Potterton Puma 100e DHW but no CH

[spaglemon]

Have searched for similar threads and although there are many the majority seem to be that their heating comes on briefly at least, my hot water is fine but when I try to get heating there's no ignition at all, the only activity I can hear is the pump but it seems a bit louder than usual and has a slightly high pitched whine that I can't say I've noticed before ? it may just sound louder because the rest of the boiler isn't working though.
I replaced the pump around 2 years ago, I also replaced the diverter valve probably approx 4 years ago.
Any suggestions at all ?

Thanks

 

[ianmcd]

do you have a dripping hot water tap ?

 

[spaglemon]

No but thanks for the reply

 

[spaglemon]

Small update. Got in from work and for some reason decided to try the heating while the boiler was cold, it fired up straight away but went off within 30 or so seconds. Hadn't noticed this before as the boiler's rarely stone cold what with running hot water.
Does this make it sound like the diverter again ?

Thanks

 

[Agile]

It could well be.

Particularly if the system is dirty.

Tony7

 

[spaglemon]

I think I've fixed it, I have an identical boiler that has lots of newer parts on it, I took the wax capsule out of the other one and fitted it to my boiler, It made no difference. I had an issue with the main pcb some years ago and managed to fix it, the spare boiler had a new pcb fitted so I swapped them out and hey presto it's working perfectly for now.
Thanks