Hope someone can help I've had the gas engineer out from Scottish Power out to this fault he said it was due to the boiler being sludged up after taking a discoloured water sample after pointing out that my system had been chemically cleaned 12 months earlier he claimed that it hadn't worked so I contacted the engineer that did the clean he tested the sample with a filter magnet all Ok second Scottish Power engineer came out agreed that the boiler wasn't sludged up and that the thermal fuse was faulty this we found out can not be purchased separately from the heat exchanger at a cost of around £500 and Scottish Power will not cover it through the insurance my engineer has proved it is the fuse by bypassing it temporarily and the boiler works fine no noises is there anything like aftermarket fuses or any help in dealing with claiming off Scottish power[/quote]