Hi, hope someone can help. My 85 year old neighbour's heating comes on everytime she puts on her hot water. i know a bit about plumbing and thought it might be reversed circualtion, but she has a 3 port mid position valve, not 2 port, or 2 x 2 port valves. this problem only started a couple of weeks ago. could it be that the switch in the valve is stuck and the valve needs replacing? the motor runs when the heating comes on. I've asked around and have been told with the 3 port the valve it would be the other way around, the hot water comes on with the heating. can someone point me in the right direction so i can help get this fixed. thanks!