Why do I have two header tanks?

Why do I have two header tanks? Well, I know the obvious answer. One heads the central heating and one is the cold water store for the hot water cylinder. But... must I have two seperate tanks? Can I use the same single tank as cold water storage and CH header?

My existing CH header tank sits very visibly on my attic bedroom wall, whereas the cold water storage tank is within the loft space. The cold water tank is about three feet higher than the highest radiator, about 12 feet above the hot water cylinder and about

25 feet above the boiler. Can I get rid of the CH header tank and supply the header feed to the CH from the cold water storage tank?

Ta.

JGH - mdfs.net

Reply to
jgh
Loading thread data ...

The CH circuit isn't (well, shouldn't be!) plain water - it has inhibitor and stuff in it, so it's not compatible with the cold water circuit.

cheers, cive

Reply to
Clive George

I thought so, and now you mention it I remember pouring a bottle of stuff in the tank last time I drained the system to fit a new radiator.

I shall have to see if I can snaffle a bit of extra space in the loft instead.

-- JGH

Reply to
jgh

No. The CH water will (should!) contain additives to reduce corrosion and may well be distinctly brown and grubby. You wouldn't want that mixing with the cold water to your taps. Even if you didn't mind it, you'd still lose all your corrosion inhibitor very quickly as the CH water expanded and contracted and pumped it out of the system.

Reply to
Skipweasel

On Sun, 14 Oct 2007 20:14:20 -0700 someone who may be snipped-for-privacy@arcade.demon.co.uk wrote this:-

You could do. However the result would be that the components of your heating system would corrode rapidly, particularly the radiators. This would be due to the fresh water constantly being introduced into the heating system.

If you tried to introduce chemicals to minimise this corrosion you would constantly need to keep them topped up.

Introducing a second header tank was not done on a whim. It was done because of the very real problems with only one storage tank.

Reply to
David Hansen

Reply to
John

If you look above the tanks you'll see an open pipe. This is an expansion pipe and under certain conditions water will come out of it. If you really want to wash in (or even drink) the contents of your central heating system...

Reply to
Dave Plowman (News)

It could be converted to a sealed system, but you'd need space for a pressure vessel to take up the expansion. This could be almost anywhere on the system.

Reply to
<me9

Very much so. Helped a neighbour do exactly that.

Basic components were a pressurized HW tank and an expansion vessel for CH circuit.

He lots the HW tank with it header and the CG header from the bedroom, the electric shower from the bathroom, and fitted the PHW tank in an old coal bunker next to the boiler.

Reply to
The Natural Philosopher

On Mon, 15 Oct 2007 09:02:53 GMT someone who may be "John" wrote this:-

It is possible to convert just about any wet heating system to an "unvented" system. Whether it is viable is another matter. I wonder what the simple payback period of such a conversion is:-)

An easy answer might be to move the F&E tank into the loft. That would only involve extending the overflow, feed & expansion and vent pipes. It would also, presumably, involve shortening the supply pipe from the loft to the F&E tank.

Another option would be to replace the hot water cylinder with a thermal store with built in F&E tank. As long as this is above the highest radiator there is no problem.

Reply to
David Hansen

There is no payback in financial terms, apart from mot having to waste elecricity on pumping showers.

More expensive and less useful than a PHW system.

Reply to
The Natural Philosopher

On Tue, 16 Oct 2007 06:00:00 +0100 someone who may be The Natural Philosopher wrote this:-

That depends.

Why?

Reply to
David Hansen

You seem to be confusing a sealed CH system with an unvented HW system. You can convert many boilers to sealed operation, and yet still retain a vented HW cylinder.

So you were right with the first bit - there is no payback (economically) for conversion to sealed - and you will still need your pump if you have one.

A thermal store would give you the most[1] of the advantage of a PHW system if you want.

[1] i.e. all bar the accumulator functionality.
Reply to
John Rumm

You neglect the slight problem of the effect of bathing in these chemicals.

MBQ

Reply to
manatbandq

On Tue, 16 Oct 2007 09:55:55 -0000 someone who may be " snipped-for-privacy@hotmail.com" wrote this:-

Indeed. I should have mentioned it for completeness.

Reply to
David Hansen

Converting to a sealed system doesn't necessarily give mains pressure hot water.

It does, however, make the system less prone to corrosion, saving long term costs in longer radiator life, less need for inhibitors and power flushing, and less likelyhood of major flood damage from leaks, as they are limited in volume, and pressure losses would make them obvious.

I wouldn't go back to a heating system with a header tank.

Reply to
<me9

- or brushing your teeth in them. (I'm assuming that most people with a cold-water tank don't have a rising-main tap in the bathroom or go downstairs to the kitchen sink to brush their teeth).

Reply to
LSR

That's odd. I was taugh (getting on 30 years ago) that kitchen sink and bathroom basin on rising main 'cos the water gets ingested, bath and show on header tank to balance pressure. Every house I've lived in has been like that.

-- JGH

Reply to
jgh

It seems to vary region by region.

Reply to
Dave Plowman (News)

On Fri, 19 Oct 2007 09:33:29 +0100 someone who may be "Dave Plowman (News)" wrote this:-

The water byelaws could be different in different towns at one time. Some were more in favour of connecting as much as possible to the mains than others.

Reply to
David Hansen

HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.