Between you all I think you may have cracked it. The magnet sticks to the horizontal pipe inbetween the vent pipe and the pump. I assume this pipe will need to be cut out and replaced and the system flushed! Am I right in saying this or is there an easier way?
Thanks again all
Matt
Sorry Tincup, I don't quite get what you're saying! I can isolate the ball cock by turning off the ball valve (or tying it up), no probs there. Just the rest of it I don't get.....can you explain it as though my 5 year daughter daughter would understand (i'm a bit of a novice I don't mind...
To categorically rule out the ball cock, I would suggest isolating the water supply to the filler valve on the tank (assuming there is an isolator valve somewhere nearby) and then see how it goes for a few days. If the tank no longer overflows, you know where the problem lies.
Going to give...
My overflow regularly drips water from the header tank, in the short term I often empty some of the water with a jug but there's clearly a problem here!.
I've witnessed the vent pipe spilling water into the tank - the water in the tank is usually warm/hot and it is rusty in colour - the ball...