i have a potterton suprima 40,been working ok then stopped working, it does not ignite the gas, it clicks trying then shuts down not certain if gas is there to ignite. press restart it will try ignite, sounds like it going to work then stops
could be your gas valve not working, best getting in touch with a local engineer to have a look. should only cost you a call out fee of around �50 to find out ,then your valve. not sure how much. try your local plumbing merchant e.g plumb centre, pts or hrpc