Since 1992 my friend has had an impossible to control shower which
drives his family (daughter especially) and visitors mad.

It is difficult to believe that given the installation no improvements
were suggested when the Greenstar 28i Junior was installed 7 years
ago.

The shower is on the first floor. The tap is one of those old
fashioned two-into-one with a plunger to change the destination from
down into the bath to up to the shower head.

The hot water is fed at mains pressure, the cold is from a header tank
in the attic directly above, which by my calculations means that cold
water will never make it to the shower head.

On my visit last week I suggested that we simply turn the hot water
temperature down - but no, unlike my (older) boiler there is no
separate control, despite no mention of this in the (on-line) manual.

The guy who posted this:
http://forums.moneysavingexpert.com/....php?t=3584437

seems to have the exact same issue.

My immediate thought is to take a feed from the inlet of the header
tank and connect to the bath's cold water, giving it mains pressure.

Any thoughts?

--
AnthonyL

On Fri, 10 Mar 2017 11:56:14 +0000, AnthonyL wrote:

Since 1992 my friend has had an impossible to control shower which
drives his family (daughter especially) and visitors mad.

It is difficult to believe that given the installation no improvements
were suggested when the Greenstar 28i Junior was installed 7 years ago.

The shower is on the first floor. The tap is one of those old fashioned
two-into-one with a plunger to change the destination from down into the
bath to up to the shower head.

The hot water is fed at mains pressure, the cold is from a header tank
in the attic directly above, which by my calculations means that cold
water will never make it to the shower head.

On my visit last week I suggested that we simply turn the hot water
temperature down - but no, unlike my (older) boiler there is no separate
control, despite no mention of this in the (on-line) manual.

The guy who posted this:
http://forums.moneysavingexpert.com/....php?t=3584437

seems to have the exact same issue.

My immediate thought is to take a feed from the inlet of the header tank
and connect to the bath's cold water, giving it mains pressure.

Any thoughts?

As far as I am aware you should never mix tank and mains pressure at a
shower. Unless there is a non-return valve on the cold this looks a very
dodgy set up because you are connecting mains pressure to tank pressure
through the shower head.

I assume that there is still a hot water tank, otherwise why the header
tank in the loft? That is, the boiler is working as both a combi (directly
heating mains hot) and a system boiler (heating some kind of hot water
store).

Two alternative solutions; install a pump to take hot water from the tank
and cold water from the loft, or plumb in mains cold to the shower.

In either case the shower should be a high pressure model for mains
pressure as opposed to a low pressure model for gravity fed.

It does sound like a plumbing bodge from what you report.

Cheers


Dave R


--
AMD FX-6300 in GA-990X-Gaming SLI-CF running Windows 7 Pro x64

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

In article ,
AnthonyL wrote:
Since 1992 my friend has had an impossible to control shower which
drives his family (daughter especially) and visitors mad.

It is difficult to believe that given the installation no improvements
were suggested when the Greenstar 28i Junior was installed 7 years
ago.

The shower is on the first floor. The tap is one of those old
fashioned two-into-one with a plunger to change the destination from
down into the bath to up to the shower head.

The hot water is fed at mains pressure, the cold is from a header tank
in the attic directly above, which by my calculations means that cold
water will never make it to the shower head.

On my visit last week I suggested that we simply turn the hot water
temperature down - but no, unlike my (older) boiler there is no
separate control, despite no mention of this in the (on-line) manual.

The guy who posted this:
http://forums.moneysavingexpert.com/....php?t=3584437

seems to have the exact same issue.

My immediate thought is to take a feed from the inlet of the header
tank and connect to the bath's cold water, giving it mains pressure.

Any thoughts?

As a matter of interest, how does the flow of hot and cold compare into
the bath?

Low pressure water from a header tank requires special fittings to have a
chance of working reasonably well, but most fittings on the market are
made abroad, and designed for high pressure. And even then expect
reasonably matched pressure from hot and cold.

One way round would be to fit a pump on the cold water side.

--
*Income tax service - We‘ve got what it takes to take what you've got.

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

On 10/03/2017 11:56, AnthonyL wrote:
Since 1992 my friend has had an impossible to control shower which
drives his family (daughter especially) and visitors mad.

It is difficult to believe that given the installation no improvements
were suggested when the Greenstar 28i Junior was installed 7 years
ago.

The shower is on the first floor. The tap is one of those old
fashioned two-into-one with a plunger to change the destination from
down into the bath to up to the shower head.

The hot water is fed at mains pressure, the cold is from a header tank
in the attic directly above, which by my calculations means that cold
water will never make it to the shower head.

On my visit last week I suggested that we simply turn the hot water
temperature down - but no, unlike my (older) boiler there is no
separate control, despite no mention of this in the (on-line) manual.

The guy who posted this:
http://forums.moneysavingexpert.com/....php?t=3584437

seems to have the exact same issue.

My immediate thought is to take a feed from the inlet of the header
tank and connect to the bath's cold water, giving it mains pressure.

Any thoughts?



Buy a new pressure balancing mixer?
Fit a PRV on the cold side?
Fit a pump and PRV?
Go pressurised hot water.

PRV is cheapest if they get enough flow from the hot.

On Fri, 10 Mar 2017 14:09:34 +0000, dennis@home
wrote:

On 10/03/2017 11:56, AnthonyL wrote:
Since 1992 my friend has had an impossible to control shower which
drives his family (daughter especially) and visitors mad.

It is difficult to believe that given the installation no improvements
were suggested when the Greenstar 28i Junior was installed 7 years
ago.

The shower is on the first floor. The tap is one of those old
fashioned two-into-one with a plunger to change the destination from
down into the bath to up to the shower head.

The hot water is fed at mains pressure, the cold is from a header tank
in the attic directly above, which by my calculations means that cold
water will never make it to the shower head.

On my visit last week I suggested that we simply turn the hot water
temperature down - but no, unlike my (older) boiler there is no
separate control, despite no mention of this in the (on-line) manual.

The guy who posted this:
http://forums.moneysavingexpert.com/....php?t=3584437

seems to have the exact same issue.

My immediate thought is to take a feed from the inlet of the header
tank and connect to the bath's cold water, giving it mains pressure.

Any thoughts?



Buy a new pressure balancing mixer?
Fit a PRV on the cold side?
Fit a pump and PRV?
Go pressurised hot water.

PRV is cheapest if they get enough flow from the hot.

He said the hot water is pressurised so I assume it's from a
combination boiler.
It's the cold that's still via a header tank, so isn't the solution to
connect the shower cold feed to the rising main, along with everything
else, and decommission the tank and cash in the old redundant cylinder
that's presumably still there?
--

Graham.
%Profound_observation%

On Fri, 10 Mar 2017 13:09:17 +0000 (GMT), "Dave Plowman (News)"
wrote:

In article ,
AnthonyL wrote:
Since 1992 my friend has had an impossible to control shower which
drives his family (daughter especially) and visitors mad.

It is difficult to believe that given the installation no improvements
were suggested when the Greenstar 28i Junior was installed 7 years
ago.

The shower is on the first floor. The tap is one of those old
fashioned two-into-one with a plunger to change the destination from
down into the bath to up to the shower head.

The hot water is fed at mains pressure, the cold is from a header tank
in the attic directly above, which by my calculations means that cold
water will never make it to the shower head.

On my visit last week I suggested that we simply turn the hot water
temperature down - but no, unlike my (older) boiler there is no
separate control, despite no mention of this in the (on-line) manual.

The guy who posted this:
http://forums.moneysavingexpert.com/....php?t=3584437

seems to have the exact same issue.

My immediate thought is to take a feed from the inlet of the header
tank and connect to the bath's cold water, giving it mains pressure.

Any thoughts?

As a matter of interest, how does the flow of hot and cold compare into
the bath?

I'm not there now but I assume that the bath tap is one from the days
when there was a hot water tank in the loft so the hot and cold would
have been gravity fed.


Low pressure water from a header tank requires special fittings to have a
chance of working reasonably well, but most fittings on the market are
made abroad, and designed for high pressure. And even then expect
reasonably matched pressure from hot and cold.


The tap is old and I don't think there is anything within the tap to
cater for anything other than a flow of gravity fed so unless a PVR is
fitted to the hot water side which is mains pressure, or the cold is
upped to mains pressure as per my suggestion there will be an
imbalance.

One way round would be to fit a pump on the cold water side.


What is wrong with connecting the mains pressure inlet at the tank to
the bath cold, rather than fit a pump?


--
AnthonyL

On 10 Mar 2017 12:46:02 GMT, David wrote:

On Fri, 10 Mar 2017 11:56:14 +0000, AnthonyL wrote:

Since 1992 my friend has had an impossible to control shower which
drives his family (daughter especially) and visitors mad.

It is difficult to believe that given the installation no improvements
were suggested when the Greenstar 28i Junior was installed 7 years ago.

The shower is on the first floor. The tap is one of those old fashioned
two-into-one with a plunger to change the destination from down into the
bath to up to the shower head.

The hot water is fed at mains pressure, the cold is from a header tank
in the attic directly above, which by my calculations means that cold
water will never make it to the shower head.

On my visit last week I suggested that we simply turn the hot water
temperature down - but no, unlike my (older) boiler there is no separate
control, despite no mention of this in the (on-line) manual.

The guy who posted this:
http://forums.moneysavingexpert.com/....php?t=3584437

seems to have the exact same issue.

My immediate thought is to take a feed from the inlet of the header tank
and connect to the bath's cold water, giving it mains pressure.

Any thoughts?

As far as I am aware you should never mix tank and mains pressure at a
shower. Unless there is a non-return valve on the cold this looks a very
dodgy set up because you are connecting mains pressure to tank pressure
through the shower head.

I assume that there is still a hot water tank, otherwise why the header
tank in the loft? That is, the boiler is working as both a combi (directly
heating mains hot) and a system boiler (heating some kind of hot water
store).


No idea even if there is a hot water tank in the attic. The boiler
provides mains pressure hot water. Cold water is from the tank in the
attic.

Two alternative solutions; install a pump to take hot water from the tank
and cold water from the loft, or plumb in mains cold to the shower.


The latter is what I was proposing by connecting the inlet of the
water tank which is mains to the tap cold, bypassing the cold water
tank.

In either case the shower should be a high pressure model for mains
pressure as opposed to a low pressure model for gravity fed.


He has something like

https://www.diynot.com/diy/threads/b...orking.307877/

but a genuine old version with a knob to lift up to divert the water
into the shower. The knob only stays up if there is pressure so the
cold water alone doesn't hold it.

It does sound like a plumbing bodge from what you report.


Well whoever installed the combi-boiler 11yrs ago surely could have
sorted it without much more effort, but if my friend didn't ask then
maybe they just took the old out and put the new in?

--
AnthonyL

In article ,
Graham. wrote:
He said the hot water is pressurised so I assume it's from a
combination boiler.
It's the cold that's still via a header tank, so isn't the solution to
connect the shower cold feed to the rising main, along with everything
else, and decommission the tank and cash in the old redundant cylinder
that's presumably still there?

If you have sufficient flow and pressure, possibly. But when turning on
another tap anywhere in the house effects the shower, not so sure.

--
*Many people quit looking for work when they find a job *

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

On 10/03/2017 15:58, Graham. wrote:
On Fri, 10 Mar 2017 14:09:34 +0000, dennis@home
wrote:

On 10/03/2017 11:56, AnthonyL wrote:
Since 1992 my friend has had an impossible to control shower which
drives his family (daughter especially) and visitors mad.

It is difficult to believe that given the installation no improvements
were suggested when the Greenstar 28i Junior was installed 7 years
ago.

The shower is on the first floor. The tap is one of those old
fashioned two-into-one with a plunger to change the destination from
down into the bath to up to the shower head.

The hot water is fed at mains pressure, the cold is from a header tank
in the attic directly above, which by my calculations means that cold
water will never make it to the shower head.

On my visit last week I suggested that we simply turn the hot water
temperature down - but no, unlike my (older) boiler there is no
separate control, despite no mention of this in the (on-line) manual.

The guy who posted this:
http://forums.moneysavingexpert.com/....php?t=3584437

seems to have the exact same issue.

My immediate thought is to take a feed from the inlet of the header
tank and connect to the bath's cold water, giving it mains pressure.

Any thoughts?



Buy a new pressure balancing mixer?
Fit a PRV on the cold side?
Fit a pump and PRV?
Go pressurised hot water.

PRV is cheapest if they get enough flow from the hot.

He said the hot water is pressurised so I assume it's from a
combination boiler.
It's the cold that's still via a header tank, so isn't the solution to
connect the shower cold feed to the rising main, along with everything
else, and decommission the tank and cash in the old redundant cylinder
that's presumably still there?


That's what happens when you don't read the question.
So put the PVR on the hot side if there is enough flow from the cold or
as you say connect the cold to the mains which should be easy to do next
to the tank.

dennis@home Wrote in message:
On 10/03/2017 15:58, Graham. wrote:
On Fri, 10 Mar 2017 14:09:34 +0000, dennis@home
wrote:

On 10/03/2017 11:56, AnthonyL wrote:
Since 1992 my friend has had an impossible to control shower which
drives his family (daughter especially) and visitors mad.

It is difficult to believe that given the installation no improvements
were suggested when the Greenstar 28i Junior was installed 7 years
ago.

The shower is on the first floor. The tap is one of those old
fashioned two-into-one with a plunger to change the destination from
down into the bath to up to the shower head.

The hot water is fed at mains pressure, the cold is from a header tank
in the attic directly above, which by my calculations means that cold
water will never make it to the shower head.

On my visit last week I suggested that we simply turn the hot water
temperature down - but no, unlike my (older) boiler there is no
separate control, despite no mention of this in the (on-line) manual.

The guy who posted this:
http://forums.moneysavingexpert.com/....php?t=3584437

seems to have the exact same issue.

My immediate thought is to take a feed from the inlet of the header
tank and connect to the bath's cold water, giving it mains pressure.

Any thoughts?



Buy a new pressure balancing mixer?
Fit a PRV on the cold side?
Fit a pump and PRV?
Go pressurised hot water.

PRV is cheapest if they get enough flow from the hot.

He said the hot water is pressurised so I assume it's from a
combination boiler.
It's the cold that's still via a header tank, so isn't the solution to
connect the shower cold feed to the rising main, along with everything
else, and decommission the tank and cash in the old redundant cylinder
that's presumably still there?


That's what happens when you don't read the question.
So put the PVR on the hot side if there is enough flow from the cold or
as you say connect the cold to the mains which should be easy to do next
to the tank.



Why would a Personal Video Recorder be any use in this situation?
--
Jim K

"Dave Plowman (News)" Wrote in message:
In article ,
Graham. wrote:
He said the hot water is pressurised so I assume it's from a
combination boiler.
It's the cold that's still via a header tank, so isn't the solution to
connect the shower cold feed to the rising main, along with everything
else, and decommission the tank and cash in the old redundant cylinder
that's presumably still there?

If you have sufficient flow and pressure, possibly. But when turning on
another tap anywhere in the house effects the shower, not so sure.


pedant on affectspedant off

--
Jim K

On Fri, 10 Mar 2017 16:26:02 +0000, AnthonyL wrote:

On 10 Mar 2017 12:46:02 GMT, David wrote:

On Fri, 10 Mar 2017 11:56:14 +0000, AnthonyL wrote:

Since 1992 my friend has had an impossible to control shower which
drives his family (daughter especially) and visitors mad.

It is difficult to believe that given the installation no improvements
were suggested when the Greenstar 28i Junior was installed 7 years
ago.

The shower is on the first floor. The tap is one of those old
fashioned two-into-one with a plunger to change the destination from
down into the bath to up to the shower head.

The hot water is fed at mains pressure, the cold is from a header tank
in the attic directly above, which by my calculations means that cold
water will never make it to the shower head.

On my visit last week I suggested that we simply turn the hot water
temperature down - but no, unlike my (older) boiler there is no
separate control, despite no mention of this in the (on-line) manual.

The guy who posted this:
http://forums.moneysavingexpert.com/....php?t=3584437

seems to have the exact same issue.

My immediate thought is to take a feed from the inlet of the header
tank and connect to the bath's cold water, giving it mains pressure.

Any thoughts?

As far as I am aware you should never mix tank and mains pressure at a
shower. Unless there is a non-return valve on the cold this looks a very
dodgy set up because you are connecting mains pressure to tank pressure
through the shower head.

I assume that there is still a hot water tank, otherwise why the header
tank in the loft? That is, the boiler is working as both a combi
(directly heating mains hot) and a system boiler (heating some kind of
hot water store).
snip

It is unlikely that there would have been a hot water tank in the loft.

Usually a system is all mains pressure (as with a combi boiler) or
(almost) all gravity.

With a gravity system you have a cold water header tank in the loft and
then a hot water copper cylinder in an airing cupboard, often close to or
in the bathroom. Hot water is pre heated and then when the hot tap is
turned on cold water from the loft flows into the bottom of the hot water
cylinder and forces hot out of the top and through the hot tap.

One important thing is to have a mains cold water tap for drinking water
as cold water in the loft tank can sit there for a while and can also get
contaminated by vermin.

What you describe is not a normal system and sounds suspiciously like a
cowboy installation. Usually if a hot water cylinder is removed and a combi
boiler fitted then all the cold water is converted to mains pressure and
the header tank is removed.

The only usual reason for a header tank in the loft is to provide a head
of water for the hot water tank. In that case the cold feed to a mixer tap
should also be from the header tank.

Your original suggestion that mains pressure should be connected to the
cold side of the shower was sensible; however we are asking further
questions to try and establish if this is an unusual but generally logical
set up.

For example there may still be a hot water cylinder which supplies all the
hot taps apart from the shower, and the combi boiler may have a circuit on
the central heating side which heats both the radiators and the hot water
cylinder.

The second point being made is that if the shower mixer is a hang over
from a low pressure gravity feed system then it may be unsuitable for a
mains pressure system even when both hot and cold feeds are at mains
pressure.

If you have a mains pressure combi boiler there is a limit to the amount
of hot water it can supply by instantaneously heating the incoming cold
water and the shower has to be designed to produce a good high pressure
spray at this flow rate. It has to work at a low flow rate and a high
pressure.

Low pressure tank fed showers tend to pass a lot more water through at a
much lower pressure to provide a satisfying shower. If you use a low
pressure shower mixer with a mains pressure supply you may never get a
decent shower.

From online specifications the boiler should provide a hot water flow of
between 10 and 13 litres per minute (assuming enough pressure and flow
from the incoming main). If the shower is not designed to operate at that
flow rate then you are wasting your time. Connect the cold mains to the
input to the shower mixer to match the hot mains, but be prepared to also
fit a new mixer designed to work with a combi boiler.

I do have a (possibly unworthy) suspicion that if this shower has been
endured for so long there may be a reason why it hasn't been fixed.
Perhaps a reluctance to spend money?

TL;DR - connect mains cold to the bath, and fit a new mixer.

Cheers


Dave R


--
AMD FX-6300 in GA-990X-Gaming SLI-CF running Windows 7 Pro x64

---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus

On Fri, 10 Mar 2017 16:58:23 +0000 (GMT), "Dave Plowman (News)"
wrote:

In article ,
Graham. wrote:
He said the hot water is pressurised so I assume it's from a
combination boiler.
It's the cold that's still via a header tank, so isn't the solution to
connect the shower cold feed to the rising main, along with everything
else, and decommission the tank and cash in the old redundant cylinder
that's presumably still there?

If you have sufficient flow and pressure, possibly. But when turning on
another tap anywhere in the house effects the shower, not so sure.

That's true, it's not perfect, but it's how the majority of
thermostatic showers in the UK are plumbed, and it must be miles
better than HP hot + LP cold.
--

Graham.
%Profound_observation%

On Fri, 10 Mar 2017 17:51:59 +0000, dennis@home
wrote:

On 10/03/2017 15:58, Graham. wrote:
On Fri, 10 Mar 2017 14:09:34 +0000, dennis@home
wrote:

On 10/03/2017 11:56, AnthonyL wrote:
Since 1992 my friend has had an impossible to control shower which
drives his family (daughter especially) and visitors mad.

It is difficult to believe that given the installation no improvements
were suggested when the Greenstar 28i Junior was installed 7 years
ago.

The shower is on the first floor. The tap is one of those old
fashioned two-into-one with a plunger to change the destination from
down into the bath to up to the shower head.

The hot water is fed at mains pressure, the cold is from a header tank
in the attic directly above, which by my calculations means that cold
water will never make it to the shower head.

On my visit last week I suggested that we simply turn the hot water
temperature down - but no, unlike my (older) boiler there is no
separate control, despite no mention of this in the (on-line) manual.

The guy who posted this:
http://forums.moneysavingexpert.com/....php?t=3584437

seems to have the exact same issue.

My immediate thought is to take a feed from the inlet of the header
tank and connect to the bath's cold water, giving it mains pressure.

Any thoughts?



Buy a new pressure balancing mixer?
Fit a PRV on the cold side?
Fit a pump and PRV?
Go pressurised hot water.

PRV is cheapest if they get enough flow from the hot.

He said the hot water is pressurised so I assume it's from a
combination boiler.
It's the cold that's still via a header tank, so isn't the solution to
connect the shower cold feed to the rising main, along with everything
else, and decommission the tank and cash in the old redundant cylinder
that's presumably still there?


That's what happens when you don't read the question.
So put the PVR on the hot side if there is enough flow from the cold or
as you say connect the cold to the mains which should be easy to do next
to the tank.

I wouldn't want a water pipe making a dog-leg detour through my cold
loft space when there is no longer any reason to do so.


--

Graham.
%Profound_observation%

On 10/03/17 20:29, David wrote:
On Fri, 10 Mar 2017 16:26:02 +0000, AnthonyL wrote:

On 10 Mar 2017 12:46:02 GMT, David wrote:

On Fri, 10 Mar 2017 11:56:14 +0000, AnthonyL wrote:

Since 1992 my friend has had an impossible to control shower which
drives his family (daughter especially) and visitors mad.

It is difficult to believe that given the installation no improvements
were suggested when the Greenstar 28i Junior was installed 7 years
ago.

The shower is on the first floor. The tap is one of those old
fashioned two-into-one with a plunger to change the destination from
down into the bath to up to the shower head.

The hot water is fed at mains pressure, the cold is from a header tank
in the attic directly above, which by my calculations means that cold
water will never make it to the shower head.

On my visit last week I suggested that we simply turn the hot water
temperature down - but no, unlike my (older) boiler there is no
separate control, despite no mention of this in the (on-line) manual.

The guy who posted this:
http://forums.moneysavingexpert.com/....php?t=3584437

seems to have the exact same issue.

My immediate thought is to take a feed from the inlet of the header
tank and connect to the bath's cold water, giving it mains pressure.

Any thoughts?

As far as I am aware you should never mix tank and mains pressure at a
shower. Unless there is a non-return valve on the cold this looks a very
dodgy set up because you are connecting mains pressure to tank pressure
through the shower head.

I assume that there is still a hot water tank, otherwise why the header
tank in the loft? That is, the boiler is working as both a combi
(directly heating mains hot) and a system boiler (heating some kind of
hot water store).
snip

It is unlikely that there would have been a hot water tank in the loft.

Usually a system is all mains pressure (as with a combi boiler) or
(almost) all gravity.

With a gravity system you have a cold water header tank in the loft and
then a hot water copper cylinder in an airing cupboard, often close to or
in the bathroom. Hot water is pre heated and then when the hot tap is
turned on cold water from the loft flows into the bottom of the hot water
cylinder and forces hot out of the top and through the hot tap.

One important thing is to have a mains cold water tap for drinking water
as cold water in the loft tank can sit there for a while and can also get
contaminated by vermin.

What you describe is not a normal system and sounds suspiciously like a
cowboy installation. Usually if a hot water cylinder is removed and a combi
boiler fitted then all the cold water is converted to mains pressure and
the header tank is removed.

The only usual reason for a header tank in the loft is to provide a head
of water for the hot water tank. In that case the cold feed to a mixer tap
should also be from the header tank.

Your original suggestion that mains pressure should be connected to the
cold side of the shower was sensible; however we are asking further
questions to try and establish if this is an unusual but generally logical
set up.

For example there may still be a hot water cylinder which supplies all the
hot taps apart from the shower, and the combi boiler may have a circuit on
the central heating side which heats both the radiators and the hot water
cylinder.

The second point being made is that if the shower mixer is a hang over
from a low pressure gravity feed system then it may be unsuitable for a
mains pressure system even when both hot and cold feeds are at mains
pressure.

If you have a mains pressure combi boiler there is a limit to the amount
of hot water it can supply by instantaneously heating the incoming cold
water and the shower has to be designed to produce a good high pressure
spray at this flow rate. It has to work at a low flow rate and a high
pressure.

Low pressure tank fed showers tend to pass a lot more water through at a
much lower pressure to provide a satisfying shower. If you use a low
pressure shower mixer with a mains pressure supply you may never get a
decent shower.

From online specifications the boiler should provide a hot water flow of
between 10 and 13 litres per minute (assuming enough pressure and flow
from the incoming main). If the shower is not designed to operate at that
flow rate then you are wasting your time. Connect the cold mains to the
input to the shower mixer to match the hot mains, but be prepared to also
fit a new mixer designed to work with a combi boiler.

I do have a (possibly unworthy) suspicion that if this shower has been
endured for so long there may be a reason why it hasn't been fixed.
Perhaps a reluctance to spend money?

TL;DR - connect mains cold to the bath, and fit a new mixer.

Cheers


Dave R

Cowboy installation? Maybe.

It took me quite a while to get my head round the water supply in our
bungalow. It has a standard (non-combi) gas boiler, and the usual tanks
in the loft - cold water and expansion. There was also a double-sized
hot water cylinder.

There are four showers! One is an instant electric one in one bedroom.
The master bedroom has an en-suite, and the main bathroom has a shower
cubicle, and shower attachment on the bath taps (of the sort shown in
the previous post link). The en-suite and bathroom cubicle showers have
pumps (hence the need for a double-sized HW cylinder). The HW and CW
supply to the shower pumps is taken from the CW tank and HW cylinder. So
far so good. It is when I started looking at the CW supply to the rest
of the bathroom and en-suite fittings that it became interesting.

I found the bath shower attachment very sensitive to the CW tap setting.
With the HW tap fully on, slightly opening the CW tap led to a cold
shower only. And if left for a few minutes, the HW didn't immediately
reappear when the CW was turned off. It was obvious that CW was being
forced back into the HW system. It then became clear why I had had to
turn off the isolator valve almost completely for the CW supply to the
bath and en-suite basins. It was very easy to open the quarter-turn taps
fully and get drenched with splashback from the basin!

Effectively, only the showers were fed (via the pumps) from the CW tank.
All other CW supply, to the bath, basins, and cisterns, was at mains
pressure. When I mentioned this to our plumber one time, he said that it
was unusual, but he had seen it occasional.

--

Jeff

On 11/03/2017 09:15, Jeff Layman wrote:

Effectively, only the showers were fed (via the pumps) from the CW tank.
All other CW supply, to the bath, basins, and cisterns, was at mains
pressure. When I mentioned this to our plumber one time, he said that it
was unusual, but he had seen it occasional.


Its the normal way to do water in the Midlands and in many other parts
of the UK where there is good mains pressure.

Its also the best way as it is safer than having tanks of stagnant water
available from taps.

It does mean you need to run the cold for mixers from the header tank if
you have a conventional (old?) system.

On 10 Mar 2017 20:29:41 GMT, David wrote:
snip


It is unlikely that there would have been a hot water tank in the loft.

There was in my existing (1968) bungalow but not in my previous and
older 2 storey house where the header tank sat above the hot water
cylinder in the bathroom.


Usually a system is all mains pressure (as with a combi boiler) or
(almost) all gravity.

I don't have enough experience to say "usually".


With a gravity system you have a cold water header tank in the loft and
then a hot water copper cylinder in an airing cupboard, often close to or
in the bathroom. Hot water is pre heated and then when the hot tap is
turned on cold water from the loft flows into the bottom of the hot water
cylinder and forces hot out of the top and through the hot tap.


Or variations of the above it would seem.

One important thing is to have a mains cold water tap for drinking water
as cold water in the loft tank can sit there for a while and can also get
contaminated by vermin.

Agreed, I'm not convinced my friend has this, but he's still alive
after 35yrs of living there.


What you describe is not a normal system and sounds suspiciously like a
cowboy installation. Usually if a hot water cylinder is removed and a combi
boiler fitted then all the cold water is converted to mains pressure and
the header tank is removed.


An older (presumably non-combi and less efficient) boiler had been
fitted and replaced 7 yrs ago.


The only usual reason for a header tank in the loft is to provide a head
of water for the hot water tank. In that case the cold feed to a mixer tap
should also be from the header tank.

Well yes that is exacerbating the problem. I don't think any cold
water is actually reaching the shower head, it is just going to get
pushed back up to that height by the mains pressure hot.


Your original suggestion that mains pressure should be connected to the
cold side of the shower was sensible; however we are asking further
questions to try and establish if this is an unusual but generally logical
set up.

Fair enough - I can't pop up now to check.


For example there may still be a hot water cylinder which supplies all the
hot taps apart from the shower, and the combi boiler may have a circuit on
the central heating side which heats both the radiators and the hot water
cylinder.

The second point being made is that if the shower mixer is a hang over
from a low pressure gravity feed system then it may be unsuitable for a
mains pressure system even when both hot and cold feeds are at mains
pressure.


Almost certainly. The hot water tap in the adjacent sink drips,
possibly for that reason.

If you have a mains pressure combi boiler there is a limit to the amount
of hot water it can supply by instantaneously heating the incoming cold
water and the shower has to be designed to produce a good high pressure
spray at this flow rate. It has to work at a low flow rate and a high
pressure.


There is plenty of hot water gushing out and it's far too hot for a
shower.


Low pressure tank fed showers tend to pass a lot more water through at a
much lower pressure to provide a satisfying shower. If you use a low
pressure shower mixer with a mains pressure supply you may never get a
decent shower.


From online specifications the boiler should provide a hot water flow of
between 10 and 13 litres per minute (assuming enough pressure and flow
from the incoming main). If the shower is not designed to operate at that
flow rate then you are wasting your time. Connect the cold mains to the
input to the shower mixer to match the hot mains, but be prepared to also
fit a new mixer designed to work with a combi boiler.


I had hoped that we could simply turn the hot water temperature down
(we have a separate control on our boiler) but despite showing a
separate control in the on-line manual it would seem that the hot
water temp is fixed at 55deg.

I do have a (possibly unworthy) suspicion that if this shower has been
endured for so long there may be a reason why it hasn't been fixed.
Perhaps a reluctance to spend money?

Combination of ignorance and lack of good advice I suspect.


TL;DR - connect mains cold to the bath, and fit a new mixer.


Certainly one option, or PVR as elsewhere suggested. I've recommended
he try and find a decent plumber but we are talking Walthamstow and
I'm used to East Midland prices.

--
AnthonyL

In article ,
Jeff Layman wrote:
Effectively, only the showers were fed (via the pumps) from the CW tank.
All other CW supply, to the bath, basins, and cisterns, was at mains
pressure. When I mentioned this to our plumber one time, he said that it
was unusual, but he had seen it occasional.

There are all sorts of variations by area. In London, it was common to
have everything from the header tank except the kitchen cold water. I've
even seen some older houses with tank cold water to the kitchen too - so
three taps. Stored hot water produced by some form of back boiler.

But that dated back to houses built with a single bathroom with just a
bath.

I've kept things that way here. Despite having an additional bathroom with
a shower rather than bath.

Only modification is to have mains cold water to bathroom basin taps for
teeth cleaning, etc.

--
*Not all men are annoying. Some are dead.

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

In article ,
Dave Plowman (News) wrote:
In article ,
Jeff Layman wrote:
Effectively, only the showers were fed (via the pumps) from the CW tank.
All other CW supply, to the bath, basins, and cisterns, was at mains
pressure. When I mentioned this to our plumber one time, he said that it
was unusual, but he had seen it occasional.

There are all sorts of variations by area. In London, it was common to
have everything from the header tank except the kitchen cold water. I've
even seen some older houses with tank cold water to the kitchen too - so
three taps. Stored hot water produced by some form of back boiler.

But that dated back to houses built with a single bathroom with just a
bath.

I think it used to be part of then Scottish Water Regs.


I've kept things that way here. Despite having an additional bathroom with
a shower rather than bath.

Only modification is to have mains cold water to bathroom basin taps for
teeth cleaning, etc.

--
from KT24 in Surrey, England

On 10/03/2017 11:56, AnthonyL wrote:

My immediate thought is to take a feed from the inlet of the header
tank and connect to the bath's cold water, giving it mains pressure.

That may help, but alone but may not solve all the problems.

You really need mains (or similar) pressure feed on both hot and cold,
and then either a thermostatic shower or at least a pressure balanced one.

If there is a separate identifiable cold feed to the bath, then by all
means connect it to the cold main.

As to solving other problems - much depends on what the actual issues
are - there are a number of ways that combi fed showers can not perform
to expectations.


--
Cheers,

John.

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

From my own experience.

1) Plunger on shower connector not staying up:

Temporary cure - use a plastic peg with a bit carved out to fit the
spindle to keep it up.

Permanent cure - replace the tap / shower unit with one that has a plunger
that you press down for the shower - Wickes do them.

2) Cold water: even a tank just a few feet above the shower head should
give enough water flow unless there is an obstruction.

Check the cold water feed pipe between the bath cold tap and the tank for
an isolation or gate valve and make sure that it is fully open.

Look in the tank where the cold feed pipe emerges - is anything stuck in
it like loft insulation reducing the feed? I've had that happen and had to
blow it out by sending mains pressure water up the pipe.

3) Hot water:

Is there an isolation or gate valve on the hot water pipe to the bath? If
so partially close it to reduce the flow to be similar to that of the cold
water or fit one.

Even without that, provided the taps are as shown in the link you gave ie
not a ceramic disk but the older type with a washer that screws down
requiring several turns of the tap to turn it off, provided the washer
isn't badly worn, you should be able to turn it on slightly to give a slow
flow of hot water to match that of the cold tap fully open. Then use the
peg to keep the shower working. This will allow a slow shower of the
correct temperature (provided no one else uses a tap or tioilet fed from
the same cold water pipe).

4) Increasing the water flow now the temperature mix is OK:

If the shower hose is an old coiled metal type then the narrow plastic
tube inside is likely to be distorted and reducing the flow - replace it
with a new wider reinforced plastic one.

Descale the shower head or replace it.

If they still wqant a faster flow and don't want the disruption of
replumbing then do what I did fit a Triton T40i booster shower pump. This
is just a pump (not a heater) which only takes 90W maximum so is easy to
fit - I drilled through to the next room and either wired in a new
isolation socket or temporarily just plugged into a socket. The shower
connector from the taps is connected by a hose to the inlet and then the
shower connected to the outlet. With it turned off and the water running
into the bath, turn the cold tap on full, adjust the temperature by
slighty turning on the hot tap, pull up the plunger and fix with the peg,
once some water is coming from the shower head turn on the pump. You will
then get a good flow of water at the right temperature. NB To avoid damage
the pump must be turned off before turning off the taps. - that worked
until we had time for the disruption of plumbing work.

Good luck

Alan

--


Using an ARMX6