Ive got the same boiler in my house,
A few months ago it had a fault where it worked fine most of the time but every now and then it wouldnt warm the water, either at the tap or on central heating. The pilot light was still on.
If I switched it off or waited a while it started working fine again.
I got a bloke out to look at it and he said if it wasnt doing it when he was there he would struggle to diagnose it (fair point) but he guessed at it being the circuit board (PCB).
So I managed to get one from ebay, brand new. Fitted it myself but it didnt solve the problem. (very annoying)
I did a few fault finding bits on my own and traced the problem to the Differential pressure switch. (bit of luck involved as im no boiler engineer, but can turn my hand to most things)
I went to the parts merchants and got the part which had been modified by Vokera but it was easy to fit. The old one is a round metal unit about 3 inch in diameter and has been replaced by a plastic one.
The only thing I can assume is that the switch is electrical and was causing an intermitant fault by not switching or whatever it does.
But if you have no hot water this could be the problem.
If your wanting to try and save money and do it yourself you have to take the chance.
Robbo, December 2008
