Putting Two Unvented Cylinders together

[Harden Long]

Hello

As on previous threads, I am putting in an unvented system

We have identified a good "crawl" space behind the en-suite where the cylinder can go-my plumber reckons it is not big enough other than to put a 210 litre cylinder in but says he could fit two of these cylinders together so that we have a decent capacity (I had been hoping to get around 330 litres so by having two of these I actually get more than that)


Is this feasible?

Are there any downsides?


Thanks very much

David

 

[gas4you]

How about 2 x 160 litre cylinders then?

Downside =cost

 

[Harden Long]

Thanks Dave

I suppose I was just thinking that I might as well do the job right from the start-as the kids get bigger there will be more demand for baths/showers etc and I thought that bigger capacity would be a useful thing to do

I reckoned that the cost would "only" be an extra 700 quid or so to put in a second 210 cylinder and the overall 420 litre capacity would be ideal ?

Do you think it would cost much more than that?

Is the performance in any way affected by putting 2 cylinders in?


cheers (as always)

david

 

[Agile]

There is no problem but you have to have the controls connected sensibly!

Its absolutely essential to have the supply and outlet pipework symetrical to ensure the output is coming equally from both cylinders.

I would add gate valves so that they flow rates can be balanced!

Tony

 

[Harden Long]

Thanks Tony-invaluable advice
I will make sure I discuss with my guy
You guys rock!

 

[OllieN]

Just a thought...

I guess that heating 420 litres of water rather than 320 will cost you anually in bills (maybe an issue), and will take longer to heat up (probably of no consequence).

 

[gas4you]

You may find it is uneconomical to run with 2 cylinders as today most cylinders are fast recovery so reheat it very quickly, about 20-25 mins for a 210 litre size, therefore you do not want to be heating a massive hot water store as in 2 cylinders so that they will keep cooling and need re-heating before any water is drawn off and used

 

[Harden Long]

Hhhhm. yes I hadn't thought about those last 2 points.
I may go back and see if I can site a larger single cylinder elsewhere-perhaps in the loft.

I know this is a daft question but is there logistically any problem in where I site the cylinder?
I was originally going to put it in a utility room, next to the boiler but when we saw this crawl space next to the bathroom, it seemed an ideal out of the way place but yet still affording access for maintenance


I do have a pretty reasoanble size loft-would it make sense to put it there?
Is it better to have it near the boiler?

 

[gas4you]

Doesn't matter where it goes as long as you can have a continuous fall from it for the prv discharge pipe. Also bear in mind the weight when full. Each gallon (4.5 litres) of water weighs around 10lbs