Header Tank Overflowing - Not the Ball Valve

[sbarrick]

Hi All

This is my first post on the forum, and know little about plumbing. But here is my problem.

My header tanks keeps overflowing. I have replaced the ball valve and checked this several times for leaks to which there is none. So I can confirm that it is not the Ball valve. The tank in the loft continues to fill up over a number of days and overflows via the overflow pipe outside. We have not had our central heating on or the emersion heater and still it is filling up. HOW????

I tested this today, no heating or emersion heater and did not use the hot water for several hours and the tank water depth rose by about an inch.

Our system is an indirect vented system with tank in loft. The Tank is a Showmax Supercal Cylinder.

Can someone please help with advice.

 

[PlumbBobBob]

sounds like the coil in the hot water cylinder is damaged letting water from central heating side into hot water side and backing up into the cwst. or do you have mixer taps anywhere with tank fed hot and mains cold, could be the cold overwhelming the hot and forcing it's way up to the hot cylinder and on up to the cwst.

steve

 

[sbarrick]

We do have mixer taps but we have had them in a while now.

So does that mean new cylinder. What costs are we looking at here to replace?

 

[andf380]

I'd go with the mixer tap passing

 

[Steve001]

I'd go for either of em, but tap 1st then coil and thirdly being as you've said it's not the ball valve I'll go for that too, lol.

Please let us know what happens, no fun in threads with no conclusion

 

[dennyboy]

try new inserts in the taps first, if that doesnt work new cylinder I'm afraid