Hi, hope you guys can help. I have a glow worm swift flow which has caused problems in past but has been working like a dream until few days ago. suddenly no hot water or central heating, with cold weather and 9 month old son not good!. Pilot light on and electricity supply to timer control panel working, just doesn\\\'t fire up.. We noticed that resistor R3 on honeywell dc fan controller burnt out.Are sending for replacement but any idea why it should burn out and is there any thing else we should do? Also some of the upstairs radiators cold on top and hot at bottom, problem related?.