Gravity fed system but told i cant install a shower pump??

23 Dec 2009
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United Kingdom
Recently splashed out on a steam shower system for a christmas treat. It needs a balanced water pressure to work effectively.
I have a cold water tank in loft and hot water tank in airing cupboard and so identified my system as a gravity fed system and so bought a 3 bar twin impellar water pump to be installed. However the guy i got in to price up the job says that the cold is actually mains fed and so will not install pump. Please help, i have a feeling hes wrong as all the diagrams i look at online scream that it is a gravity fed system which m,eans it should be fine to install the pump....
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is this the type of cylinder you have ?

with two tanks in the loft ?
what is he saying is cold mains feed ?
have you any pics ?
Sounds like he doesn't know what he is talking about :rolleyes:

The cold feed for the shower will come direct from the cold storage tank that supplys the HW cylinder, to the pump, and the HW supply from the pump should come from its own fitting on the HW cylinder, thereby giving you a fully balanced supply.

Your only possible problem could be, especially with a 3 Bar pump, that the cold storage tank is not big enough to supply enough water to keep up with the pump.

I have assumed that by 2 tanks, you mean 1 large and 1 small, which would be the heating expansion tank.

However you may have 2 large tanks in tandem. You need to clarify this first.
I have a cold water tank in loft and hot water tank in airing cupboard
What you describe is a gravity hot water supply (By "hot water tank" in the airing cupboard I am assuming you mean "hot water cylinder" as per the photo from seco services) The existing cold water supply will probably be direct from the cold water main at a higer pressure and if so it will not presently be balanced.

However a gravity cold water supply can be taken from the tank in the loft to feed the pump. Then as both hot and cold supplies come from the same tank, they would be balanced, as per the diagram below.

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how big is the tank in the loft? You may have a combined hw cylinder which means all the cold taps will be mains fed.
thats a standard gravity hw cylinder
so no prblem adding a pump to the system as shown above.

fit a surrey flange or essex flange to the cylinder



and cold feed from the cws.
and cobble a bit more wood round the storage cistern :eek: some diagonal braces of 6x1 inch timber wouldn`t go amiss
Thats quite a small tank in the loft and there is only ONE downfeed which is likely doing the hot.

So cold must be off the mains. You would need to change to a larger storage tank in the loft and take an additional cold feed to the shower from it.


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