Hopefully someone can help me, I've just started using the central heating again, after the summer. The problem is this, when the central heating is running and I turn on the hot water they both seem to work ok. the problem seems to be when i turn the hot water tap off. After about 30 seconds the green light goes off and the flames go out. then after about a minute, the flames fire back up and the heating is ok. This doesn't happen if the hot water is only on for less than 7 seconds.