Sounds like air pressure switch to me. Id go for that first before throwing a ton at a new pcb. Your air pressure switch makes once the fan starts running. This then starts the ignition sequence. If its not making, you dont get a spark. Also check for any debris in the air pressure switch hoses...
You could get one here also:
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&rd=1&item=200260216079&ssPageName=STRK:MESE:IT
It ends up being cheaper with the delivery and VAT combined.
Its quite a good little business ive got going on ebay. Some days i make more on ebay than i do going to work! The only trouble on ebay is you competing with people who work for firms and they nick stuff, list it on ebay and they dont care what price they get for is as they didnt pay for it in...
fair enough. i only set the ebay business up in february and since then, i cant believe how cheap things are when you say 'im a merchant'. Also buying in bulk saves lots aswell. I couldnt believe it.
Fot example, part 1 ball valves are what? £4-5 from merchants?
well im getting them for...
i keep mine in my garage and sell it on ebay. And the stuff i use myself, I charge the customer merchant price- so i make on the gear as well as the job. I also sell to local plumbers round my area and im cheaper than all the suppliers
get this one: Its cheaper than screwfix. I use silicone as a sealant to be sure it wont leak.
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=200262169707
You'll find one here. I know the listing says Baxi, but its the same diverter valve in the Baxi's as your Alpha, so i promise you it will fit.
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&rd=1&item=200261251399&ssPageName=STRK:MESE:IT