Central heating not working Baxi pfl 50

[neggiem01]

Hi, my central heating has stopped working and I could use some advice. Not sure if its related, but had a broken bath mixer tap which meant I had to cap off both pipes to it. Few days later, got cold and so started off the central heating for the first time this year. Heard the boiler start and the lights went o.n. Lots of loud banging from pipes and no heat to radiators/ no hot water. Checked there was water in two tanks in loft. OK. Checked pump running. Can hear pump. Attempted to bleed radiator nearest to storage tank, air hissing but not water. Checked all other radiators and got water as soon as i turn key. But no heat to any of them. Left it for a while, after 10 minutes hear bioler kicking in again. Lots of banging, little heat to the left hand side of the rad, turned the key to bleed and lots of air but still no water.
Have searched forums on noisy pipes, bleeding radiators etc but not found anything similar. Boiler does not have a pressure gauge so don't know how to check it? Any thoughts/advice most welcome. N

 

[Nixt]

Try bleeding with heating switched off, if you hear air, water will follow as it is that which forces the air out.

 

[gas4you]

Pump knackered even though you can hear it 'spinning'

 

[neggiem01]

Thanks for the quick responses...


NIxt - have tried with heating off. Still no water but no air hissing either

Dave (gasforyou) Hope not! Any other test I can do to confirm. Its a Grudfos Type UPS 15-50 if that means anything.


If I feel the pipes either side of the pump they are both hot. Would the clanging be because of the pump not working?

 

[gas4you]

banging noises as a general rule are caused by lack of circulation, which is why I suggested the pump. Other possibilities could be no bypass and zone valves stuck

 

[neggiem01]

banging noises as a general rule are caused by lack of circulation, which is why I suggested the pump. Other possibilities could be no bypass and zone valves stuck

Sorry Dave, I have no idea what "no bypass" is. I have A GREY/SILVER box to the right of the pump, this has settings for auto, and man and a lever between them. I think this is my motorised zone valve (having searched this site and google) have now pushed the lever to manual to see if it makes a difference. But so far not yet.