Hi, I have a dripping overflow from the CH expansion tank. the ball valve is fine and operates. i have checked the thermosat on the hot water tank and that operates and switches the heating on and off for water when at temperature.
I have noticed that when the heating is on and running there is a flow back from the bottom of the F & E tank as i can see the water flow. when i touch the water pipe at the bottom of the tank it is hot water coming back up.
the water tank is fairly new 4/5 years old, could it be that, how woudl water get back up the pipe.
the pipe that bends over the top is bone dry, so it is def coming in from the bottom.
our water pump was set to 3, so i have changed that to 2 with no difference, rads are all hot with no air?
please help