Sorry if this is a load of daftness - I've not a clue about heating systems! Not long moved and the house has its got an Ideal Independent C30 boiler. Issue I'm having is the CH turns on quite regularly even when the thermostat is much lower than the house temp (set to 15°C and house temp is 21°C for example) and the pre-heat option is off. Got the dial set for winter mode and on manual mode (on) so not on timer. Anyone know why CH keeps coming on? Boiler is in open plan kitchen mounted on outside wall if that helps. Thanks.