Elson tank overflowing

[Xray]

I have warm air ducted heating - hot water is stored in an Elson tank in the loft ( water is heated by a gas burner in the warm air unit). Approx every 6/12 the hot water tank overflows - I have had 3 new ball valves fitted since last summer ( and about 6 before that , the first only 3/12 after the new tank was fitted ) and this weekend this has happened again. Plumbers say that "it can only be the ball valve" as there is nothing else in the tank to cause this fault, but my neighbours don,t have this problem. When a new ball valve is fitted all is well for a while and then the overflow starts running again usually after about 6/12. The tank is only 7yrs old and replaced a similar system. I have a combi mate fitted under the kitchen sink and the problems began soon after this was fitted.Is this a coincidence or could there be a connection ?
Any ideas much appreciated?

 

[picasso]

the cold mains is finding its way back to the elson, probably through a mixer tap or shower, try isolating the kitchen taps and see if the tank still drips.

 

[Xray]

the cold mains is finding its way back to the elson, probably through a mixer tap or shower, try isolating the kitchen taps and see if the tank still drips.

Thanks - I turn the mains stop tap off and this stops it running. I have no DIY knowledge but should the ball valve in the Elson tank not stop the mains cold water from overfilling the tank? Is this difficult to fix if it is connected to a problem with the shower or taps as you suggest or would a replacement tank be the best solution? Has the tank been fitted incorrectly?
Forgive my ignorance.
I have a Triton shower overbath shower.
Thanks

 

[rojaca]

I believe your elson may be a thermal store, in which case it is most likely a pinholed coil. If so changing the floatvalveisn't going to do anything no matter how many times it's changed.

 

[Xray]

I believe your elson may be a thermal store, in which case it is most likely a pinholed coil. If so changing the floatvalveisn't going to do anything no matter how many times it's changed.

The tank is just used to store the hot water - does a pinholed coil mean that the tank needs replacing ? I know nothing about plumbing I am just tired of this problem which seems to be never ending.
Thanks for your help

 

[Terrywookfit]

What does the badge on the Elson say?

 

[Xray]

What does the badge on the Elson say?

Sorry I can,t find out - I am a lady over 60 years of age, live alone and can,t get into the loft , just trying to see if the only solution is to replace this tank. I have thought for ages that continually replacing the float is not solving the problem and am trying to get some ideas as to what could be happening from this forum.British Gas are attending tomorrow and I am sure they will once again change the ball valve.
Even phoned the Elson techical help line earlier in the year but they also said it must a faulty ball valve causing the problems.
Thanks for the reply.

 

[rojaca]

Hi xray, could you tell us the model of the elson tank. we have to work on them occasionally, but i don't know the entire range.
Hava a look on the tank for a data badge, sometimes you might find that this is behind the plastic cover behind which the immersion htr sits-follow the cables. TURN OF THE POWER BEFORE REMOVING THIS COVER.

 

[rojaca]

sorry OFF

 

[Xray]

sorry OFF

Thanks,

There is no immersion heater - the tank just stores the hot water which has been heated by a gas heater in the warm air unit .Unfortunately I can,t get in the loft to get the details on the tank - I am over 60 and live alone .

 

[picasso]

Is the shower you have electric ?

 

[Xray]

Is the shower you have electric ?

Yes - A Triton T80XR . only 2 yrs old. The problem was there before this was installed , previously I had an old Triton shower.
Regards
Xray

 

[picasso]

If you have an electric shower I very much doubt you have a thermal store, I still think your problem is the cold water back feeding up the hot water system.

 

[Xray]

If you have an electric shower I very much doubt you have a thermal store, I still think your problem is the cold water back feeding up the hot water system.

Thanks
So why does the ball valve in the Elson tank not stop the tank from overfilling?As I say I have no DIY knowledge. Would the back fill cold water go to a different part of the tank than the part with the ball valve ?
Apolgies if this is a stupid question but I know nothing about these tanks except the ball valve works on the same priciple as how it works in a toilet cistern.
Xray

 

[picasso]

The cold water (if this is the problem) will be passing from the cold supply across a tap or washing machine connection back up the hot water pipe and making the tank over flow, when your plumber comes explain that the ball valve has been changed several times and you think the problem lies elsewhere.