Potterton Suprima 100

[Mikeallthumbs]

Have a Potterton Suprima 100 (AHHV 748 0217, GC 41-607-82) installed about 10 years ago. HW is working fine, but not the CH. Have bled all radiators, so confident no air lock. Have tried restarting system at control panel, but that makes no difference. Basically, the gas comes on, ignites no problem, but goes off after a minute or so. The pump in the airing cupboard is working, in tune with the timeclock.
Could this be sludge build up in the heat exchanger preventing circulation of water, or a valve not opening up in the boiler?
Any suggestions please! Am in Marlow Bucks, is this something I could easily repair/replace, and can anyone recommend a local competent plumber please.
Thanks.

 

[gas4you]

If it's working ok for HW then I doubt it's a boiler problem.

Check the zone valve for the heating circuit hasn't stuck shut, therefore not letting any flow through the system when on ch only.

 

[Mikeallthumbs]

If it's working ok for HW then I doubt it's a boiler problem.

Check the zone valve for the heating circuit hasn't stuck shut, therefore not letting any flow through the system when on ch only.

Thanks Dave, I bled the pump (following instructions elsewhere on here, and at same time I tried manually opening and then closing the zone valve (returned it to auto), started up the system, and..... it seems to be back to normal so far.....

We'll see how it is in the morning, but thank you for your advice. Certainly wasn't the boiler which was my main worry! (£££)