the system.

Will this have damaged the pump much ? seems ok at the moment.

 

[Diyisfun]

Pump should be ok, but you can get a lot of air coming out of it

 

[dal5band]

Thanks - pure luck the pump is in the kitchen boiler cupboard so we heard it straight away, probably would have burnt out otherwise.

 

[ChrisR]

I once had a (loft boiler) system drain empty due to a leak. The pump screamed for an hour before it was turned off. The pump lasted at least a couple of years, (then I lost contact with the installation.) It was a Wilo pump too, not supposed to be the best. Feel lucky??

 

[dal5band]

That's funny - mine's a Wilo as well !! If you look at it closely it seems to be the same as the grundfos - these days they are probably all made at the same Chinese factory !!