Hi I am at my wits end, i have insurance cover for my central heating system and boiler but they can't seem to resolve the problem mainly because it is intermittent but the problem is there more than it is not. Basically the temperature in my house can get up to 28.5 even though the thermostat is set to 21, the repair guy put a new thermostat in and it is exactly the same, he told me it is my pressurized boiler and that the thermostat on this is broken and I need to pay an expert because my insurance does not cover this. I got the expert, he said there was nothing wrong with the pressurized tank or the thermostat or valves associated with it, he checked the centol heating control panel and said he thought it was that so i paid him £130. and he changed it, it did seem to do the trick for around 4 days but now it is back as it was, the only way I can control this is by turning the heating on and off by the boiler on and off - what do I do now - any advice would be very much appreciated 
