I live in a block of flats where cold water is gravity fed from a
large, shared water tank on the roof (about 20 ft above). I want to
install a pump to provide a high-pressure shower, but all installation
guides I've read insist on an independent cold feed from the tank to
the pump, which I can't provide.

Can I still install such a pump if I tee off the hot and cold supplies,
and put check valves on the non-pumped branches to prevent the pump
from sucking water or air back from the taps?

Vaci

I live in a block of flats where cold water is gravity fed from a
large, shared water tank on the roof (about 20 ft above). I want to
install a pump to provide a high-pressure shower, but all installation
guides I've read insist on an independent cold feed from the tank to
the pump, which I can't provide.

It will work without a separate feed. The main concern is actually that
you'll "steal" the water from others sharing your tank if they don't have
independent feeds from you, which may be antisocial (or even against your
lease terms). If everyone has their own pipe back to the tank, it won't
matter, unless the tank is undersized.

You should have the check valves anyway if it is a shared supply.

Christian.

The feed is shared with at least some of the other flats, but I doubt
if that will cause any problems as the tank and supply are both
substantial - the downpipe is at least 60mm where my private 22mm
branch comes off!

The feed is shared with at least some of the other flats, but I doubt
if that will cause any problems as the tank and supply are both
substantial - the downpipe is at least 60mm where my private 22mm
branch comes off!

It'll probably work then. Turn the pump right down so you don't reduce the
pressure in the shared downpipe.

You may still get issues, though. Firstly, your lease may explicitly forbid
it. Secondly, the transmitted noise through the pipes may be considered a
nuisance.

You should certainly get a top quality pump designed to reduce vibration and
use it on a low setting.

Another alternative which will always work, if you're lucky enough to have
the space, is to simply have your own tank fed from the communal one and
pump from there.

Christian.

On 25 Feb 2005 06:04:22 -0800, "Vaci" wrote:

I live in a block of flats where cold water is gravity fed from a
large, shared water tank on the roof (about 20 ft above). I want to
install a pump to provide a high-pressure shower, but all installation
guides I've read insist on an independent cold feed from the tank to
the pump, which I can't provide.

Can I still install such a pump if I tee off the hot and cold supplies,
and put check valves on the non-pumped branches to prevent the pump
from sucking water or air back from the taps?

Vaci
Have you got room to fit a header tank in your flat then run your hot
water from that? Then you can also run the cold for the pump off it. I
suspect that would be your only way of getting the shower you want.
The flow from the tank on the roof is probably quite low, have you
checked the litres per minute you get now?

Basil

Well, there is space for a small header tank, but I don't really want
to add another component to my system.

The flow from the roof tank is actually quite good as the pipework is
oversized. I guess if a pump isn't feasible then I will just use 22mm
pipework all the way to the shower mixer. I don't want to fork out for
a high pressure pump and mixer block before I find out I can't use it!

"Vaci" wrote in message
oups.com...
Well, there is space for a small header tank, but I don't really want
to add another component to my system.

The flow from the roof tank is actually quite good as the pipework is
oversized. I guess if a pump isn't feasible then I will just use 22mm
pipework all the way to the shower mixer. I don't want to fork out for
a high pressure pump and mixer block before I find out I can't use it!


Put a pump on with a non return valve on your cold supply from the communal
header tank.

What do you have now? Do you have a conventional open vented cylinder? Is
the open vent running to up and over the header tank?


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"basil" wrote in message
...
On 25 Feb 2005 06:04:22 -0800, "Vaci" wrote:

I live in a block of flats where cold water is gravity fed from a
large, shared water tank on the roof (about 20 ft above). I want to
install a pump to provide a high-pressure shower, but all installation
guides I've read insist on an independent cold feed from the tank to
the pump, which I can't provide.

Can I still install such a pump if I tee off the hot and cold supplies,
and put check valves on the non-pumped branches to prevent the pump
from sucking water or air back from the taps?

Vaci
Have you got room to fit a header tank in your flat then run your hot
water from that?

It is called a "break tank" and in this case not a bright idea. The best is
a pump with a suitable non-return valve. The supply pipe is more than man
enough if it only supplies 2 or 3 flats.




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