Cylindrical tank overflowing in airing cupboard

[Nottoobright]

So my fiancée and I moved into our first house last week and today when running a bath I found my hot water tank overflowed and leaked through the floor to the room below!

I will bullet point everything I did to lead to this and what I think happened, however I have ZERO plumbing knowledge so I will try my best to explain

System:
--Gravity fed, electrical heating, hot water tank in the airing cupboard
--small cold water tank in the loft (above the hot water tank)
--combination boiler in kitchen (ground floor)

Scenario:
--water pressure was very low when we moved in. I loosened the stopcock on the water supply and now the pressure is good
--turned on boiler for the first time to try and run a bath
--after a short while I heard a dripping from the room below the airing cupboard
--the hot water tank was overflowing straight onto the floorboards
--I noticed that the water was not coming in from the cold water supply (which has a ball cock valve) but coming in from a small hole near the lip of the tank. See the pictures in my album

I am very confused, I have tried looking up online what has happened but I have failed! Any information would be very grateful and if any more information that I have missed but would help diagnose the problem, please just ask... Thanks in advanced

 

[Nige F]

electrical heating, hot water tank in the airing cupboard
--small cold water tank in the loft (above the hot water tank)
--combination boiler in kitchen (ground floor)

I am very confused,

So am I - it`s probably not a combi boiler . In your pic. album there is a pipe next to the float of the ballvalve - it`s an overflow , it should go outside ( or maybe into a manifold in the bath overflow) it should be visible @ it`s end and the water that`s spilling over should be going down this pipe and away safely .Check that first then we`ll move on to maybe why it`s overflowing

 

[Tipper]

That type of cylinder is a 'Fortic' or combination cylinder, ie it has a small cold water header tank built in on top of the hot water cylinder.

You need to lower the water level in this top tank to stop it overflowing. It probably needs a new float valve as it may be passing which is why the stop valve was shut?

Lower the water level by either bending the float arm down a little or adjusting the float position on the arm but often the screw fixing the float shears off so be careful!

There should be an overflow pipe from the top tank to the outside, if not then fit one if there is a suitable route to the outside. Any other holes, not the overflow of course, should be closed off to stop water overflowing everywhere.

BTW the small tank in the loft will be the header tank just for the boiler/heating system and nothing to do with the hot water.

 

[Nottoobright]

Thanks for the help

I now h e a much better understanding of my tank and hot water system,

I probably did not word the question very well though, when my tank overflowed the water was not coming from the float valve but from the small hole in the tank near the rim.

I have had another look and it appears that the hole in question is connected to an insulated pipe (insulated in the same yellow/orange foam as the tank) which comes from the lower section of the tank, where the hot water is stored.

I do have an overflow pipe but I do not think it was effective enough to stop the tank from over flowing.

Should this hole be there? And if not why is water coming into the cold water tank?

Again any hel,p advice or knowledge is much appreciated.

Cheers

 

[flameport]

The hole and insulated pipe should be there, and if water is coming out of it, at least one thing is wrong.

A likely cause is a faulty mixer tap or shower incorrectly connected to the cold mains and the hot from the cylinder, which is causing cold water to be fed back to the cylinder via the hot pipe.

The cold flow being turned down low was probably to cover up this problem, as if the flow rate was low enough, it could all be handled by the overflow.

 

[Nottoobright]

Ah! This could be it then! The overflow did happen after running the mixer shower for a long time (trying to clean the bath tub).

Thanks so much for the help

 

[Dextraneous]

I'm intrigued by the Flintstones wallpaper in the cupboard

 

[Nottoobright]

Haha great spot! As I said we have just moved in and the previous owner was "eccentric" to say the least