heating pump

[Pol55]

Hi I am new to this site, and found it very useful but now I have a problem myself.
I have a glow worm 52b balanced flue boiler which has never given me any problems and still working well, however about three months ago the pump stopped working so I replaced the head and got it up and running again (I can still get hot water)
then two months on the pump seemed to go again, electrics going to the pump are fine, has not seized just not turning, so bench tested another pump all working, installed it, clicked programmer on heating came through rads all heated, then I switched it off at programmer when I turned it back on, pump ceased to work electrics still going through, baffled , can anyone help? or had this problem? thanks

 

[stem]

Sometimes the pump will run OK in air on a bench test but not be able to circulate water due to the extra forces involved, so it's not always a true indicator.

As the electrical supply would seem to be OK, is there a lot of black sludge in your system. This is responsible for most non electrical pump failures.

 

[Pol55]

thankyou for that stem, pump was only on for 20 mins, and when bleeding rads water is clear, did wonder if it had anything to do with the programmer not working correctly? and somehow affected the pump?
just at a loss. I bench tested pump before putting on and it worked, then when it stopped working took off and bench test again, and nothing

 

[stem]

Then you need to make sure that the pump has an electrical supply when it should be running. This can be easily checked by someone competent with a multimeter.

If it doesn't have a 230v supply when it should be running, then it may well be the controls. It could be the programmer, the thermostat, motorised valve, or even the boiler PCB it it controls the pump. It all depends upon the type of system you have.

 

[Pol55]

thankyou again, someone did come out and checked it all, all seemed to be fine except the pump so replaced it but did wonder about the boiler PCB will get it all checked again thankyou so much for your time, will let you know the outcome