After about 3 seconds of switching on the main fuse (1 Amp) blows.(The fans comes on straight away) I've replaced the relay switch and the spark generator, however the fuse still blows. Any idea what could be causing it ? All elecrical connections seem OK. It was working fine before going on holiday, and was switched off for 1 week.

John Harris, August 2008

I've just had this problem develop. Likewise I replaced the realy switch; problem remains. Any answers? 1 amp fuse is correct.

FL, October 2008

is 1 amp correct rating? 3 amp is usually rec for boiler fused spur

plumbersw15@talktalk.net, August 2008