Hi Please help!!!!!!!! I have a potterton lynx 2 combi boiler, it works fine for hot water, but i have recently added a addtional radiator since then the central heating is constanly running it nevers cuts out as it used to, before it used to run for about 30-40mins and cut for 10-15mins now it runs for 3 hours then i have to turn it off. the control on the front is set to under half way, there is a total of 6 rads and 4 are doubles the biggest is 520x2000mm Any ideas