Electric boiler/immersion only heats half a tank..

[thewarden]

Hello, I live in a house with no central heating.

Our hot water is provided via a copper boiler about 5ft tall and is heated overnight when the electric is on low rate. its on an immersion switch which is alway on.

Anyway, about a month ago we stopeed getting hot wate, so I replaced the thermostat. This didnthelp, so I went to change the immersion, I couldnt get this off because it was completley corroded on.

In the end I ttok the whole thing out and went for a replacement from b&q.

My old boiler had an immersion that ran right across the bottom of the boiler. The cold water entering at the bottom. The man at the DIY store said you can no longer get this type and sold me a different style, this one has an immersion that enters from the top and goes about half way down the tank, however the cold water still enters at the bottom of the tank.

The problem is the water only heats down to where the immersion heater goes and the bottom half of the tank is cold.

Ive messed with the temperature and can only get a full abth if the water is about 75 deg then topped up with cold.

Is there a way around this? have I been sold the wrong system for our needs?

Any help greatly appreciated.

Thanks.

 

[ChrisR]

It's possible to get tanks with horizontal immersions but you have the result of a quest at B&Q. The best you can do without replacing the tank is to use a 30" immersion, as they're the longest you'll get.

You could stir the contents of the tank by using an Essex flange and a secondary circulation pump, but the pump would probably cost more than a new tank.

 

[thewarden]

Thanks for the advice.

I feel sick...

 

[ollski]

Yep fraid so, a 60" cylinder with a 27" immersion element is only going to get up to temperature in the top 50% of the tank due to heat rising. B&Q have have mis sold it to you though if you fully explained your needs so it may be worth writing a letter to them. Horizontal immersions are still widely available, an economy 7 cylinder without them would be a bit of a waste of time.

 

[thewarden]

Thanks, I wish Id called here first.

Ive just seen one of these, would this help?

http://www.plumbworld.co.uk/95-14815?PHPSESSID=e706e2a0f115882ce97ae8bf933fa6dc

 

[ollski]

well it will heat 60 % of the tank rather than the 45% you have now (presuming the tank was supplied with a 27" heater).

 

[thewarden]

Thanks, ive put in an order it should give me an extra 9 inches..

 

[thewarden]

Hello,

my new immersion arrived, but I cannot get the existing one off now, is this because I put it on too tight or because there is water in the tank?

Do I need to drain it?

 

[Nige F]

Leave the water in and the feed valve to tank open.then crack the immersion undone with a long handleed spanner or stillsons....once started- then drain some water and remove fully

 

[thewarden]

thanks