Is it ok to have just one header tank for both hot and cold water?

Is it a good idea to have the hot water take off lower than the cold,
so that if the tank runs low (if someone has all the taps running)
the immersion heater will not run dry?

Presently there is a huge victorian tank for cold water
which feeds a smaller header tank for the hot water feed.

The original huge tank was a bit higher than the hot water header tank,
how much difference will a height difference make?
I guess it will mean that the taps run a bit slower.

The plastic tank I am installing is 181 litres / 40 gallons

[george]

"george (dicegeorge)" wrote in message
...
Is it ok to have just one header tank for both hot and cold water?

It is normal practice to use one tank only for cold supply and
the supply to the cylinder.

Is it a good idea to have the hot water take off lower than the cold,
so that if the tank runs low (if someone has all the taps running)
the immersion heater will not run dry?

It is not possible to run the cylinder dry by running taps.

Presently there is a huge victorian tank for cold water
which feeds a smaller header tank for the hot water feed.

Are you sure that the smaller tank is suppling the cylinder and it is
not the feed & expansion tank for the boiler?

The original huge tank was a bit higher than the hot water header tank,
how much difference will a height difference make?
I guess it will mean that the taps run a bit slower.

The plastic tank I am installing is 181 litres / 40 gallons

[george]

In article ,
george (dicegeorge) wrote:
Is it ok to have just one header tank for both hot and cold water?

It's the usual way.

Is it a good idea to have the hot water take off lower than the cold,
so that if the tank runs low (if someone has all the taps running)
the immersion heater will not run dry?

The storage tank can't run dry - the water take off is from the top, not
bottom.

Presently there is a huge victorian tank for cold water
which feeds a smaller header tank for the hot water feed.

Strange. Perhaps it made the pipework easier when adding the hot circuit.

The original huge tank was a bit higher than the hot water header tank,
how much difference will a height difference make?
I guess it will mean that the taps run a bit slower.

It's usually the hot which is slower due to longer pipework and therefore
resistance. But the more height you can get the better.

The plastic tank I am installing is 181 litres / 40 gallons

--
*The closest I ever got to a 4.0 in school was my blood alcohol content*

Dave Plowman London SW
To e-mail, change noise into sound.

On 16 May, 11:53, "george (dicegeorge)" wrote:


Is it a good idea to have the hot water take off lower than the cold,
so that if the tank runs low (if someone has all the taps running)
the immersion heater will not run dry?


On the contrary it is good practice to have the cold slightly lower
than the hot water cylinder's cold feed. The reason is that someone
using a mixing tap/shower won't get scalded by the cold running out
while the hot is still going.
A thermostatic mixing valve should stop the cold in that event
anyway, and we've all tested out TMVs recently, heven't we?

On 16 May, 13:04, Onetap wrote:

*A thermostatic mixing valve should stop the cold in that event
anyway, and *we've all tested out TMVs recently, heven't we?

Darn! Brain malfunction.

A thermostatic mixing valve should stop the HOT in that
event...........

george (dicegeorge) wrote:

Is it ok to have just one header tank for both hot and cold water?

ok, and quite normal...

Is it a good idea to have the hot water take off lower than the cold,
so that if the tank runs low (if someone has all the taps running)
the immersion heater will not run dry?

No, you want it the other way round - so if you drain the header tank
completely, the hot stops before the cold. Saves a risk of scalding.

(no need to worry about the tank running dry - it can't since it is
emptied from the top and filled from the bottom - once you have no
pressure from the header the water just sits in it)

Presently there is a huge victorian tank for cold water
which feeds a smaller header tank for the hot water feed.

It probably made sense to someone when they installed it!

The original huge tank was a bit higher than the hot water header tank,
how much difference will a height difference make?

1 bar of pressure is 30' of head. So in absolute terms very little,
although in relative terms you may find a shower head that is say only
4' below the header tank water level, gaining an extra couple of feet
makes for a 50% improvement.

I guess it will mean that the taps run a bit slower.

The plastic tank I am installing is 181 litres / 40 gallons

Don't forget the tight fitting lid...


--
Cheers,

John.

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John Rumm wrote:
xxxx

The plastic tank I am installing is 181 litres / 40 gallons

Don't forget the tight fitting lid...

Why tight?

Isnt it just to stop spiders getting into the water?

[g]

george (dicegeorge) wrote:


John Rumm wrote:
xxxx

The plastic tank I am installing is 181 litres / 40 gallons

Don't forget the tight fitting lid...

Why tight?

Isnt it just to stop spiders getting into the water?

Well you want a water bylaw mumble kit - as you say keeps crud out
etc. So tight as in not a board just sat on top...

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

John Rumm wrote:
george (dicegeorge) wrote:


John Rumm wrote:
xxxx

The plastic tank I am installing is 181 litres / 40 gallons

Don't forget the tight fitting lid...

Why tight?

Isnt it just to stop spiders getting into the water?

Well you want a water bylaw mumble kit - as you say keeps crud out
etc. So tight as in not a board just sat on top...

We get more crud in the cold water storage tank from the water itself.
The bottom of the tank gets a coating of black crud. When our US
visitors leave tomorrow, I can find time to get rid of it.

I have posted in the past about this and wondered if I could put
something in the tank to break it up and flush it out through the cold
water taps. I was advised to use a brush to break it up and flush out.

Dave