[Alan \(BigAl\)]

Am I right in saying that with a combination boiler with no header tank,
with direct connection to the mains water, that is is inappropriate to use a
booster pump?

I am planning to redo the bathroom, to include a separate shower unit. I was
planning to use a thermostatic controlled shower unit to blend hot and cold
feeds.

Presently we have a shower over the bath, with a combined tap/shower without
any temperature regulation.
This is very hard to adjust and both the hot and cold flows seem to be quite
restricted. However, the old tap/shower unit may well have got a bit of
scale or gunge, but I was expecting more vigorous flow, and suspected that
the low pressure might be detrimental with a new shower too.

I just did a pressure test, and have 32 psi dead ended pressure.
This was on the ground floor, so 3 metres higher (bathroom upstairs) it will
be ~5 psi lower.

That seems a bit lower than I expected, but I have no real data to compare
it with.

Checking the installation instructions from a shower plucked at random from
'tinterweb, it seems that it would be ok with pressures of 1 bar, or even
lower if the flow restrictors are removed.

Am I worrying needlessly? Am I missing something? Does anyone have any
advice for me please?



Cheers Alan

[dennis@home]

"Alan (BigAl)" wrote in message
...


Am I worrying needlessly? Am I missing something? Does anyone have any
advice for me please?

You usually have plenty of pressure with a combi.
That doesn't mean you have plenty of flow.
The combi can only heat a limited number of litres per minute.
Typically you can get about 8-15 litres per minute.
This may be enough if you have a suitable shower head.
Don't expect it to be enough if you imagine having a 30cm square soaker
hanging from the ceiling.
Fit a thermostatic mixer or you will find the temp changes when someone
turns a tap on, etc.

[DavidM]

On Tue, 12 Jul 2011 14:10:13 +0100, "Alan \(BigAl\)"
wrote:

Am I right in saying that with a combination boiler with no header tank,
with direct connection to the mains water, that is is inappropriate to use a
booster pump?

I am planning to redo the bathroom, to include a separate shower unit. I was
planning to use a thermostatic controlled shower unit to blend hot and cold
feeds.

Presently we have a shower over the bath, with a combined tap/shower without
any temperature regulation.
This is very hard to adjust and both the hot and cold flows seem to be quite
restricted. However, the old tap/shower unit may well have got a bit of
scale or gunge, but I was expecting more vigorous flow, and suspected that
the low pressure might be detrimental with a new shower too.

I just did a pressure test, and have 32 psi dead ended pressure.
This was on the ground floor, so 3 metres higher (bathroom upstairs) it will
be ~5 psi lower.

That seems a bit lower than I expected, but I have no real data to compare
it with.

Checking the installation instructions from a shower plucked at random from
'tinterweb, it seems that it would be ok with pressures of 1 bar, or even
lower if the flow restrictors are removed.

Am I worrying needlessly? Am I missing something? Does anyone have any
advice for me please?



Cheers Alan

Before installing a shower in my son's bathroom a couple of years ago
(albeit one over a bath) I lashed up a connection using garden hose
between the hot water feed from the combi and his new shower head,
temporarily fixed at roughly the finished height with bucket
underneath, just to check the flow/pressure. It seemed ok.

Final installation had hot and cold feed into a thermostatic mixer,
thence to normal shower head on flexible hose. Still working ok and no
problems with other taps being turned on/off.

As said above, don't expect a waterfall shower through a combi!

[TMC[_2_]]

"Alan (BigAl)" wrote in message
...
Am I right in saying that with a combination boiler with no header tank,
with direct connection to the mains water, that is is inappropriate to use
a booster pump?

I am planning to redo the bathroom, to include a separate shower unit. I
was planning to use a thermostatic controlled shower unit to blend hot and
cold feeds.

Presently we have a shower over the bath, with a combined tap/shower
without any temperature regulation.
This is very hard to adjust and both the hot and cold flows seem to be
quite restricted. However, the old tap/shower unit may well have got a bit
of scale or gunge, but I was expecting more vigorous flow, and suspected
that the low pressure might be detrimental with a new shower too.

I just did a pressure test, and have 32 psi dead ended pressure.
This was on the ground floor, so 3 metres higher (bathroom upstairs) it
will be ~5 psi lower.

That seems a bit lower than I expected, but I have no real data to compare
it with.

Checking the installation instructions from a shower plucked at random
from 'tinterweb, it seems that it would be ok with pressures of 1 bar, or
even lower if the flow restrictors are removed.

Am I worrying needlessly? Am I missing something? Does anyone have any
advice for me please?



Cheers Alan
I am sure there will be an expert along soon

but in the meantime

for a combi boiler system use a pressure balanced mixer

traditional showers have a temperature balanced mixer which needs the
incoming supply of both hot and cold to be the same pressure the cold feed
would come from the output of the header tank for the hot water system not
from the incoming mains

A pressure balanced shower assumes a constant hot water temperature which
one normally gets from a combi boiler and balances the differential in
pressure to get the required temperature

I have had a mira one fitted for 18 years without problem other than
replacing the shower head once and hose twice

I do not see how a booster pump can work with fixed volume output from the
boiler

Regards

Regards

[fred]

In article , TMC
writes

I do not see how a booster pump can work with fixed volume output from the
boiler

Yep, that's right, flow will be limited by the heat output of the
boiler.

Worth noting too that you're not allowed to pump from the mains (either
on the cold feed or via the combi), only from a tank fed system. It's to
do with the risk of causing negative pressure in the mains and sucking
in impurities or bacteria.
--
fred
FIVE TV's superbright logo - not the DOG's, it's ********

[MuddyMike]

"TMC" wrote in message
...

"Alan (BigAl)" wrote in message
...
Am I right in saying that with a combination boiler with no header tank,
with direct connection to the mains water, that is is inappropriate to
use a booster pump?

I am planning to redo the bathroom, to include a separate shower unit. I
was planning to use a thermostatic controlled shower unit to blend hot
and cold feeds.

Presently we have a shower over the bath, with a combined tap/shower
without any temperature regulation.
This is very hard to adjust and both the hot and cold flows seem to be
quite restricted. However, the old tap/shower unit may well have got a
bit of scale or gunge, but I was expecting more vigorous flow, and
suspected that the low pressure might be detrimental with a new shower
too.

I just did a pressure test, and have 32 psi dead ended pressure.
This was on the ground floor, so 3 metres higher (bathroom upstairs) it
will be ~5 psi lower.

That seems a bit lower than I expected, but I have no real data to
compare it with.

Checking the installation instructions from a shower plucked at random
from 'tinterweb, it seems that it would be ok with pressures of 1 bar, or
even lower if the flow restrictors are removed.

Am I worrying needlessly? Am I missing something? Does anyone have any
advice for me please?



Cheers Alan
I am sure there will be an expert along soon

but in the meantime

for a combi boiler system use a pressure balanced mixer

traditional showers have a temperature balanced mixer which needs the
incoming supply of both hot and cold to be the same pressure the cold feed
would come from the output of the header tank for the hot water system not
from the incoming mains


I am confused, I thought combi boilers did away with the loft tank? Don't
both hot and cold come at mains pressure?

Mike

[TMC[_2_]]

"MuddyMike" wrote in message
om...

"TMC" wrote in message
...

"Alan (BigAl)" wrote in message
...
Am I right in saying that with a combination boiler with no header tank,
with direct connection to the mains water, that is is inappropriate to
use a booster pump?

I am planning to redo the bathroom, to include a separate shower unit. I
was planning to use a thermostatic controlled shower unit to blend hot
and cold feeds.

Presently we have a shower over the bath, with a combined tap/shower
without any temperature regulation.
This is very hard to adjust and both the hot and cold flows seem to be
quite restricted. However, the old tap/shower unit may well have got a
bit of scale or gunge, but I was expecting more vigorous flow, and
suspected that the low pressure might be detrimental with a new shower
too.

I just did a pressure test, and have 32 psi dead ended pressure.
This was on the ground floor, so 3 metres higher (bathroom upstairs) it
will be ~5 psi lower.

That seems a bit lower than I expected, but I have no real data to
compare it with.

Checking the installation instructions from a shower plucked at random
from 'tinterweb, it seems that it would be ok with pressures of 1 bar,
or even lower if the flow restrictors are removed.

Am I worrying needlessly? Am I missing something? Does anyone have any
advice for me please?



Cheers Alan
I am sure there will be an expert along soon

but in the meantime

for a combi boiler system use a pressure balanced mixer

traditional showers have a temperature balanced mixer which needs the
incoming supply of both hot and cold to be the same pressure the cold
feed would come from the output of the header tank for the hot water
system not from the incoming mains


I am confused, I thought combi boilers did away with the loft tank? Don't
both hot and cold come at mains pressure?

Mike
the pressure to the boiler for the hot water is mains pressure in thbut the
output of the boiler is limited to the heating potential of the boiler

[MuddyMike]

"TMC" wrote in message
...

"MuddyMike" wrote in message
om...

"TMC" wrote in message
...

"Alan (BigAl)" wrote in message
...
Am I right in saying that with a combination boiler with no header
tank, with direct connection to the mains water, that is is
inappropriate to use a booster pump?

I am planning to redo the bathroom, to include a separate shower unit.
I was planning to use a thermostatic controlled shower unit to blend
hot and cold feeds.

Presently we have a shower over the bath, with a combined tap/shower
without any temperature regulation.
This is very hard to adjust and both the hot and cold flows seem to be
quite restricted. However, the old tap/shower unit may well have got a
bit of scale or gunge, but I was expecting more vigorous flow, and
suspected that the low pressure might be detrimental with a new shower
too.

I just did a pressure test, and have 32 psi dead ended pressure.
This was on the ground floor, so 3 metres higher (bathroom upstairs) it
will be ~5 psi lower.

That seems a bit lower than I expected, but I have no real data to
compare it with.

Checking the installation instructions from a shower plucked at random
from 'tinterweb, it seems that it would be ok with pressures of 1 bar,
or even lower if the flow restrictors are removed.

Am I worrying needlessly? Am I missing something? Does anyone have any
advice for me please?



Cheers Alan
I am sure there will be an expert along soon

but in the meantime

for a combi boiler system use a pressure balanced mixer

traditional showers have a temperature balanced mixer which needs the
incoming supply of both hot and cold to be the same pressure the cold
feed would come from the output of the header tank for the hot water
system not from the incoming mains


I am confused, I thought combi boilers did away with the loft tank? Don't
both hot and cold come at mains pressure?

Mike
the pressure to the boiler for the hot water is mains pressure in thbut
the output of the boiler is limited to the heating potential of the boiler

The flow may be restricted but surely the pressure is the same?

Mike

[Alan \(BigAl\)]

Thanks all for the input.
I think that I will use one of these : -
http://www.betterbathrooms.com/showe...ide-rail-pack/
or summat similar.

Now - if I mount it into a corner with two solid brick walls, how best to
pipe up to it?
Is it usual to create a false wall and tile it, or cut a channel for the
pipes?

Sorry for the stupid questions, but this is one of the few jobs around the
house that I have not yet tried to do.

[dennis@home]

"Alan (BigAl)" wrote in message
...
Thanks all for the input.
I think that I will use one of these : -
http://www.betterbathrooms.com/showe...ide-rail-pack/
or summat similar.

Now - if I mount it into a corner with two solid brick walls, how best to
pipe up to it?
Is it usual to create a false wall and tile it, or cut a channel for the
pipes?


Its quite common to see stainless steel pipe running down the walls to a
surface mounted valve in those situations.

Sorry for the stupid questions, but this is one of the few jobs around the
house that I have not yet tried to do.

No such thing as a stupid question, only stupid answers.

[Roger Mills[_2_]]

On 12/07/2011 23:22, Alan (BigAl) wrote:
Thanks all for the input.
I think that I will use one of these : -
http://www.betterbathrooms.com/showe...ide-rail-pack/
or summat similar.

Now - if I mount it into a corner with two solid brick walls, how best to
pipe up to it?
Is it usual to create a false wall and tile it, or cut a channel for the
pipes?

Sorry for the stupid questions, but this is one of the few jobs around the
house that I have not yet tried to do.



You'll probably want to tile it, either way. In your situation, I'd cut
a channel in the brickwork and use copper pipes - with compression to FI
elbows at the appropriate place for connecting the shower.
--
Cheers,
Roger
____________
Please reply to Newsgroup. Whilst email address is valid, it is seldom
checked.

[MuddyMike]

"Alan (BigAl)" wrote in message
...
Thanks all for the input.
I think that I will use one of these : -
http://www.betterbathrooms.com/showe...ide-rail-pack/
or summat similar.

Now - if I mount it into a corner with two solid brick walls, how best to
pipe up to it?
Is it usual to create a false wall and tile it, or cut a channel for the
pipes?

Sorry for the stupid questions, but this is one of the few jobs around the
house that I have not yet tried to do.


I found that cutting a plywood template with two holes to keep the pipe ends
in the right place and at the correct distance apart was a great help when I
fitted a similar shower with the pipes embedded into chases in a brick wall.

Mike