I would like some general advice from people/professionals that understand a lot more than me. British Gas recommended and installed a replacement central heating boiler for me, installation went fine. The boiler works fine when heating is on continuously. However bills wise that's not an option. Whenever heating is off, system shuts down and won't come back on. Have had 2 call outs to look at system and engineers both said the boiler is too sensitive for my old house, problem was the water returning to the boiler is too cold and this results in the system going off. Has happened whenever I try to shut my heating off(when no one's at home) If this simple explanation is right??? Did British gas sell me an unsuitable boiler? One engineer said wouldn't happen with a Worcester boiler as it's not so sensitive. Totally confused and worried about bills if heating on continuously.