I am rebuilding a bathroom next year and beginning to scope it out. These
days finding taps that run on low pressure is quite difficult so I am
thinking of replacing the hot water cylinder with one that would take high
pressure and taking out the tank in the roof space. I presume it would
still be heated indirectly from the boiler which is 1.5 storeys below. That
would also solve a problem in the kitchen where the cold is on the mains and
the hot is on low pressure. At one time mixer taps were available where
this worked (eg KWC) - have they all gone now?

In the bathroom if this is too difficult/expensive I might keep the Ideal
Standard brassware - only 27 years old and working perfectly still.

Any pitfalls here?

On 14/12/2013 16:30, Geoff Pearson wrote:
I am rebuilding a bathroom next year and beginning to scope it out.
These days finding taps that run on low pressure is quite difficult so I
am thinking of replacing the hot water cylinder with one that would take
high pressure and taking out the tank in the roof space. I presume it
would still be heated indirectly from the boiler which is 1.5 storeys
below. That would also solve a problem in the kitchen where the cold is
on the mains and the hot is on low pressure. At one time mixer taps
were available where this worked (eg KWC) - have they all gone now?

In the bathroom if this is too difficult/expensive I might keep the
Ideal Standard brassware - only 27 years old and working perfectly still.

Any pitfalls here?


Cost.

You will have a pressure reducing valve (about 3.5 bar) which has a
release built in that will need running somewhere safe for water escapes.

The tank will have a relief valve that opens if it gets too hot or over
pressure this also needs to run somewhere safe for hot water to escape.

There will be an expansion vessel to locate between the pressure reducer
and the tank.

You can have one or more indirect coils to heat from the boiler or solar
or aga, etc.

Someone needs to check the safety devices occasionally.

"dennis@home" wrote in message
b.com...
On 14/12/2013 16:30, Geoff Pearson wrote:
I am rebuilding a bathroom next year and beginning to scope it out.
These days finding taps that run on low pressure is quite difficult so I
am thinking of replacing the hot water cylinder with one that would take
high pressure and taking out the tank in the roof space. I presume it
would still be heated indirectly from the boiler which is 1.5 storeys
below. That would also solve a problem in the kitchen where the cold is
on the mains and the hot is on low pressure. At one time mixer taps
were available where this worked (eg KWC) - have they all gone now?

In the bathroom if this is too difficult/expensive I might keep the
Ideal Standard brassware - only 27 years old and working perfectly still.

Any pitfalls here?


Cost.

You will have a pressure reducing valve (about 3.5 bar) which has a
release built in that will need running somewhere safe for water escapes.

The tank will have a relief valve that opens if it gets too hot or over
pressure this also needs to run somewhere safe for hot water to escape.

There will be an expansion vessel to locate between the pressure reducer
and the tank.

You can have one or more indirect coils to heat from the boiler or solar
or aga, etc.

Someone needs to check the safety devices occasionally.

Sounds roughly what I expected. £1000 if I get a plumber to do it? More?

On 14/12/2013 16:30, Geoff Pearson wrote:
I am rebuilding a bathroom next year and beginning to scope it out.
These days finding taps that run on low pressure is quite difficult so I
am thinking of replacing the hot water cylinder with one that would take
high pressure and taking out the tank in the roof space. I presume it
would still be heated indirectly from the boiler which is 1.5 storeys
below. That would also solve a problem in the kitchen where the cold is
on the mains and the hot is on low pressure. At one time mixer taps
were available where this worked (eg KWC) - have they all gone now?

Most kitchen taps these days are of a concentric spout design to avoid
this problem (and the need for non return valves to protect the rising main)

In the bathroom if this is too difficult/expensive I might keep the
Ideal Standard brassware - only 27 years old and working perfectly still.

Any pitfalls here?

From a use point of view, not really - you get good flow rates and
(near[1]) mains pressure hot and cold water all round the place.

Lots of detail he

http://wiki.diyfaq.org.uk/index.php?title=Unvented_DHW

However first ensure that you have adequate mains cold water flow rate
and pressure before doing away with the storage system.

From an installation and service point of view the cylinders cost a bit
more, but come with all the extra controls and stuff required to make
them work. They aught to the be serviced annually, although that is well
within the grasp of any moderately competent DIYer[1]. They often carry
10 year guarantees, but do require either naturally soft water, or that
a scale reduction device be fitted. You can heat them with immersion
heaters or indirect coils etc.

(people normally highlight that installing an unvented cylinder comes
under section G3 of the building regs, but now that applies to *all*
cylinders, unvented or otherwise[3] - so in that there is no difference.
If getting one installed professionally then its probably worth making
sure the installer knows what he is doing)


[1] Depending on your mains pressure - if its 0ver typically 3 to 3.5
bar then the PRV on the cylinder will limit it to that.

[2] Inspect the tundish to make sire there is no escape of water under
normal circumstances. Check the mains inlet filter, Check the operation
of the main over pressure and the over temp and over pressure relief
valves. Check the air pressure in the expansion vessel.

[3] Apart from small ones for basins etc.

--
Cheers,

John.

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

On 14/12/2013 17:59, Geoff Pearson wrote:

"dennis@home" wrote in message
b.com...
On 14/12/2013 16:30, Geoff Pearson wrote:
I am rebuilding a bathroom next year and beginning to scope it out.
These days finding taps that run on low pressure is quite difficult so I
am thinking of replacing the hot water cylinder with one that would take
high pressure and taking out the tank in the roof space. I presume it
would still be heated indirectly from the boiler which is 1.5 storeys
below. That would also solve a problem in the kitchen where the cold is
on the mains and the hot is on low pressure. At one time mixer taps
were available where this worked (eg KWC) - have they all gone now?

In the bathroom if this is too difficult/expensive I might keep the
Ideal Standard brassware - only 27 years old and working perfectly
still.

Any pitfalls here?


Cost.

You will have a pressure reducing valve (about 3.5 bar) which has a
release built in that will need running somewhere safe for water escapes.

The tank will have a relief valve that opens if it gets too hot or
over pressure this also needs to run somewhere safe for hot water to
escape.

There will be an expansion vessel to locate between the pressure
reducer and the tank.

You can have one or more indirect coils to heat from the boiler or
solar or aga, etc.

Someone needs to check the safety devices occasionally.

Sounds roughly what I expected. £1000 if I get a plumber to do it? More?

Depends on what size cylinder you want, and how much work is involved...
generally speaking you can usually do it by mostly reusing existing
pipework. You will need one new run for the discharge pipe.

I paid about £840 for a 250L [1] unistor from a local plumbers
merchant...That comes with all the extra bits including an additional
Honeywell 2 port motorised valve.

[1] Work out what size you need:

http://wiki.diyfaq.org.uk/index.php?...water_cylinder

--
Cheers,

John.

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

In article ,
Geoff Pearson wrote:
I am rebuilding a bathroom next year and beginning to scope it out.
These days finding taps that run on low pressure is quite difficult so
I am thinking of replacing the hot water cylinder with one that would
take high pressure and taking out the tank in the roof space. I
presume it would still be heated indirectly from the boiler which is
1.5 storeys below. That would also solve a problem in the kitchen where
the cold is on the mains and the hot is on low pressure. At one time
mixer taps were available where this worked (eg KWC) - have they all
gone now?

In the bathroom if this is too difficult/expensive I might keep the
Ideal Standard brassware - only 27 years old and working perfectly
still.

Any pitfalls here?

Might be easier to simply add a pump.

--
*Some people are alive only because it's illegal to kill them *

Dave Plowman London SW
To e-mail, change noise into sound.

"Geoff Pearson" wrote in message
...
I am rebuilding a bathroom next year and beginning to scope it out. These
days finding taps that run on low pressure is quite difficult so I am
thinking of replacing the hot water cylinder with one that would take high
pressure and taking out the tank in the roof space. I presume it would
still be heated indirectly from the boiler which is 1.5 storeys below. That
would also solve a problem in the kitchen where the cold is on the mains
and the hot is on low pressure. At one time mixer taps were available
where this worked (eg KWC) - have they all gone now?

In the bathroom if this is too difficult/expensive I might keep the Ideal
Standard brassware - only 27 years old and working perfectly still.

Any pitfalls here?


You would be better to keep what you've got.
There are no advantages to changing over unless you like high pressure
showers.
If your incoming mains water pipe is crudded up, you may well find it takes
forever to fill the bath with a mains pressure hot water tank.
Also you would have moving parts that need to be maintained.

"harryagain" wrote in message
...

"Geoff Pearson" wrote in message
...
I am rebuilding a bathroom next year and beginning to scope it out. These
days finding taps that run on low pressure is quite difficult so I am
thinking of replacing the hot water cylinder with one that would take high
pressure and taking out the tank in the roof space. I presume it would
still be heated indirectly from the boiler which is 1.5 storeys below.
That would also solve a problem in the kitchen where the cold is on the
mains and the hot is on low pressure. At one time mixer taps were
available where this worked (eg KWC) - have they all gone now?

In the bathroom if this is too difficult/expensive I might keep the Ideal
Standard brassware - only 27 years old and working perfectly still.

Any pitfalls here?


You would be better to keep what you've got.
There are no advantages to changing over unless you like high pressure
showers.
If your incoming mains water pipe is crudded up, you may well find it
takes forever to fill the bath with a mains pressure hot water tank.
Also you would have moving parts that need to be maintained.


I am gently coming to that conclusion. The water main is fine - the water
pressure is huge - and we have soft water so it does not crud up and was
renewed in plastic in 1987 (with a big grant from the Council).

On 15/12/2013 11:52, Geoff Pearson wrote:

"harryagain" wrote in message
...

"Geoff Pearson" wrote in message
...
I am rebuilding a bathroom next year and beginning to scope it out.
These days finding taps that run on low pressure is quite difficult
so I am thinking of replacing the hot water cylinder with one that
would take high pressure and taking out the tank in the roof space.
I presume it would still be heated indirectly from the boiler which
is 1.5 storeys below. That would also solve a problem in the kitchen
where the cold is on the mains and the hot is on low pressure. At
one time mixer taps were available where this worked (eg KWC) - have
they all gone now?

In the bathroom if this is too difficult/expensive I might keep the
Ideal Standard brassware - only 27 years old and working perfectly
still.

Any pitfalls here?


You would be better to keep what you've got.
There are no advantages to changing over unless you like high pressure
showers.

As usual harry is, at best, over simplifying. There can be plenty of
advantages when a system is installed in appropriate circumstances.

If your incoming mains water pipe is crudded up, you may well find it
takes forever to fill the bath with a mains pressure hot water tank.

Alternatively you may find with a decent main supply that bath fills
become much faster...

Also you would have moving parts that need to be maintained.


I am gently coming to that conclusion. The water main is fine - the
water pressure is huge - and we have soft water so it does not crud up
and was renewed in plastic in 1987 (with a big grant from the Council).

In one sense then you have the ideal setup for mains pressure hot water,
so it really depends on how well the existing system performs, and what
you are attempting to achieve.

In my case there was no contest, the gravity fed system I had previously
was hopeless and completely unsuited to the property. What I have now
has has proved to be the best hot water system I have ever used, and
outclasses the previous in every respect. However that is not going to
be the same for everyone.


--
Cheers,

John.

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

John Rumm wrote:
On 15/12/2013 11:52, Geoff Pearson wrote:

"harryagain" wrote in message
...

"Geoff Pearson" wrote in message
...
I am rebuilding a bathroom next year and beginning to scope it out.
These days finding taps that run on low pressure is quite difficult
so I am thinking of replacing the hot water cylinder with one that
would take high pressure and taking out the tank in the roof space.
I presume it would still be heated indirectly from the boiler which
is 1.5 storeys below. That would also solve a problem in the kitchen
where the cold is on the mains and the hot is on low pressure. At
one time mixer taps were available where this worked (eg KWC) - have
they all gone now?

In the bathroom if this is too difficult/expensive I might keep the
Ideal Standard brassware - only 27 years old and working perfectly
still.

Any pitfalls here?


You would be better to keep what you've got.
There are no advantages to changing over unless you like high pressure
showers.

As usual harry is, at best, over simplifying. There can be plenty of
advantages when a system is installed in appropriate circumstances.

If your incoming mains water pipe is crudded up, you may well find it
takes forever to fill the bath with a mains pressure hot water tank.

Alternatively you may find with a decent main supply that bath fills become much faster...

Also you would have moving parts that need to be maintained.


I am gently coming to that conclusion. The water main is fine - the
water pressure is huge - and we have soft water so it does not crud up
and was renewed in plastic in 1987 (with a big grant from the Council).

In one sense then you have the ideal setup for mains pressure hot water,
so it really depends on how well the existing system performs, and what
you are attempting to achieve.

In my case there was no contest, the gravity fed system I had previously
was hopeless and completely unsuited to the property. What I have now has
has proved to be the best hot water system I have ever used, and
outclasses the previous in every respect. However that is not going to be
the same for everyone.



I've often wondered if there is a good way to safely and legally boost an
existing HW tank to work much nearer its rated maximum pressure. Most
vented tanks I think are rated to at least 1bar and that would give a
useful boost to most systems if you could get the header tank high enough
(which in most cases of course you never can - flats excepted).

I guess the problem is providing a fail safe pressure relief system.

Tim

On 15/12/2013 22:18, Tim+ wrote:
John Rumm wrote:
On 15/12/2013 11:52, Geoff Pearson wrote:

"harryagain" wrote in message
...

"Geoff Pearson" wrote in message
...
I am rebuilding a bathroom next year and beginning to scope it out.
These days finding taps that run on low pressure is quite difficult
so I am thinking of replacing the hot water cylinder with one that
would take high pressure and taking out the tank in the roof space.
I presume it would still be heated indirectly from the boiler which
is 1.5 storeys below. That would also solve a problem in the kitchen
where the cold is on the mains and the hot is on low pressure. At
one time mixer taps were available where this worked (eg KWC) - have
they all gone now?

In the bathroom if this is too difficult/expensive I might keep the
Ideal Standard brassware - only 27 years old and working perfectly
still.

Any pitfalls here?


You would be better to keep what you've got.
There are no advantages to changing over unless you like high pressure
showers.

As usual harry is, at best, over simplifying. There can be plenty of
advantages when a system is installed in appropriate circumstances.

If your incoming mains water pipe is crudded up, you may well find it
takes forever to fill the bath with a mains pressure hot water tank.

Alternatively you may find with a decent main supply that bath fills become much faster...

Also you would have moving parts that need to be maintained.


I am gently coming to that conclusion. The water main is fine - the
water pressure is huge - and we have soft water so it does not crud up
and was renewed in plastic in 1987 (with a big grant from the Council).

In one sense then you have the ideal setup for mains pressure hot water,
so it really depends on how well the existing system performs, and what
you are attempting to achieve.

In my case there was no contest, the gravity fed system I had previously
was hopeless and completely unsuited to the property. What I have now has
has proved to be the best hot water system I have ever used, and
outclasses the previous in every respect. However that is not going to be
the same for everyone.



I've often wondered if there is a good way to safely and legally boost an
existing HW tank to work much nearer its rated maximum pressure. Most
vented tanks I think are rated to at least 1bar and that would give a
useful boost to most systems if you could get the header tank high enough
(which in most cases of course you never can - flats excepted).

I guess the problem is providing a fail safe pressure relief system.

Tim


You put a pump on the outlet.

In message

rnal-september.org, Tim+ writes


I've often wondered if there is a good way to safely and legally boost an
existing HW tank to work much nearer its rated maximum pressure. Most
vented tanks I think are rated to at least 1bar and that would give a
useful boost to most systems if you could get the header tank high enough
(which in most cases of course you never can - flats excepted).


You build a really tall tower in your garden with the cold water cistern
on top?

I guess the problem is providing a fail safe pressure relief system.

Well yes, but surely the main problem is having a way to increase the
pressure? I guess you could always connect it up to the mains....

I think there is a reason people pump the outlet :-)
--
Chris French

chris French wrote:
In message
rnal-september.org, Tim+ writes


I've often wondered if there is a good way to safely and legally boost an
existing HW tank to work much nearer its rated maximum pressure. Most
vented tanks I think are rated to at least 1bar and that would give a
useful boost to most systems if you could get the header tank high enough
(which in most cases of course you never can - flats excepted).


You build a really tall tower in your garden with the cold water cistern on top?

I guess the problem is providing a fail safe pressure relief system.

Well yes, but surely the main problem is having a way to increase the
pressure? I guess you could always connect it up to the mains....

I think there is a reason people pump the outlet :-)

Pumps are noisy and relatively expensive. A mains pressure regulator is
cheap and quiet. I'm trying to work out whether a long coil laid on its
side and with each loop of the coil half filled could provide the necessary
"height" but in a compact space for the overflow. Getting 30 ft of height
into a coil might need a lot of pipe though!

Tim

On Monday, December 16, 2013 10:20:42 AM UTC, Tim+ wrote:
chris French wrote:

In message

rnal-september.org, Tim+ writes





I've often wondered if there is a good way to safely and legally boost an

existing HW tank to work much nearer its rated maximum pressure. Most

vented tanks I think are rated to at least 1bar and that would give a

useful boost to most systems if you could get the header tank high enough

(which in most cases of course you never can - flats excepted).





You build a really tall tower in your garden with the cold water cistern on top?



I guess the problem is providing a fail safe pressure relief system.



Well yes, but surely the main problem is having a way to increase the

pressure? I guess you could always connect it up to the mains....



I think there is a reason people pump the outlet :-)



Pumps are noisy and relatively expensive. A mains pressure regulator is

cheap and quiet. I'm trying to work out whether a long coil laid on its

side and with each loop of the coil half filled could provide the necessary

"height" but in a compact space for the overflow. Getting 30 ft of height

into a coil might need a lot of pipe though!



Tim

What ?

I think you've got hold of the wrong end of the stick. Its the height, and gravity, that give the benefit. Not the length of the run

In message

rnal-september.org, Tim+ writes
chris French wrote:
In message
te
rnal-september.org, Tim+ writes


I've often wondered if there is a good way to safely and legally boost an
existing HW tank to work much nearer its rated maximum pressure. Most
vented tanks I think are rated to at least 1bar and that would give a
useful boost to most systems if you could get the header tank high enough
(which in most cases of course you never can - flats excepted).


You build a really tall tower in your garden with the cold water
cistern on top?

I guess the problem is providing a fail safe pressure relief system.

Well yes, but surely the main problem is having a way to increase the
pressure? I guess you could always connect it up to the mains....

I think there is a reason people pump the outlet :-)

Pumps are noisy and relatively expensive. A mains pressure regulator is
cheap and quiet.

I'm trying to work out whether a long coil laid on its
side and with each loop of the coil half filled could provide the necessary
"height" but in a compact space for the overflow. Getting 30 ft of height
into a coil might need a lot of pipe though!

What !?

It's the physical height that's important, how would half filled coils
of pipe exert any extra head?
--
Chris French

chris French wrote:
In message
rnal-september.org, Tim+ writes
chris French wrote:
In message te
rnal-september.org, Tim+ writes


I've often wondered if there is a good way to safely and legally boost an
existing HW tank to work much nearer its rated maximum pressure. Most
vented tanks I think are rated to at least 1bar and that would give a
useful boost to most systems if you could get the header tank high enough
(which in most cases of course you never can - flats excepted).


You build a really tall tower in your garden with the cold water cistern on top?

I guess the problem is providing a fail safe pressure relief system.

Well yes, but surely the main problem is having a way to increase the
pressure? I guess you could always connect it up to the mains....

I think there is a reason people pump the outlet :-)

Pumps are noisy and relatively expensive. A mains pressure regulator is
cheap and quiet.

I'm trying to work out whether a long coil laid on its
side and with each loop of the coil half filled could provide the necessary
"height" but in a compact space for the overflow. Getting 30 ft of height
into a coil might need a lot of pipe though!

What !?

It's the physical height that's important, how would half filled coils of
pipe exert any extra head?

Ditch the header tank. Connect c/w tank to mains via pressure reducing
valve set to 1 bar say. As it's a vented tank you would need a 32 foot
high expansion pipe to prevent it just pouring out the expansion pipe (and
to stay legal).

Given that that isn't terribly practical, I'm hypothesising whether a
vertical coil with say, 32 one foot high segments of water separated by air
would exert the same back pressure.

All I know for sure is that an air locked coil of hosepipe if held
vertically seems to take a lot more pressure than you'd think to expel the
air & water than you'd assume from the simple diameter of the coil. The
air locked sections seem to be additive in their resistance.

Tim

In article
,
Tim+ wrote:
Well yes, but surely the main problem is having a way to increase the
pressure? I guess you could always connect it up to the mains....

I think there is a reason people pump the outlet :-)

Pumps are noisy and relatively expensive.

Compared to changing a standard cylinder for a mains pressure one? And all
the additional work?

A mains pressure regulator is
cheap and quiet. I'm trying to work out whether a long coil laid on its
side and with each loop of the coil half filled could provide the
necessary "height" but in a compact space for the overflow. Getting 30
ft of height into a coil might need a lot of pipe though!

--
*I see you've set aside this special time to humiliate yourself in public

Dave Plowman London SW
To e-mail, change noise into sound.

Dave Plowman (News) wrote:
In article
,
Tim+ wrote:
Well yes, but surely the main problem is having a way to increase
the pressure? I guess you could always connect it up to the
mains....

I think there is a reason people pump the outlet :-)

Pumps are noisy and relatively expensive.

Compared to changing a standard cylinder for a mains pressure one?
And all the additional work?

Go back and read what I wrote. I'm talking about using the pressure
capabilities of your existing conventional vented cylinder.

As I said, I think most of are rated to at least one bar (some are higher)
and boosting the system pressure to that level would give an appreciably
improved HW flow to most systems.

Tim

On Sunday, December 15, 2013 10:18:44 PM UTC, Tim+ wrote:


I've often wondered if there is a good way to safely and legally boost an
existing HW tank to work much nearer its rated maximum pressure. Most
vented tanks I think are rated to at least 1bar and that would give a
useful boost to most systems if you could get the header tank high enough
(which in most cases of course you never can - flats excepted).

Makes sure the header tank is really at the highest point in the roof space. Often people install them more conveniently lower down resulting in less pressure.

Robert

"Tim+" wrote in message
...
Dave Plowman (News) wrote:
In article
,
Tim+ wrote:
Well yes, but surely the main problem is having a way to increase
the pressure? I guess you could always connect it up to the
mains....

I think there is a reason people pump the outlet :-)

Pumps are noisy and relatively expensive.

Compared to changing a standard cylinder for a mains pressure one?
And all the additional work?

Go back and read what I wrote. I'm talking about using the pressure
capabilities of your existing conventional vented cylinder.

As I said, I think most of are rated to at least one bar (some are higher)
and boosting the system pressure to that level would give an appreciably
improved HW flow to most systems.


I have seen (some foriegn place) the expansion pipe taken right up
projecting beyond the top of the chimney. (With return bend on top) Galv.
Pipe
There was a reducing valve on the inlet.
If it stuck, the water came out of the top & ran down the roof.
I think the pressure was about 2bar so about 30ft head.
Galv. steel hot water tank I seem to remember. Rivetted.

Hey, you could also use it for your TV aerial as well.

On Sunday, December 15, 2013 10:18:44 PM UTC, Tim+ wrote:
John Rumm wrote:

I've often wondered if there is a good way to safely and legally boost an

existing HW tank to work much nearer its rated maximum pressure. Most

vented tanks I think are rated to at least 1bar and that would give a

useful boost to most systems if you could get the header tank high enough

(which in most cases of course you never can - flats excepted).

You could with a Pressure reducing valve and Safety valve(s).
It's living dangerously, though. Domestic hot water tanks are paper thin and neither valve is particularly reliable or precise.
It's an unvented cylinder and you should have the G3 ticket to install them.
It should also be a factory assembled kit.

An immersion heater would introduce a whole new range of potential excitement.
Some unvented cylinders work like this (Tribune ISTR???) but the copper cylinders are/were more robust.

Stainless steel cylinders are now more common, given the price of copper.