Replacing cold water tank

[lxbn]

The existing cold water tank is a metal one sited in the airing cupboard directly above the HW cylinder - it's in a flat. The tank size is about 50 x 60 x 90 cm (wxdxh) - it's the ideal size for the airing cupboard.

I would like to replace it but it's quite difficult to find a new tank of dimensions that would fit in the space. The flat is all electric with no gas supply so hot water is heated by immersion heater. I have read in these forums instances where the thermostat on the immersion fails and the water in the cold tank gets very hot from water in the HW cylinder expanding into the cold tank. As the new tanks are plastic would they fail if something like that happens? Are there no safety cut offs in immersion heater thermostats?

If I could completely do away with the cold tank, that would be great but I'm not sure if that is possible without the option of using a gas combi boiler. The cold tank supplies the HW cylinder and the cold taps and WC cistern in the bathroom next door. There is also an electric shower installed which works great as it is.

 

[Deleted member 105431]

how about an unvented dhw cylinder if you have a good water main. (no tank reqd)

 

[lxbn]

how about an unvented dhw cylinder if you have a good water main. (no tank reqd)

good idea but these are complicated pieces of kit and quite costly to buy and install. And although they do have immersion heaters, don't they usually work using the central heating system for heating the water? The ones I know do - my sister recently had a megaflow installed at her house and it works very well even better than I expected. Well, a lot of the pipes had to be changed starting with the mains!

 

[Deleted member 105431]

how about an unvented dhw cylinder if you have a good water main. (no tank reqd)

good idea but these are complicated pieces of kit and quite costly to buy and install. And although they do have immersion heaters, don't they usually work using the central heating system for heating the water? The ones I know do - my sister recently had a megaflow installed at her house and it works very well even better than I expected. Well, a lot of the pipes had to be changed starting with the mains!

you can get direct unvented cylinders that run off immersion htr only and they are worth the money.

 

[JohnD]

Are there no safety cut offs in immersion heater thermostats?

Yes, modern immersion heaters have an Overheat Cutout which is in addition to the usual thermostat.

If you can post a pic of the top of your immersion heater (after isolating the circuit) under the plastic cap, someone may recognise what sort you have.

//www.diynot.com/forums/viewtopic.php?t=129539

 

[lxbn]

If you can post a pic of the top of your immersion heater (after isolating the circuit) under the plastic cap, someone may recognise what sort you have.

//www.diynot.com/forums/viewtopic.php?t=129539[/QUOTE]

Sorry don't have a pic immediately, but I'll try to explain it. From recollection, the thermostat is a coppery rod with a plastic top that is inserted into the body of the immersion heater.

Is there some way I can recognise an immersion heater that has the cut out feature?

 

[Bahco]

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