Boiler keeps going to red light/turning off. I have tried resetting a couple times as per manual instructions but no luck so contacted engineer to come in morning. My question is, should I leave it to Off until he comes rather than have the red light on? Internet seems to suggest this might cause a problem to the boiler but I don't know if leaving red light on is maybe not safe/not a good idea? It's a combi boiler I believe.