Cold water tank over flowing

[andyGP14]

My cold water tank is overflowing it isn't the ball valve and the water seams to be entering via the feed for the hot water cylinder. Its not the expansion tank for the central heating system.
The expansion for the central heating isn't overflowing and level is static.

 

[John M]

How old is the installation ?

 

[andyGP14]

About 9 years

 

[Space cat]

There are two common causes of this problem.

1) Water is leaking from a heating coil in your cylinder. If the heating header tank is higher than the cold tank AND is constantly filling up that just about clinches it. Hopefully you don't have this problem!

2) A mixer tap somewhere is allowing mains pressure water into your tank fed pipework. That mixer could be in a shower or at a sink or, just possibly, a washing machine. Mixer taps and showers should always get their cold supply from the tank that supplies the hot water. The only exception to this is a kitchen mixer tap. These naturally need mains cold water - because you have to drink it - but if you look carefully at a proper kitchen mixer you'll see that the spout has two separate outlets. They're not really mixers at all. All the hot and cold fill washing machines I've ever seen also have two separate outlets into the soap dispenser.

 

[Bahco]

Tie up the ball valve on the f/e tank and see if the level goes down.

If it does, your cylinder coil has a hole.

Also , have you recently fitted a mixer tap or shower.

 

[Bahco]

Touche

 

[JohnD]

Assuming you have both a cold-water tank and a Feed & Expansion tank for the boiler; then a leak in the cylinder coil will cause water to flow from the higher to the lower.

it is more usual to have the F&E lower, to prevent contamination of the cold tank if this happens

Which is higher - the top of the water in your F&E, or the top of the water in your cold tank?



If you don't have an F&E, does your boiler have a filling loop, and has it (wrongly) been left connected?

do you have service valves on your various mixers (esp. showers) enabling you to isolate the water supply to them?

My money's on a shower mixer.

 

[andyGP14]

my feeder tank is lower and the ball valve is not letting in any water in.
Sounds like it could be a mixer tap it only a tiny amount over flows and only does it overnight.
Thanks
Andy

 

[Space cat]

Turn off your main stopcock then try the cold on all your mixers. Apart from the kitchen mixer (if any) with its two hole spout, they should all still work.

 

[andyGP14]

I have two mixers upstairs and both only work on the hot water. the house is a Barrat house and is about 10 years old and the plumbing seams to be well done.

 

[JohnD]

if you have service valves on the taps, turn them off. this will probably cure the overflow. If you have two such taps, turn one off one night, and the other off another night. Safest thing is to get new taps (not mixers) but if you can put up photos of your existing ones, the clever plumbers here may have a better idea