Cheers
Had a new pcb fitted 3-4 yrs ago.
Sought advice from potterton helpline, they asked for a corgi no. (Which I didn`t have, but after a bit of pleading about not wanting to be ripped off by some dodgy plumber he transfered me to a technical advisor who told me it would be the overheat thermostat.
Gave me a part no. & told me to contact INTERPART.
Cost: £8:45 + vat.
Cost @ online spares shop: £20
Hope this can help others too.
Kev (Question asker)
March 2006