DIY Doctor

Header tank

Postby russellfl » Wed Jul 02, 2008 7:37 pm

Hi, having recently moved into a 1970's bungalow I have been finding my way around the central heating system. I have (i believe) an open vented system which has two tanks, one an expansion tank for the boiler and the other a header tank for the immersion cilender. I
have found out that the bathroom and toilet cold water supplies are fed from the header tank and not from the rising main. Is this normal? bearing in mind that we have been using the cold tap for drinking purposes?

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Simply Build It

Postby Skids » Sun Jul 06, 2008 3:10 pm

Hi russellfl

If you have found your way around the central heating system your are doing well, please understand there are many configurations, however you will have ‘two sides’ to your system; a. the ‘cold water supply’ that feeds the cold taps and the Hot Water Cylinder’, and b. the ‘hot water supply’ that feeds the hot taps, heated by a boiler with a back up immersion heated.

If you have a ‘open vented system’ you should have the following configuration:

“one an expansion tank for the boiler” this should be the small one (18ltr) and called the ‘F&E tank (feed & expansion), it keeps the boiler system fed with water and should have: a cold feed from the maims regulated by a float valve, a feed pipe running to the boiler which connects to the boiler primary return pipe (no isolating valves on this feed pipe!!), and have a ‘open vent pipe’ coming from the boiler primary flow pipe which vents above the tank and is used as a safety device which enables the expanding hot water to ‘go somewhere’ rather than blowing up the system, this vent MUST NOT have any isolating valves on it!!

“and the other a header tank for the immersion cilender”, not called the “header tank” or the “immersion cilender” but called ‘Cold Water Storage Cistern’ (CWSC) and the ‘Hot Water Cylinder’ (HWC), this tank will/should be the big one.

The “HWC” can either be heater by an independent boiler somewhere in the bungalow or by an ‘immersion heater’ which screws into the top of the HWC and powered by electric.

Yes this is normal as the only ‘mains drinking water’ will be the ‘kitchen cold tap’ and ALL other taps, hot and cold are fed somehow from the CWSC

Said you were doing well, BOL


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Postby Perry525 » Sun Jul 06, 2008 6:08 pm

Until recently it was the norm for hand basins and baths to be feed off the cold water tank in the loft.
Things change and modern homes have mains feed.
There are millions of older homes where the hand basins are feed from the cold water tank.
Consider the advantages, the cold water main bursts up the road.
All mains feed taps run out of water. You can still wash, make a cup of tea, carry on as normal.
For a few pounds you can fit drinking water taps alongside hand basins and have the best of both worlds.
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Postby ericmark » Mon Jul 07, 2008 4:14 am

It allows showers to be used as pressure for hot and cold are the same and yes it does mean you have no potable in bathroom although if it has good lid with amount of water that runs through it in real terms you are unlikely to have problems.

Postby russellfl » Mon Jul 07, 2008 4:12 pm

Thanks to all of you who responded, I now feel much happier, just wanted to check it out.

Cheers to all!!
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