Indirect mains pressure cylinder

SMG · 18 May 2008

I have recently had my boiler renewed for a new condensing type, I have a 5 year old sealed system in very good condition, fully pumped, s plan, well maintained with a copper D/H/W cylinder & cold fill tank in my loft. I am considering replacing the cyl with a new stainless steel 210 ltr Indirect mains pressure cylinder.

Somehow, it seems there is a lot of very hot water up there & I would dread it bursting & scalding anyone. There isn`t anywhere else it could go.

My question is, is it safe to have the new cyl in the loft?

Softus · 18 May 2008

SMG said:
...210 ltr ...is it safe to have the new cyl in the loft?

>210kg would probably need some load spreading, but if the risk of bursting is too great then could you install it onto a waterproof tray (or tiled platform) with an outlet that takes the water safely away from the occupants, and/or with a moisture detector coupled to an alarm?

JPC · 18 May 2008

is the existing cylinder also in the loft, if so nothing changes, if not cant it go where the existing one is ?

SMG · 18 May 2008

Thanks for your replies. I don't know of a tray that would take that amount of water, but spreading the load would be easy, the existing cyl, (140 ltr) is sat on a sturdy timber frame, which is central over an internal brick wall. My concerns are, of the cyl bursting somehow during the night.

I`m probably a bit paranoid since I read about water scorching the occupants of a house. How safe are these modern mains cylinders compared to the standard indirect copper type?

ChrisR · 18 May 2008

The dangerous ones are plastic, and let go when they end up with boiling water in them due to a failure of one thermostat.

Yours will be probably stainless steel,
have a nuber of thermostats
will never have boiling water in it
must be installed by a registered installer
will be rated to stand about 10 bar
have a pressure reducing valve to restrict it to about 3 bar
will have two pressure relief valves both of which send water out safely well below the safe pressure for the cylinder
and your mains is probably no more than 4 bar.

Does that help?

SMG · 18 May 2008

Yes, absolutely. I didn't know you could get plastic cylinders. So, basically, there is no difference with the new s/s cyl to the copper one except for the increase in pressure, & the safety valves.

Can anyone reccomend a good cyl, must fit through a 2 foot sq hatch.

I want to be able to specify the cyl, not just the ones he gets a good price on.

BigBurner · 18 May 2008

Your concerns are legitimate of water damage, scalding, etc. Ever thought a high flow multi point instant water heater. Rinnai and Andrews do them and models that will fit outside as well. Then no problems of water damage as most of it is outside.

If you go for an unvented cylinder be aware of the yearly service charge. One recent post mentioned a plastic pipe bursting on an unvented cylinder when one of the safety devices failed. Make sure all pipe is in copper.

SMG · 18 May 2008

Thats exactly my concern m8, thanks.

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Indirect mains pressure cylinder

BigBurner

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