Two unvented cylinders in series

[mgheating]

this is theoretically possible but does it contravene any building regs?

i've got a customer who wants a 300litre unvented cylinder in his loft but the height is restricted up there.

 

[Biggles..]

its possible and not uncommon one of the things you have to ensure is that d2 is the correct size to take both discharges at full bore.

 

[bengasman]

Two cylinders paralell is fine, or 5 if you would feel so inclined, I reckon that is what you meant rather than in series. Litterally in series is not really possible.
Bear in mind that 2 cylinders of 310 litre capacity will have a total combined weight or almost a ton. You will need to make very sure that the floor will hold that.

 

[Gasguru]

You join them in PARALLEL

Have you considered a horizontal cylinder instead? They are available with a bit of searching.

 

[Biggles..]

Telford cylinders make them.

 

[mgheating]

You join them in PARALLEL

Have you considered a horizontal cylinder instead? They are available with a bit of searching.

yeah but i'll still have the problem of actually getting it into the loft since the height is restricted and the hatch isn't massive either.


Hmm, just wondering about the logistics of joining them in parallel.

Oh and it's two cylinders with a combined total of 300 litres btw.

 

[Biggles..]

Parallel as in one cold feed tee'd to suply both and each hot water supply tee' to one common hot water supply.

Series would to me suggest cold feed into first cyl, hot water supply into cold inlet of second cyl and second hot water cyl outlet to taps.

 

[mgheating]

Parallel as in one cold feed tee'd to suply both and each hot water supply tee' to one common hot water supply.

Series would to me suggest cold feed into first cyl, hot water supply into cold inlet of second cyl and second hot water cyl outlet to taps.

yeah i was thinking more along the lines of the latter.

So would you just have a cylinder stat on one of them? Because of the parallel supply and demand theoretically they would retain the same temperature. At least with it in series you can be sure that the cylinder wouldn't overheat.

 

[Balenza]

this is theoretically possible but does it contravene any building regs?

i've got a customer who wants a 300litre unvented cylinder in his loft but the height is restricted up there.

Id try and talk him out of putting cylinders up there especially when its restrictive spacewise . ££££ would be the first line of attack.
The discharge pipe from that location will be a nightmare. The Pandorro springs to mind.
Surely he has space on a lower floor level ?.

 

[mgheating]

well he's got a 300L cylinder in his bathroom at the moment where it seems to be completely happy.

as far as i can tell he only wants to move it so that he has more room to keep his towels in there. They must be extra fluffy or something.

 

[AlanE]

So would you just have a cylinder stat on one of them? Because of the parallel supply and demand theoretically they would retain the same temperature. At least with it in series you can be sure that the cylinder wouldn't overheat.

No assuming they are heated by a boiler then each would require a thermostat and motorised valve to control each independantly.

 

[Agile]

There is nothing to stop you from using two cylinders in parallel !

But at a cost of about £1000 plus its an expensive way to have more space for the fluffy towels!

Tony

 

[doitall]

Yes you can connect two cylinders but;

You must have a reverse return secondary circuit or one cylinder could be stagnant

 

[holty]

what about a smaller cylinder with a higher recovery coil, think albion do an unvented. depends on what the dhw requirements are though.

 

[simond]

I suggest you look at the tank in tank range by ACV.

Their reheat time is very quick indeed and you can provide more water for a given cylinder size if space is an issue.