Immersion Heater Cylinder (combi) head

[eyehefbee]

I'm replacing an existing direct copper cylinder. There's no boiler, just an immersion. The old cylinder has a header tank in the loft and there's a pipe which goes from the old cylinder to the loft which is badly sited right under the roof space (touching slate!) and freezes in winter. It's a holiday cottage and often unoccupied so I'm going for a combi cylinder with a built in header tank.

So, in addition, the bathroom has a sloped ceiling from about 7.5ft down to just over 5ft. I want to put the tap-end of the bath at the 7.5ft end so that I get maximum head height for an electric shower. This means that the cylinder needs to go at the 5ft end. The alternative is to put the cylinder at the 7.5ft end and shift the bath down. But this means that, at 6ft 2in, I may be banging my head when in the shower...

So my question is, if I put the cylinder so that the water level of the integrated header tank is at around 5ft, drawing off hot water via 22mm pipe to the bath taps which are at about 2ft, is there enough head to fill the bath within a reasonable time?

Thanks in advance for any assistance or opinion you can give.

 

[dontknowitall]

The built in head tank is puzzling me. Normally if you have a combi boiler you do away with cisterns and hot water cylinders as the boiler heats water on demand.

I've now read your post at least three times and I think you have a confusion here!!

If you have a combi you won't need a cylinder for the shower. If you have an electric shower all you need is a mains cold water supply.

If your mains pressure and flow is good enough for a combi boiler then your "problems" listed above will be no more.

 

[eyehefbee]

Thanks for your reply.

The combi is confusing. It refers to the fact that the cylinder is a 'combination' i.e. combined cylinder and header tank in one unit. Nothing to do with the usual use of 'combi' as in combi boiler! I don't have a boiler just an immersion, it's in Wales, no gas...

 

[oldplumber]

Why not get a direct unvented cylinder and do away with the combination cyl idea, water will then be at mains pressure and should fill your bath ok and you wouldnt need an electric shower but a normal mixer unit. dont forget to employ a unvented qualified plumber to fit it to ensure all the safety features are installed correctly

 

[dontknowitall]

Ah!! One of those!!! I think they're called primatic cylinders but I'm not sure.

The shower would be easiest as a standard electric shower running off the cold mains.

Re the bath, I think it would work but I'm not 100% sure. In theory you have 0.1 bar pressure (1 bar = 10m of head).

 

[oldplumber]

primatics were around with Noah and his arc, time to go modern with the unvented sytem one thinks

 

[Dannypipe]

He doesn't mean a primatic cylinder he means a combination cylinder as made by Fortic. I've never actually come across a primatic cylinder in the field but basically the deal with them is an air bubble seperates the primary and secondary water rather than a physical barrier.

Do as suggested and have a unvented cylinder fitted. Better pressures, but you should have it checked every 12 months by a qualified plumber.

 

[eyehefbee]

Great advice. I'd never thought of using an unvented cylinder. When I looked them up, they are a lot more expensive. But now I don't have to buy an electric shower, cabling, new consumer unit and Manweb upgrade. So it's going to work out a lot cheaper in the end.

Thanks again for advice.

 

[dontknowitall]

Thank you Dannypipe - I knew I was not quite right!!