The shower in my (1930 built) house is fed direct from the bath taps.
The hot water cyliner is in the airing cupboard.

The hot water pressure is very low, not just in the bathroom but in the
kitchen as well.

This makes the shower difficult to use as mixing even a small quantity
of cold water with the hot makes the shower go cold.

Should I fit a pump somewhere to boost the flow of hot water from the
cylinder? If so, where?

In an earlier contribution to this discussion,
Stevethefootycoach wrote:

The shower in my (1930 built) house is fed direct from the bath taps.
The hot water cyliner is in the airing cupboard.

The hot water pressure is very low, not just in the bathroom but in
the kitchen as well.

This makes the shower difficult to use as mixing even a small quantity
of cold water with the hot makes the shower go cold.

Should I fit a pump somewhere to boost the flow of hot water from the
cylinder? If so, where?


A pump located under the bath would be a possibility. *But* you will also
need to plumb in a low pressure cold feed from the cold header tank rather
than using mains. The 2-gang pump will then receive hot and cold at roughly
the *same* pressure, and boost them both equally so that your mixer shower
will work properly.

The purists will also tell you that you should take the hot feed from a
Surrey or Essex flange installed in the hot cylinder rather than just using
the default take-off at the top. However, you can probably get away without
doing that - as I do.
--
Cheers,
Roger
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spam.

Thanks Roger.

does the Surrey/Essex flange boost the pressure of the hot water?

In an earlier contribution to this discussion,
Stevethefootycoach wrote:

Thanks Roger.

does the Surrey/Essex flange boost the pressure of the hot water?

No. It just takes the water from a bit lower down in the cylinder.
Otherwise, if you have a very powerful pump, it can suck water - followed by
air - from the vent pipe, rather than water from the cylinder. A flange
prevents this - but isn't always necessary, depending on the power and
location of the pump.
--
Cheers,
Roger
______
Please reply to newsgroup.
Reply address IS valid, but is disposable in the event of excessive
spam.

A pump located under the bath would be a possibility. *But* you will also
need to plumb in a low pressure cold feed from the cold header tank rather
than using mains.

Actually, provided you use a pressure balanced mixer, it is entirely
possible to mix mains cold water with pumped hot water. You simply need a
good mains flow rate and a single impellor pump. I fitted such a system into
my last house and it worked admirably.

In fact, even without a pressure balanced mixer, it will probably still work
very well, but may be a little sensitive to other taps/toilets being used in
the house.

The purists will also tell you that you should take the hot feed from a
Surrey or Essex flange installed in the hot cylinder rather than just
using
the default take-off at the top. However, you can probably get away
without
doing that - as I do.

Indeed. I fitted mine without a flange, but understood that one might be
required if it sucked air. It didn't. However, my cold tank was directly
above the cylinder with flowed bends. A 15mm tortuous feed with elbows would
be another matter.

The best place for the pump is need the cylinder, as they prefer to push
rather than pull. It also means that the kitchen hot tap gets pumped
operation, too.

Christian.

"Christian McArdle" wrote in message
.. .
A pump located under the bath would be a possibility. *But* you will also
need to plumb in a low pressure cold feed from the cold header tank
rather
than using mains.

Actually, provided you use a pressure balanced mixer, it is entirely
possible to mix mains cold water with pumped hot water. You simply need a
good mains flow rate and a single impellor pump. I fitted such a system
into
my last house and it worked admirably.

In fact, even without a pressure balanced mixer, it will probably still
work
very well, but may be a little sensitive to other taps/toilets being used
in
the house.

The purists will also tell you that you should take the hot feed from a
Surrey or Essex flange installed in the hot cylinder rather than just
using
the default take-off at the top. However, you can probably get away
without
doing that - as I do.

Indeed. I fitted mine without a flange, but understood that one might be
required if it sucked air. It didn't. However, my cold tank was directly
above the cylinder with flowed bends. A 15mm tortuous feed with elbows
would
be another matter.

The best place for the pump is need the cylinder, as they prefer to push
rather than pull. It also means that the kitchen hot tap gets pumped
operation, too.

Using a pipe stat and return loop pipe on the DHW draw-off back to the
cylinder, a secondary circulation loop can be added very easily using the
same pump. The return pipe only need be very small bore plastic to thread
through joist, etc, just like cable.

Using a pipe stat and return loop pipe on the DHW draw-off back to the
cylinder, a secondary circulation loop can be added very easily using the
same pump. The return pipe only need be very small bore plastic to thread
through joist, etc, just like cable.

In fact, you would want it very thin, as you don't want the secondary flow
to reduce the outlet pressure. Obviously, you can also balance it down with
some sort of valve, too.

I can't help thinking that a single impellor shower pump would be too noisy
for a secondary loop installation, though. Some might not like the low flow
rate and high pressure drop when no outlets are open.

Christian.

"Christian McArdle" wrote in message
.. .
Using a pipe stat and return loop pipe on the DHW draw-off back to the
cylinder, a secondary circulation loop can be added very easily using the
same pump. The return pipe only need be very small bore plastic to
thread
through joist, etc, just like cable.

In fact, you would want it very thin, as you don't want the secondary flow
to reduce the outlet pressure. Obviously, you can also balance it down
with
some sort of valve, too.

I can't help thinking that a single impellor shower pump would be too
noisy
for a secondary loop installation, though. Some might not like the low
flow
rate and high pressure drop when no outlets are open.

Christian.

The Grundfos Booster is quiet. It looks like a normal CH pump.
http://www.heatweb.com/
Scroll to the very bottom.

Stevethefootycoach wrote:

The hot water pressure is very low, not just in the bathroom but in the
kitchen as well.

This makes the shower difficult to use as mixing even a small quantity
of cold water with the hot makes the shower go cold.

It sounds like you have gravity fed hot and mains cold at the bath. If
this is the case you may be able to help the situation with a single
impeller pump bosting just the hot. The better but more difficult
alternative would be installing a new dedicated cold feed from the cold
water tank and using a dual impeller shower pump.


--
Cheers,

John.

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

This sounds like a good idea.

Is it just a case of fitting a single impeller pump in line with the
hot water cylinder outlet? That would (presumably) boost the hot water
pressure to all taps in the house. Or should I fit the pump in line
with the feed to the bath/shower?

In an earlier contribution to this discussion,
Stevethefootycoach wrote:

This sounds like a good idea.

Is it just a case of fitting a single impeller pump in line with the
hot water cylinder outlet? That would (presumably) boost the hot water
pressure to all taps in the house. Or should I fit the pump in line
with the feed to the bath/shower?

This is an alternative to the twin-impellor pump which I suggested earlier,
and involves less plumbing, but doesn't give equal hot and cold pressures -
which may or may not matter.

As far as location is concerned, you can choose how many of the hot taps you
wish to boost, and put it in an appropriate place to achieve this. The pump
will probably be heard throughout the house - which may be a consideration.

[The normal way in which these pumps work is that they have a flow switch,
which detects (gravity) flow when you open a tap, and switches on the pump.
When you close the tap, the flow stops and the pump is automatically
switched off].
--
Cheers,
Roger
______
Please reply to newsgroup.
Reply address IS valid, but is disposable in the event of excessive
spam.

"Roger Mills (aka Set Square)" wrote in message
...
In an earlier contribution to this discussion,
Stevethefootycoach wrote:

This sounds like a good idea.

Is it just a case of fitting a single impeller pump in line with the hot
water cylinder outlet? That would (presumably) boost the hot water
pressure to all taps in the house. Or should I fit the pump in line with
the feed to the bath/shower?

This is an alternative to the twin-impellor pump which I suggested
earlier, and involves less plumbing, but doesn't give equal hot and cold
pressures - which may or may not matter.

If you read and understood Christian's post this would all be clear. Using
one in-line pump on the DHW draw-off of a low pressure cylinder and the cold
to all taps via the mains can give equal pressure at the taps for mixing.
You install a 22mm pressure equalising valve after the pump, then both hot
and cold lines are at equal pressure. You could fit a few 15mm equalisation
valves on a few lines rather than a 22mm valve.

Assume: the pump gives out 1 bar, the mains 2.5 bar. When you turn on the
cold tap 2.5 bar is there. Then you turn on the hot and the cold drops to
the same pressure as the hot that is flowing through the equalisation valve.
If someone flushes a toilet and the cold mains pressure does not drop below
1 bar, then no affect.

The idea is not to have an adverse effect on the shower mixer, the most
critical part of the water system. If a separate shower en-suite shower and
someone turns on a bath tap then the pressure is going to drop along the
pumped DHW line. It mat be best to take the bath from the top of the
cylinder and the rest of the taps and shower from a Surrey flange. Then the
bath will not affect the pumped supply. If the bath water from the mains
then fix a low pressure hot water mixer on the bath

As far as location is concerned, you can choose how many of the hot taps
you wish to boost, and put it in an appropriate place to achieve this. The
pump will probably be heard throughout the house - which may be a
consideration.

The Grundfos single impeller Booster pump is quiet, and cheap (about £80)
its selling point.

[The normal way in which these pumps work is that they have a flow switch,
which detects (gravity) flow when you open a tap, and switches on the
pump. When you close the tap, the flow stops and the pump is automatically
switched off].

Thank you all for your quick and useful replies.

I'll put a single impeller pump on the outlet side of the hot water
cylinder and let you know how it goes.

thanks again!

Doctor Drivel wrote:
"Roger Mills (aka Set Square)" wrote in message
...
In an earlier contribution to this discussion,
Stevethefootycoach wrote:

This sounds like a good idea.

Is it just a case of fitting a single impeller pump in line with the hot
water cylinder outlet? That would (presumably) boost the hot water
pressure to all taps in the house. Or should I fit the pump in line with
the feed to the bath/shower?

This is an alternative to the twin-impellor pump which I suggested
earlier, and involves less plumbing, but doesn't give equal hot and cold
pressures - which may or may not matter.

If you read and understood Christian's post this would all be clear. Using
one in-line pump on the DHW draw-off of a low pressure cylinder and the cold
to all taps via the mains can give equal pressure at the taps for mixing.
You install a 22mm pressure equalising valve after the pump, then both hot
and cold lines are at equal pressure. You could fit a few 15mm equalisation
valves on a few lines rather than a 22mm valve.

Assume: the pump gives out 1 bar, the mains 2.5 bar. When you turn on the
cold tap 2.5 bar is there. Then you turn on the hot and the cold drops to
the same pressure as the hot that is flowing through the equalisation valve.
If someone flushes a toilet and the cold mains pressure does not drop below
1 bar, then no affect.

The idea is not to have an adverse effect on the shower mixer, the most
critical part of the water system. If a separate shower en-suite shower and
someone turns on a bath tap then the pressure is going to drop along the
pumped DHW line. It mat be best to take the bath from the top of the
cylinder and the rest of the taps and shower from a Surrey flange. Then the
bath will not affect the pumped supply. If the bath water from the mains
then fix a low pressure hot water mixer on the bath

As far as location is concerned, you can choose how many of the hot taps
you wish to boost, and put it in an appropriate place to achieve this. The
pump will probably be heard throughout the house - which may be a
consideration.

The Grundfos single impeller Booster pump is quiet, and cheap (about £80)
its selling point.

[The normal way in which these pumps work is that they have a flow switch,
which detects (gravity) flow when you open a tap, and switches on the
pump. When you close the tap, the flow stops and the pump is automatically
switched off].

Thanks for that IMM and Christian. This Grundfos pump sounds a god
alternative to a big power shower pump. Another post to be saved.