Hi,

I've always had reasonable hot water pressure in my house from a hot
water tank in an airing cupboard in the bathroom fed from a plastic
cold water tank above it in the roof space.

I have replaced the sink in my kitchen, I now have one of those
swiveling mono taps which is connected to the hot water pipe by a
flexible braided tube that has a smaller internal diameter than 15mm
copper. There's also an inline mesh filter.

The flow of water has been reduced from a reasonable gushing to a
barely useful trickle.

I could fit a pump to boost the pressure but then it's just more
electrical power to consume and it will wear out and break down one
day.

So, why not improve the head to the tank? The cold water tank in the
roof is resting on wooden beams across the rafters. What if I raised
the height of the tank by placing more beams on the existing ones.
There's only a few pipes going to the tank and it's made of plastic, so
it would seem to be an easy job.

Does anyone know a formula to give the head from a known height. Eg.
how much higher would the tank have to be, before I notice an
improvement in the water pressure?

Thanks

On 25 May 2005 01:13:51 -0700, "Rob" wrote:



The flow of water has been reduced from a reasonable gushing to a
barely useful trickle.

Can the sink be refitted but without the flex?,the internal bore will
almost certainly be the main restriction. If you really want all round
gushing hot water,consider a pressurised hot water cylinder.
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The flexible hose comes with the tap. It is probably about 10mm in
external diameter which is the size of the hole in the base of the tap.
Which means that I can't use a biger pipe.

The base of the tap is only about 35mm in diameter, into which is
fitted hot & cold flexible hoses and a threaded rod that holds it all
in place. Hence the reason for the flexible hose being so small.
Obviously the cold water is mains pressure and altough reduced from the
tap, it is still reasonable.

"Rob" wrote in message
ups.com...
Hi,

I've always had reasonable hot water pressure in my house from a hot
water tank in an airing cupboard in the bathroom fed from a plastic
cold water tank above it in the roof space.

I have replaced the sink in my kitchen, I now have one of those
swiveling mono taps which is connected to the hot water pipe by a
flexible braided tube that has a smaller internal diameter than 15mm
copper. There's also an inline mesh filter.

The flow of water has been reduced from a reasonable gushing to a
barely useful trickle.

I could fit a pump to boost the pressure but then it's just more
electrical power to consume and it will wear out and break down one
day.

So, why not improve the head to the tank? The cold water tank in the
roof is resting on wooden beams across the rafters. What if I raised
the height of the tank by placing more beams on the existing ones.
There's only a few pipes going to the tank and it's made of plastic, so
it would seem to be an easy job.

Does anyone know a formula to give the head from a known height. Eg.
how much higher would the tank have to be, before I notice an
improvement in the water pressure?

Thanks

Its not hard to make the calculations - Assume a tank in the loft of a
typical two story house might be 4 metres above a kichen sink. If you could
lift it up 50 centimetres you would get 12.5% more head, or pressure. In a
bungalow it might be more worthwhile, as with a header tank only 2 metres
above the tap, a 50cm rise would give 25% more head. If you want pressures 1
metre of water exerts a pressure of 0.1 bar, or 1.4 lbs/sq in (excuse the
mixed units).

Perhaps more to the point, if the tap was working and the new one isn't, I
would investigate to check that there isn't a blockage somewhere in the
connections or the tap itself before trying anything else.

Andy

Does anyone know a formula to give the head from a known height. Eg.
how much higher would the tank have to be, before I notice an
improvement in the water pressure?

10m makes 1 bar. A mains pressure tap such as you've fitted usally requires
at least a bar, so the tank should be a bit over 10m above the tap (i.e.
kitchen on ground floor and tank on stilts in loft above a 3 storey house).
Allow an extra few metres for any double check valves, which may require you
to add on a storey or two. 1 bar is a minimum and won't provide particularly
powerful performance, either.

Christian.

"Andy Mckenzie" wrote in message
...
"Rob" wrote in message
ups.com...
Hi,

I've always had reasonable hot water pressure in my house from a hot
water tank in an airing cupboard in the bathroom fed from a plastic
cold water tank above it in the roof space.

I have replaced the sink in my kitchen, I now have one of those
swiveling mono taps which is connected to the hot water pipe by a
flexible braided tube that has a smaller internal diameter than 15mm
copper. There's also an inline mesh filter.

The flow of water has been reduced from a reasonable gushing to a
barely useful trickle.

I could fit a pump to boost the pressure but then it's just more
electrical power to consume and it will wear out and break down one
day.

So, why not improve the head to the tank? The cold water tank in the
roof is resting on wooden beams across the rafters. What if I raised
the height of the tank by placing more beams on the existing ones.
There's only a few pipes going to the tank and it's made of plastic, so
it would seem to be an easy job.

Does anyone know a formula to give the head from a known height. Eg.
how much higher would the tank have to be, before I notice an
improvement in the water pressure?

Thanks

Its not hard to make the calculations - Assume a tank in the loft of a
typical two story house might be 4 metres above a kichen sink. If you
could
lift it up 50 centimetres you would get 12.5% more head, or pressure. In a
bungalow it might be more worthwhile, as with a header tank only 2 metres
above the tap, a 50cm rise would give 25% more head. If you want pressures
1
metre of water exerts a pressure of 0.1 bar, or 1.4 lbs/sq in (excuse the
mixed units).

Perhaps more to the point, if the tap was working and the new one isn't, I
would investigate to check that there isn't a blockage somewhere in the
connections or the tap itself before trying anything else.

It appears a high pressure mixer was fitted. The type required is a low
pressure hot and high pressure cold. There usually a non-return valve in
the hot side.


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On 25 May 2005 01:30:01 -0700, Rob wrote:

The flexible hose comes with the tap. It is probably about 10mm in
external diameter which is the size of the hole in the base of the tap.
Which means that I can't use a biger pipe.

The base of the tap is only about 35mm in diameter, into which is
fitted hot & cold flexible hoses and a threaded rod that holds it all
in place. Hence the reason for the flexible hose being so small.
Obviously the cold water is mains pressure and altough reduced from the
tap, it is still reasonable.

I expect you have probably thought of this, but just in case....have you
checked the filter? We fitted one of these taps recently and it initially
didn't work well at all, turned out to be that the filter was clogged with
bits which had come from inside the pipework after all the plumbing
alterations. AFter discovering this I checked the bathroom basin tap which
has been slowly getting slower (!) and that one is much improved now too.
Just a thought.....


--
Holly, in France
Holiday home in Dordogne
http://la-plaine.chez.tiscali.fr

Rob I often find that the flexi tail has been squashed when fitting,check
that out first it can make quite a difference

Rob I often find that the flexi tail has been squashed when fitting,check
that out first it can make quite a difference

They particularly constrain themselves if they have been twisted, which
often happens when tightening an end.

Christian.

"Rob" wrote in news:1117008831.095128.93130
@z14g2000cwz.googlegroups.com:

Hi,

I could fit a pump to boost the pressure but then it's just more
electrical power to consume and it will wear out and break down one
day.

So, why not improve the head to the tank? The cold water tank in the
roof is resting on wooden beams across the rafters. What if I raised
the height of the tank by placing more beams on the existing ones.
There's only a few pipes going to the tank and it's made of plastic, so
it would seem to be an easy job.

BTDT, and raising the tank will not help:

I ended up using a booster pump, it's absolutely quiet, the pressure boost
is not enormous (Grundfos DHW booster), but it's made ahelluva difference
to the kitchen. It only runs when flow is required.

Also to the bath, though I hadn't many complaints there, it's 22mm nearly
all the way

mike