joing two copper cylinders

[Ted 1947]

We moved into our house 5 years ago and inherited a warn air system combined with a large direct copper cylinder.
We have recently installed a new wet heating system which provides heating via a condensing boiler. We would like to use the new system to provide our domestic hot water. Therefore, would it be possible to connect a smaller indirect cylinder to the existing direct system. The existing domestic cylinder is installed in a cupboard in our bathroom ( 1st floor) and the new indirect cylinder will be sited within the boiler room ( ground floor)?

 

[Myfordman]

If the smaller cylinder will hold enough water for you then just use that and disconnect the old direct one.
Storing any more hot water than you need is wasteful as no matter how much insulation you have, the heat will escape - just more slowly.

 

[Mike.S]

I don't know is my answer to your specific question. However, like Myfordman I'd be inclined to just have one cylinder - fed by the new boiler.

With the direct cylinder I assume this is vented (CW tank in loft/upper floor) and uses an electric element to heat the water. Electricity is usually more expensive to use than gas and is often limited to night-time (or whenever the timer can use 'Economy' electricity). This means you can run out of hw during the day as the drawn-off HW is used and replaced with CW which isn't heated until the timer kicks in.

With the boiler, this will heat the cylinder whenever either the central heating or HW cycles are on, giving more HW and at a more economical rate.

One other thing to bear in mind is that if you instal the cylinder in the ground floor then you will lose some pressure as the HW is fed back up to the first floor (assuming this is where the bath/showers are located). Usual options to consider are to either to just replace the cylinder on the first floor with a properly sized indirect one (and sell the old one) or, if pressure isn't an issue (e.g. 'cause you have loads) then keeping all the plumbing bits together on the ground floor makes sense and will allow you to free up the space in the bathroom i.e. strip out the old cylinder and associated pipework.

HTH.

 

[Myfordman]

If you have an immersion in the direct cylidner and are willing to remove it, you could fit a hot rod instead and plumb that back to the boiler with a diverter or a pair zone valves to control DHW and CH flow.
http://www.vaheating.co.uk/hotrods.html

 

[Ted 1947]

thanks for your comments guys, they are very helpful - I think that the way forward will be replacing the direct cylinder, located on the first floor, with an indirect type with back-up immersion. This will be relocated local to the new boiler position on the ground floor.
I didn't know about the hotrod conversion!

Thanks again

Ted