Hello,

Does anyone know how you can increase hot water pressure without
increasing the tank size or position or increasing the pipe size. I
was thinking if there is pump that you could add to the hot water
supply to increase the speed of the hot water flow. This is for an
open vented system.

Many thanks
Arif

"harry" wrote in message
m...
Hello,

Does anyone know how you can increase hot water pressure without
increasing the tank size or position or increasing the pipe size. I
was thinking if there is pump that you could add to the hot water
supply to increase the speed of the hot water flow. This is for an
open vented system.

Many thanks
Arif

A normal central heating pump can be fitted in the outlet of the hot water tank
to increase the flow. But you need to fit a flow switch device that detects
when the water is being demanded so that the pump isn't running continually.


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On Mon, 24 May 2004 14:08:38 GMT, "BigWallop"
wrote:


"harry" wrote in message
om...
Hello,

Does anyone know how you can increase hot water pressure without
increasing the tank size or position or increasing the pipe size. I
was thinking if there is pump that you could add to the hot water
supply to increase the speed of the hot water flow. This is for an
open vented system.

Many thanks
Arif

A normal central heating pump can be fitted in the outlet of the hot water tank
to increase the flow. But you need to fit a flow switch device that detects
when the water is being demanded so that the pump isn't running continually.



Good idea in principle, but not using a standard CH pump which will
rust as a result of an ongoing flow of water with dissolved air.

For HW applications, Grundfos, among others make a brass pump and this
should be used.



..andy

To email, substitute .nospam with .gl

In article ,
BigWallop wrote:
A normal central heating pump can be fitted in the outlet of the hot
water tank to increase the flow.

Surely you need a bronze pump not a normal £30 one??

--
Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk
Free SEDBUK boiler database browser http://www.sda.co.uk/qsedbuk.htm

I was thinking if there is pump that you could add to the hot water
supply to increase the speed of the hot water flow. This is for an
open vented system.

Yes. It is called a single impellor shower pump. If you're pressurising the
whole house with it, get a good quality heavy duty type such as a Stuart
Turner Monsoon. Depending on the layout of the system and myriad other
factors, you may find the increased flow rate leads to air being sucked down
the vent tube. If this happens, and there is no obvious culprit like a half
closed feed valve to the cylinder, you will need to install a flange on the
system (or you might find turning the pump down fixes it). The flange will
normally eliminate the air effect provided it isn't too bad, although it
will effectively reduce the size of your cylinder slightly as the top of the
cylinder will become "dead" space.

Christian.

"Tony Bryer" wrote in message
...
In article ,
BigWallop wrote:
A normal central heating pump can be fitted in the outlet of the hot
water tank to increase the flow.

Surely you need a bronze pump not a normal £30 one??



To Andy and Tony.

I was only trying to help with the question the OP (Harry) posed, and the best
solution I thought of was a standard central heating pump with a flow switch
control arrangement. These standard pumps have lasted on our own system for
anything up to 10 years, so I was not under the impression that a materials
change to said pumps would create any massive increase to their performance or
longevity in these circumstances.

My thoughts are that the standard pump cost is small and the length of time it
lasts in this type of environment outweighs the costs of installing a more
expensive pump which gives such a small increase in the life span of the unit.
My research into the subject has shown me that the standard central heating pump
has a life span of up to 10 years, while the bronze units are rated as having a
life span of 12 years. To me, this small increase in the longevity does not
justify the greater increase in cost of installing this type of pump on to a
system which will not have a continual flow of aerated water, but will only
supply a small amount of water over very short periods of time.

The standard pumps are fine as long as they are installed in a position which
keeps them internally flooded. The water flow through the pump from a storage
cylinder is not interrupted by massive increases in aerated water, so the
impellor unit on a standard pump is more than capable of withstanding these
small deviations and will work quite happily for many years in this situation.

So, in summary, although I disagree with the suggestions you've made on the type
and construction materials of the pump required in the situation that the OP
(Harry) has, I will leave it to his own research into the matter to prove
otherwise.

The just of this posting is similar to a letter I have to compose to an
architect. Does it sound OK ?


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BigWallop wrote:

So, in summary, although I disagree with the suggestions you've made on the type
and construction materials of the pump required in the situation that the OP
(Harry) has

I think you've misunderstood the reasoning. In a CH system, the only
reason the iron/steel components (pump, rads, boiler water jacket etc.)
last more than a few months is that it's a closed system.

You start off with a set amount of water. In the first few weeks, all of
the oxygen in this water gets reacted out. The water by then has zero
dissolved oxygen, and is limited in the amount of corrosion it can cause.

But if you had a constant supply of fresh water the corrosion would
carry on at the same rate. Within a few months there weill be very
little iron left.


--
Grunff

On Mon, 24 May 2004 15:16:08 GMT, "BigWallop"
wrote:


"Tony Bryer" wrote in message
...
In article ,
BigWallop wrote:
A normal central heating pump can be fitted in the outlet of the hot
water tank to increase the flow.

Surely you need a bronze pump not a normal £30 one??



To Andy and Tony.

I was only trying to help with the question the OP (Harry) posed, and the best
solution I thought of was a standard central heating pump with a flow switch
control arrangement. These standard pumps have lasted on our own system for
anything up to 10 years, so I was not under the impression that a materials
change to said pumps would create any massive increase to their performance or
longevity in these circumstances.

My thoughts are that the standard pump cost is small and the length of time it
lasts in this type of environment outweighs the costs of installing a more
expensive pump which gives such a small increase in the life span of the unit.
My research into the subject has shown me that the standard central heating pump
has a life span of up to 10 years, while the bronze units are rated as having a
life span of 12 years.

The conditions are different though. The CH pump is in iron/steel
because it can be. The water is essentially anaerobic after a few
days - i.e. dissolved air is driven out. With the addition of
inhibitor, rusting can be essentially eliminated.


To me, this small increase in the longevity does not
justify the greater increase in cost of installing this type of pump on to a
system which will not have a continual flow of aerated water, but will only
supply a small amount of water over very short periods of time.

It will always be in contact with water containing quite a lot of
dissolved air, even if the water has stood in a roof tank for a few
hours, so it will deteriorate in a much smaller time period than 10
years.

The manufacturers make pumps for DHW and potable water use in bronze,
brass or plastic (or even stainless steel) for a reason......



The standard pumps are fine as long as they are installed in a position which
keeps them internally flooded. The water flow through the pump from a storage
cylinder is not interrupted by massive increases in aerated water, so the
impellor unit on a standard pump is more than capable of withstanding these
small deviations and will work quite happily for many years in this situation.

We're not talking about the water being grossly aerated because the
pump innards are partly out of water, though. Just having it in
contact will cause rusting quite nicely.



So, in summary, although I disagree with the suggestions you've made on the type
and construction materials of the pump required in the situation that the OP
(Harry) has, I will leave it to his own research into the matter to prove
otherwise.

The just of this posting is similar to a letter I have to compose to an
architect. Does it sound OK ?


Yes it does. What do you want him to do for you though?



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..andy

To email, substitute .nospam with .gl

"Andy Hall" wrote in message
...
On Mon, 24 May 2004 15:16:08 GMT, "BigWallop"
wrote:


"Tony Bryer" wrote in message
...
In article ,
BigWallop wrote:
snipped

(Harry) has, I will leave it to his own research into the matter to prove
otherwise.

The just of this posting is similar to a letter I have to compose to an
architect. Does it sound OK ?


Yes it does. What do you want him to do for you though?

.andy



The letter I need to write is about equipment that is going to be installed
alongside other electrical stuff that will cause interference on it, so I want
him to consider a change in the materials he wants used for the installation. I
know that the change will greatly increase the life span of the new equipment,
so I would like him to understand the benefits of changing it now before it's to
late.


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On Mon, 24 May 2004 15:53:55 GMT, "BigWallop"
wrote:





The letter I need to write is about equipment that is going to be installed
alongside other electrical stuff that will cause interference on it, so I want
him to consider a change in the materials he wants used for the installation. I
know that the change will greatly increase the life span of the new equipment,
so I would like him to understand the benefits of changing it now before it's to
late.


Ah, I see.

I wonder with architects how much skin they have in the game after the
project is complete though. Do they design for form or function?

Let's hope he doesn't do airport roofs......



..andy

To email, substitute .nospam with .gl

"Andy Hall" wrote in message
...
On Mon, 24 May 2004 15:53:55 GMT, "BigWallop"
wrote:





The letter I need to write is about equipment that is going to be installed
alongside other electrical stuff that will cause interference on it, so I
want
him to consider a change in the materials he wants used for the installation.
I
know that the change will greatly increase the life span of the new
equipment,
so I would like him to understand the benefits of changing it now before it's
to
late.


Ah, I see.

I wonder with architects how much skin they have in the game after the
project is complete though. Do they design for form or function?

Let's hope he doesn't do airport roofs......

.andy



This architect, a lady btw', has designed everything in this site, right down to
the head colours of the screws that hold the knobs on the doors, and the really
funny bit is, she sounds French and has the surname Le Boussier. So who knows
what else she's been involved in. :-))


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On Mon, 24 May 2004 16:26:20 +0100, Grunff wrote:

BigWallop wrote:

So, in summary, although I disagree with the suggestions you've made on the type
and construction materials of the pump required in the situation that the OP
(Harry) has

I think you've misunderstood the reasoning. In a CH system, the only
reason the iron/steel components (pump, rads, boiler water jacket etc.)
last more than a few months is that it's a closed system.

You start off with a set amount of water. In the first few weeks, all of
the oxygen in this water gets reacted out. The water by then has zero
dissolved oxygen, and is limited in the amount of corrosion it can cause.

But if you had a constant supply of fresh water the corrosion would
carry on at the same rate. Within a few months there weill be very
little iron left.

I have had mixed results with using iron pumps for DHW boosting and
circulation.
In two applications I replaced the previous iron with a new iron pump and
all was well. Perhaps the water heater had managed to undissolve all the air
from the water before it met the pump?
In the other application I was taken with the 'its wrong but its five times
cheaper and does the job' argument. I installed an iron pump only to have
to replace it with a bronze one a few weeks later due to discolouration of
the water.









--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html

On Mon, 24 May 2004 19:25:46 +0100, "Ed Sirett"
wrote:

On Mon, 24 May 2004 16:26:20 +0100, Grunff wrote:

BigWallop wrote:

So, in summary, although I disagree with the suggestions you've made on the type
and construction materials of the pump required in the situation that the OP
(Harry) has

I think you've misunderstood the reasoning. In a CH system, the only
reason the iron/steel components (pump, rads, boiler water jacket etc.)
last more than a few months is that it's a closed system.

You start off with a set amount of water. In the first few weeks, all of
the oxygen in this water gets reacted out. The water by then has zero
dissolved oxygen, and is limited in the amount of corrosion it can cause.

But if you had a constant supply of fresh water the corrosion would
carry on at the same rate. Within a few months there weill be very
little iron left.

I have had mixed results with using iron pumps for DHW boosting and
circulation.
In two applications I replaced the previous iron with a new iron pump and
all was well. Perhaps the water heater had managed to undissolve all the air
from the water before it met the pump?
In the other application I was taken with the 'its wrong but its five times
cheaper and does the job' argument. I installed an iron pump only to have
to replace it with a bronze one a few weeks later due to discolouration of
the water.

Hi,

Installing some sort of anode upstream by the pump could help, BES
part no. 12242 might do though it's zinc and not magnesium which is
better. A section of 22mm or 28mm pipe with a nice big lump of
magnesium fixed in it would do the trick.

Apparently these devices work for central heating systems too:

http://www.scalemaster.co.uk/hcc/hcc_physical_pages/hcc_physical_home.html

cheers,
Pete.

Good point about the flange. I've been researching these. I bought a 22mm
surrey flange from PlumbCenter, only to find it doesn't fit on the top of my
"Superlag" cylinder (from 1991). So I plan to make my own flange - I've
bought a 22mm/22mm/22mm Tee and a 22mm/15mm reducer. The T goes on top of
the cylinder. The reducer goes on top of the T. I can file the reducer's
insert limiter rim so I can push 15mm pipe all the way through it, and
through the attached 22mm T (so that it goes under the surface of the water
of the cylinder). It's not a surrey flange - the 'air free' and normal hot
water positions are exchanged. But a coupleof elbows and I can sort that.

You can hear the air in the cylinder if you bang it - and your can hear it
coming out the shower head. But I'm more concerned that without a flange the
pump will suck air down the expansion pipe, rather than out the cylinder!

I haven't ordered the shower pump yet, but I'll go for a Stuart Turner one.
Just 1 bar (that's 30ft head - plenty for me). I want a brass pump -
something that won't split open and flood my house out when I'm at work. The
plastic pumps from local DIY stores look too flimsy - I don't trust them -
the fittings look like garden hosepipe connectors.

Alistair.



"Christian McArdle" wrote in message
. net...
I was thinking if there is pump that you could add to the hot water
supply to increase the speed of the hot water flow. This is for an
open vented system.

Yes. It is called a single impellor shower pump. If you're pressurising
the
whole house with it, get a good quality heavy duty type such as a Stuart
Turner Monsoon. Depending on the layout of the system and myriad other
factors, you may find the increased flow rate leads to air being sucked
down
the vent tube. If this happens, and there is no obvious culprit like a
half
closed feed valve to the cylinder, you will need to install a flange on
the
system (or you might find turning the pump down fixes it). The flange will
normally eliminate the air effect provided it isn't too bad, although it
will effectively reduce the size of your cylinder slightly as the top of
the
cylinder will become "dead" space.

Christian.

"BigWallop" wrote in message ...
"harry" wrote in message
m...
Hello,

Does anyone know how you can increase hot water pressure without
increasing the tank size or position or increasing the pipe size. I
was thinking if there is pump that you could add to the hot water
supply to increase the speed of the hot water flow. This is for an
open vented system.

Many thanks
Arif

A normal central heating pump can be fitted in the outlet of the hot water tank
to increase the flow. But you need to fit a flow switch device that detects
when the water is being demanded so that the pump isn't running continually.


Great for the info, but can i ask, how low shoud the pump be position
from the hot water drain off from the cylinder, and where can i get a
flow switch device and where do you connect this device as well as
wiring such an item. And is it really necessary for a flange.

Appreciate the answer so far.

Arif


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(harry) wrote in
om:


Great for the info, but can i ask, how low shoud the pump be position
from the hot water drain off from the cylinder, and where can i get a
flow switch device and where do you connect this device as well as
wiring such an item. And is it really necessary for a flange.

Appreciate the answer so far.

Arif

Me, too, but I've got a question or two.

I started asking about installing a new h/w cylinder, moved on to a
nunvented cylinder, thence to heatbank, but they all seem a bit big and
ugly for me - and all I really want is a bit more flow on the hot water;
so I would like to think again about a vented cylinder plus pump.

But I'm worried about sucking air - surely if my manky flow is due to
lack of head, then pulling more out will mean that the header tank will
not be able to keep up, and air _will_ be sucked in, or am I missing
something?

I already use a pumped shower off my cold tank, and have no problem but
I'd have to empty the tank before I had trouble as I drain from the
bottom of the tank. And as the hot tank is closed it seems there might
be a problem.

However, I would love to give this a go as it seems more within my
capabilities, and stock heatbanks seem too big for my cupboard.

So can anyone help with the practicalities - the flow detector and how
to wire it; sketches for a practical system, etc?

I would like to use one pump to pressurise just two taps (its all the
hot taps I've got. If successful maybe to add a shower, but that seems
to be a whole new can of worms.

TIA

mike

On Tue, 25 May 2004 19:28:44 +0000 (UTC), mike ring
wrote:

(harry) wrote in
. com:


Great for the info, but can i ask, how low shoud the pump be position
from the hot water drain off from the cylinder, and where can i get a
flow switch device and where do you connect this device as well as
wiring such an item. And is it really necessary for a flange.

Appreciate the answer so far.

Arif

Me, too, but I've got a question or two.

I started asking about installing a new h/w cylinder, moved on to a
nunvented cylinder, thence to heatbank, but they all seem a bit big and
ugly for me - and all I really want is a bit more flow on the hot water;
so I would like to think again about a vented cylinder plus pump.

But I'm worried about sucking air - surely if my manky flow is due to
lack of head, then pulling more out will mean that the header tank will
not be able to keep up, and air _will_ be sucked in, or am I missing
something?


The key thing would be to make sure that the feed pipe which goes from
the tank to the bottom of the cylinder is large enough.

Probably at present it is in 22mm.

WHen I swapped out my cylinder, I replaced this run in 28mm.

Having enough bore on this pipe, means that it will be much less
likely for air to be sucked down the vent pipe and into the pump.

One other thing that is important is to avoid too many sharp elbows in
the pipe and ideally have none at all.
This can be done by renting a pipe bender (most that are cheaply
available only go up to 22mm, or alternatively what I did was to use
pairs of 135degree angles with a short length of straight pipe between
them. Not quite as good as a shallow bend but a lot better than a
90degree elbow.



I already use a pumped shower off my cold tank, and have no problem but
I'd have to empty the tank before I had trouble as I drain from the
bottom of the tank. And as the hot tank is closed it seems there might
be a problem.

However, I would love to give this a go as it seems more within my
capabilities, and stock heatbanks seem too big for my cupboard.

So can anyone help with the practicalities - the flow detector and how
to wire it; sketches for a practical system, etc?

You could use a flow switch (DPS have them for 22mm) and wire it in
series with a bronze pump or alternatively just use a single sided
shower pump.



I would like to use one pump to pressurise just two taps (its all the
hot taps I've got. If successful maybe to add a shower, but that seems
to be a whole new can of worms.

TIA

mike

..andy

To email, substitute .nospam with .gl

Andy Hall wrote in
:



You could use a flow switch (DPS have them for 22mm) and wire it in
series with a bronze pump or alternatively just use a single sided
shower pump.


Tahnks for the info Andy, I _was_ missing something.

A new cylinder plus pump seems more doable.

But what's DPS, please - I presume a supplier, but Google threw up
millions of Discount Plumbing Supplies/Services, but I couldn't find the
flow switch stockist, and other suppliers don't seem to have them.

But considering how well my Triton pumped shower goes, a shower pump
might well do; though I'd like to do it right.

In an earlier post you cautioned me against a 45 litre superduty
cylinder in case there was not enough in reserve

I have a 2 bed bungalow; only a small family could live here, and there
is only me and the mog; and we aren't anticipating company - do you
think 45, or possibly 80l is enough? I do quite fancy the mini tank.

Incidentally, how many litres does a hot bath require; any idea?

I appreciate all your help on this, your advice is really firming out
the plan

mike