Hi

We've had a thermostatic shower fitted - one of those where you turn
one dial to set the heat (notionally marked in deg C) and the other to
set the water flow strength.

But to get an acceptable temperature, the heat setting has to be set
as low as possible, otherwise it would scald. Is there likely to be
something that can be adjusted in the shower mixer so that the heat
markings are more closely approximate to the actual temperature being
output? For the record, I like a really hot shower, so its not just
me not able to handle the heat!

Hot water is supplied from a combi.

Thanks!

Matt

On 25/03/2008 09:01, wrote:

We've had a thermostatic shower fitted
But to get an acceptable temperature, the heat setting has to be set
as low as possible, otherwise it would scald.

Certainly the Mira Excel allows you to offset the temperature range, by
removing the knob, turning the spindle and replacing the knob.

Suggest you identify the shower and seek out an online manual.

wrote in message
...
Hi

We've had a thermostatic shower fitted - one of those where you turn
one dial to set the heat (notionally marked in deg C) and the other to
set the water flow strength.

But to get an acceptable temperature, the heat setting has to be set
as low as possible, otherwise it would scald. Is there likely to be
something that can be adjusted in the shower mixer so that the heat
markings are more closely approximate to the actual temperature being
output?

Probably not, but if so will be mentioned in the instructions which the
installer left with you.

For the record, I like a really hot shower, so its not just
me not able to handle the heat!

Hot water is supplied from a combi.


It might be more useful if you tell us where the cold is fed from.

You need to tell us the make and model of the shower mixer and who selected
it.

Jim A

On 25 Mar, 09:29, "Jim Alexander" wrote:
wrote in message

...

Hi

We've had a thermostatic shower fitted - one of those where you turn
one dial to set the heat (notionally marked in deg C) and the other to
set the water flow strength.

But to get an acceptable temperature, the heat setting has to be set
as low as possible, otherwise it would scald. *Is there likely to be
something that can be adjusted in the shower mixer so that the heat
markings are more closely approximate to the actual temperature being
output?

Probably not, but if so will be mentioned in the instructions which the
installer left with you.

For the record, I like a really hot shower, so its not just
me not able to handle the heat!

Hot water is supplied from a combi.

It might be more useful if you tell us where the cold is fed from.

You need to tell us the make and model of the shower mixer and who selected
it.

Jim A

We selected it (based on price), fitted by the plumber that worked on
other bits in the house when we had an extension done. Didn't really
test the temperature for ages as the tiling took a while to do.

I think its a tre mercati bar-type mixer. I'll try removing the end
tonight as well as searching for a manual online (certainly wasn't
left by the plumber unfortunately).

Thanks for the quick responses.

Matt

wrote in message
...
Hi

We've had a thermostatic shower fitted - one of those where you turn
one dial to set the heat (notionally marked in deg C) and the other to
set the water flow strength.

But to get an acceptable temperature, the heat setting has to be set
as low as possible, otherwise it would scald. Is there likely to be
something that can be adjusted in the shower mixer so that the heat
markings are more closely approximate to the actual temperature being
output? For the record, I like a really hot shower, so its not just
me not able to handle the heat!

Hot water is supplied from a combi.

Thanks!

Matt

Turn down the Combi DHW temperature.

wrote in message
...
On 25 Mar, 09:29, "Jim Alexander" wrote:
wrote in message

...

Hi

We've had a thermostatic shower fitted - one of those where you turn
one dial to set the heat (notionally marked in deg C) and the other to
set the water flow strength.

But to get an acceptable temperature, the heat setting has to be set
as low as possible, otherwise it would scald. Is there likely to be
something that can be adjusted in the shower mixer so that the heat
markings are more closely approximate to the actual temperature being
output?

Probably not, but if so will be mentioned in the instructions which the
installer left with you.

For the record, I like a really hot shower, so its not just
me not able to handle the heat!

Hot water is supplied from a combi.

It might be more useful if you tell us where the cold is fed from.

You need to tell us the make and model of the shower mixer and who
selected
it.

Jim A

We selected it (based on price), fitted by the plumber that worked on
other bits in the house when we had an extension done. Didn't really
test the temperature for ages as the tiling took a while to do.

I think its a tre mercati bar-type mixer. I'll try removing the end
tonight as well as searching for a manual online (certainly wasn't
left by the plumber unfortunately).

There is not an obvious thermostatic bar-type mixer on the Tre Mercati
website so I am puzzled. In my experience generic bar-type thermostatic
mixers work well with a wide range of supply pressures and also with
unbalanced supply pressures but not all thermosatic mixers work well with
unbalanced supplies. Specifically is the cold feed from the rising main or
from a header tank?

May seem obvious but have you checked that the mixer hot port is supplied
with hot? Difficult without the installation instructions of course.

Jim A

On 25 Mar, 12:17, "Jim Alexander" wrote:
wrote in message

...
On 25 Mar, 09:29, "Jim Alexander" wrote:





wrote in message

...

Hi

We've had a thermostatic shower fitted - one of those where you turn
one dial to set the heat (notionally marked in deg C) and the other to
set the water flow strength.

But to get an acceptable temperature, the heat setting has to be set
as low as possible, otherwise it would scald. Is there likely to be
something that can be adjusted in the shower mixer so that the heat
markings are more closely approximate to the actual temperature being
output?

Probably not, but if so will be mentioned in the instructions which the
installer left with you.

For the record, I like a really hot shower, so its not just
me not able to handle the heat!

Hot water is supplied from a combi.

It might be more useful if you tell us where the cold is fed from.

You need to tell us the make and model of the shower mixer and who
selected
it.

Jim A
We selected it (based on price), fitted by the plumber that worked on
other bits in the house when we had an extension done. *Didn't really
test the temperature for ages as the tiling took a while to do.
I think its a tre mercati bar-type mixer. *I'll try removing the end
tonight as well as searching for a manual online (certainly wasn't
left by the plumber unfortunately).

There is not an obvious thermostatic bar-type mixer on the Tre Mercati
website so I am puzzled. *In my experience generic bar-type thermostatic
mixers work well with a wide range of supply pressures and also with
unbalanced supply pressures but not all thermosatic mixers work well with
unbalanced supplies. *Specifically is the cold feed from the rising main or
from a header tank?

May seem obvious but have you checked that the mixer hot port is supplied
with hot? * Difficult without the installation instructions of course.

Jim A- Hide quoted text -

- Show quoted text -

Yes, I spotted that on the Tre site too....

I reckon hot must be supplied with hot as turning the dial down (in
deg C terms) does bring down the heat to a sensible temperature.

It did surprise me that it wasn't putting out closer to 38 degrees at
first as I'd imagined that there would indeed be some thermostatic
thingummyjig inside it which controlled the temperature; otherwise why
put the deg C on the dial in the first place?

Thinking about it, though, when it was installed I remember the guy
having some problems with excessive cold water supply such that he had
to fit some sort of valve on the cold water mains to reduce the
pressure. For some reason we've got two cold water mains in the house
too.

Matt

On 25 Mar, 10:58, "Doctor Drivel" wrote:
wrote in message

...





Hi

We've had a thermostatic shower fitted - one of those where you turn
one dial to set the heat (notionally marked in deg C) and the other to
set the water flow strength.

But to get an acceptable temperature, the heat setting has to be set
as low as possible, otherwise it would scald. *Is there likely to be
something that can be adjusted in the shower mixer so that the heat
markings are more closely approximate to the actual temperature being
output? *For the record, I like a really hot shower, so its not just
me not able to handle the heat!

Hot water is supplied from a combi.

Thanks!

Matt

Turn down the Combi DHW temperature.- Hide quoted text -

- Show quoted text -

Don't seem to be able to do that; certainly there isn't an obvious
dial on the Potterton Combi 100 that can be used to do this.

Turning down the cold water supply pressure might be the more
appropriate option though.

Matt

On Tue, 25 Mar 2008 06:43:46 -0700 (PDT) someone who may be
wrote this:-

Thinking about it, though, when it was installed I remember the guy
having some problems with excessive cold water supply such that he had
to fit some sort of valve on the cold water mains to reduce the
pressure. For some reason we've got two cold water mains in the house
too.

Even a thermostatic shower should be fed by supplies at nominally
the same pressure. One way of doing this is to take the cold from
the feed to the hot.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

wrote:
On 25 Mar, 10:58, "Doctor Drivel" wrote:

Turn down the Combi DHW temperature.


Don't seem to be able to do that; certainly there isn't an obvious
dial on the Potterton Combi 100 that can be used to do this.

Turning down the cold water supply pressure might be the more
appropriate option though.

Is there a problem with the cold supply to the shower mixer? Any restriction
in the pipework at a shut off valve or just too circuituous a route leading
to poor cold flow?

Must admit I'm surprised there's no DHW temperature control on it.

Tim

wrote:

Thinking about it, though, when it was installed I remember the guy
having some problems with excessive cold water supply such that he had
to fit some sort of valve on the cold water mains to reduce the
pressure.
For some reason we've got two cold water mains in the house
too.

Sounds like you need to get your plumber to sort it out as I think this is
the likely cause of the problem.

I'm guessing that the cold supply pressure (or more importantly FLOW) is now
a bit borderline for the mixer to create the mix of hot & cold that you
want.

I'm willing to be that rather than fit a pressure reducing valve, there will
be a simple stop-cock somewhere in the cold supply that supplies the shower
and it will be screwed down strangling the supply of cold to the shower
mixer.

Tim

On Tue, 25 Mar 2008 12:17:53 +0000, Jim Alexander wrote:

May seem obvious but have you checked that the mixer hot port is
supplied with hot? Difficult without the installation instructions of
course.

Not really: hots's on the left, cold on the right (looking at the front of
the shower, so vice versa looking at the pipework side)

--
John Stumbles

Extreme moderate

wrote:

But to get an acceptable temperature, the heat setting has to be set
as low as possible, otherwise it would scald. Is there likely to be

I take it you have checked that it is plumbed the right way round? (I.e.
the hot and cold feeds have not been swapped)


--
Cheers,

John.

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

On Tue, 25 Mar 2008 06:43:46 -0700, matthew.larkin wrote:

On 25 Mar, 12:17, "Jim Alexander" wrote:
wrote in message


...
On 25 Mar, 09:29, "Jim Alexander" wrote:





wrote in message

news:41f5935c-9a6b-4009-be86-
...

Hi

We've had a thermostatic shower fitted - one of those where you
turn one dial to set the heat (notionally marked in deg C) and the
other to set the water flow strength.

But to get an acceptable temperature, the heat setting has to be
set as low as possible, otherwise it would scald. Is there likely
to be something that can be adjusted in the shower mixer so that
the heat markings are more closely approximate to the actual
temperature being output?

Probably not, but if so will be mentioned in the instructions which
the installer left with you.

For the record, I like a really hot shower, so its not just me not
able to handle the heat!

Hot water is supplied from a combi.

It might be more useful if you tell us where the cold is fed from.

You need to tell us the make and model of the shower mixer and who
selected
it.

Jim A
We selected it (based on price), fitted by the plumber that worked on
other bits in the house when we had an extension done. Â*Didn't really
test the temperature for ages as the tiling took a while to do. I
think its a tre mercati bar-type mixer. Â*I'll try removing the end
tonight as well as searching for a manual online (certainly wasn't
left by the plumber unfortunately).

There is not an obvious thermostatic bar-type mixer on the Tre Mercati
website so I am puzzled. Â*In my experience generic bar-type
thermostatic mixers work well with a wide range of supply pressures and
also with unbalanced supply pressures but not all thermosatic mixers
work well with unbalanced supplies. Â*Specifically is the cold feed from
the rising main or from a header tank?

May seem obvious but have you checked that the mixer hot port is
supplied with hot? Â* Difficult without the installation instructions of
course.

Jim A- Hide quoted text -

- Show quoted text -

Yes, I spotted that on the Tre site too....

I reckon hot must be supplied with hot as turning the dial down (in deg
C terms) does bring down the heat to a sensible temperature.

It did surprise me that it wasn't putting out closer to 38 degrees at
first as I'd imagined that there would indeed be some thermostatic
thingummyjig inside it which controlled the temperature; otherwise why
put the deg C on the dial in the first place?

Thinking about it, though, when it was installed I remember the guy
having some problems with excessive cold water supply such that he had
to fit some sort of valve on the cold water mains to reduce the
pressure. For some reason we've got two cold water mains in the house
too.

Matt

It might just need calibrating (i.e resetting the position of the temp
knob to cover the range you want). The intructions when you've found them
will help. Or careful and thoughtful investigation of how the knobs are
fitted.


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://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
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html

On 25 Mar, 14:29, "Tim Downie"
wrote:
wrote:
Thinking about it, though, when it was installed I remember the guy
having some problems with excessive cold water supply such that he had
to fit some sort of valve on the cold water mains to reduce the
pressure.
For some reason we've got two cold water mains in the house
too.

Sounds like you need to get your plumber to sort it out as I think this is
the likely cause of the problem.

I'm guessing that the cold supply pressure (or more importantly FLOW) is now
a bit borderline for the mixer to create the mix of hot & cold that you
want.

I'm willing to be that rather than fit a pressure reducing valve, there will
be a simple stop-cock somewhere in the cold supply that supplies the shower
and it will be screwed down strangling the supply of cold to the shower
mixer.

Tim

Had a look at the pressure valve last night for the cold water feed
that feeds the shower, and that is showing as restricted to a pressure
of 3 bar. I'll try increasing that slowly tonight to see if I can get
to a more optimal shower temperature range.

Matt

wrote in message
...
On 25 Mar, 14:29, "Tim Downie"
wrote:
wrote:
Thinking about it, though, when it was installed I remember the guy
having some problems with excessive cold water supply such that he had
to fit some sort of valve on the cold water mains to reduce the
pressure.
For some reason we've got two cold water mains in the house
too.

Sounds like you need to get your plumber to sort it out as I think this
is
the likely cause of the problem.

I'm guessing that the cold supply pressure (or more importantly FLOW) is
now
a bit borderline for the mixer to create the mix of hot & cold that you
want.

I'm willing to be that rather than fit a pressure reducing valve, there
will
be a simple stop-cock somewhere in the cold supply that supplies the
shower
and it will be screwed down strangling the supply of cold to the shower
mixer.

Tim

Had a look at the pressure valve last night for the cold water feed
that feeds the shower, and that is showing as restricted to a pressure
of 3 bar. I'll try increasing that slowly tonight to see if I can get
to a more optimal shower temperature range.

If you like but 3 bar is a perfectly reasonable pressure setting for a PRV
on a cold feed. Anyway it's the pressure/flow at the shower cold port not
the PRV which may be the issue. Have you verified it's on the rising main
and not a header tank? Have you verified the shower is connected the right
way round?

Either you have a faulty mixer or a faulty installation. Both callback
issues.

Jim A

On 26 Mar, 09:40, "Jim Alexander" wrote:
wrote in message

...





On 25 Mar, 14:29, "Tim Downie"
wrote:
wrote:
Thinking about it, though, when it was installed I remember the guy
having some problems with excessive cold water supply such that he had
to fit some sort of valve on the cold water mains to reduce the
pressure.
For some reason we've got two cold water mains in the house
too.

Sounds like you need to get your plumber to sort it out as I think this
is
the likely cause of the problem.

I'm guessing that the cold supply pressure (or more importantly FLOW) is
now
a bit borderline for the mixer to create the mix of hot & cold that you
want.

I'm willing to be that rather than fit a pressure reducing valve, there
will
be a simple stop-cock somewhere in the cold supply that supplies the
shower
and it will be screwed down strangling the supply of cold to the shower
mixer.

Tim

Had a look at the pressure valve last night for the cold water feed
that feeds the shower, and that is showing as restricted to a pressure
of 3 bar. *I'll try increasing that slowly tonight to see if I can get
to a more optimal shower temperature range.

If you like but 3 bar is a perfectly reasonable pressure setting for a PRV
on a cold feed. *Anyway it's the pressure/flow at the shower cold port not
the PRV which may be the issue. * Have you verified it's on the rising main
and not a header tank? *Have you verified the shower is connected the right
way round?

Either you have a faulty mixer or a faulty installation. *Both callback
issues.

Jim A- Hide quoted text -

- Show quoted text -

There's no header tank in the house. Other than saying that the
temperature does decrease as the dial is turned as I'd expect, I can't
check if the hot goes to the cold and vice versa, but I'd say that was
extremely unlikely given the first part of this sentence.

You're probably right about the callback, just thought I'd see if
there was an easy diy fix instead.

Thanks

Matt

On Wed, 26 Mar 2008 03:46:58 -0700 (PDT) someone who may be
wrote this:-

Other than saying that the
temperature does decrease as the dial is turned as I'd expect, I can't
check if the hot goes to the cold and vice versa,

There should be. As it is a bar type shower one side/end should be
hot when it is running and one end cold. The nuts where it fastens
to the pipes are a good place to test on many such showers, or the
ends of the bar if it is a more fancy type.

It is a fair certainty that the left hand side should be the hot one
and the right hand side the cold.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

On 26 Mar, 11:20, David Hansen
wrote:
On Wed, 26 Mar 2008 03:46:58 -0700 (PDT) someone who may be
wrote this:-

Other than saying that the
temperature does decrease as the dial is turned as I'd expect, I can't
check if the hot goes to the cold and vice versa,

There should be. As it is a bar type shower one side/end should be
hot when it is running and one end cold. The nuts where it fastens
to the pipes are a good place to test on many such showers, or the
ends of the bar if it is a more fancy type.

It is a fair certainty that the left hand side should be the hot one
and the right hand side the cold.

--
* David Hansen, Edinburgh
*I will *always* explain revoked encryption keys, unless RIP prevents me
*http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

Fair enough, though as I've said given that the dial does have the
right logical effect on the water temperature, I'm reasonably certain
that it is plumbed the right way round!

Matt

wrote in message
...
On 26 Mar, 11:20, David Hansen
wrote:
On Wed, 26 Mar 2008 03:46:58 -0700 (PDT) someone who may be
wrote this:-

Other than saying that the
temperature does decrease as the dial is turned as I'd expect, I can't
check if the hot goes to the cold and vice versa,

There should be. As it is a bar type shower one side/end should be
hot when it is running and one end cold. The nuts where it fastens
to the pipes are a good place to test on many such showers, or the
ends of the bar if it is a more fancy type.

It is a fair certainty that the left hand side should be the hot one
and the right hand side the cold.

--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

Fair enough, though as I've said given that the dial does have the
right logical effect on the water temperature, I'm reasonably certain
that it is plumbed the right way round!

Beg to differ. Done a quick test on my bar mixer. Isolated the hot side at
the service valve. At full temp no cold flows. That's logical. At minimum
temperature a good flow of cold, also logical. But you have to consider how
a combi delivers hot water. Depending on how your combi is set up but
typically at low flow rate the delivered temperature is higher than at
higher flow rate which is what your are reporting. One symptom, two
possible explanations.

We are trying to help but in the face of the problem you ought to at least
test our theories. You did ask.

Jim A

On 26 Mar, 12:06, "Jim Alexander" wrote:
wrote in message

...
On 26 Mar, 11:20, David Hansen
wrote:





On Wed, 26 Mar 2008 03:46:58 -0700 (PDT) someone who may be
wrote this:-

Other than saying that the
temperature does decrease as the dial is turned as I'd expect, I can't
check if the hot goes to the cold and vice versa,

There should be. As it is a bar type shower one side/end should be
hot when it is running and one end cold. The nuts where it fastens
to the pipes are a good place to test on many such showers, or the
ends of the bar if it is a more fancy type.

It is a fair certainty that the left hand side should be the hot one
and the right hand side the cold.

--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54
Fair enough, though as I've said given that the dial does have the
right logical effect on the water temperature, I'm reasonably certain
that it is plumbed the right way round!

Beg to differ. *Done a quick test on my bar mixer. *Isolated the hot side at
the service valve. *At full temp no cold flows. *That's logical. *At minimum
temperature a good flow of cold, also logical. *But you have to consider how
a combi delivers hot water. *Depending on how your combi is set up but
typically at low flow rate the delivered temperature is higher than at
higher flow rate which is what your are reporting. *One symptom, two
possible explanations.

We are trying to help but in the face of the problem you ought to at least
test our theories. *You did ask.

Jim A- Hide quoted text -

- Show quoted text -

OK, I can buy that; I'll test tonight and put to good use all the
input you've provided! I didn't mean to give the impression that I
was coming to the group and then blithely ignoring the advice of those
that know significantly better than I do (but if that was the
impression I gave, then please accept my correction!!).

Thanks!

Matt

In article ,
David Hansen writes:
Even a thermostatic shower should be fed by supplies at nominally
the same pressure. One way of doing this is to take the cold from
the feed to the hot.

A thermostatic shower designed for combi/multipoint use will take
high pressure cold and widely varying pressure hot. It also has a
very rapid response to hot water temperature changes.

A thermostatic shower not designed for combi/multipoint use can
behave very strangely when used with one, because it doesn't
respond fast enough and will try to vary the water temperature
by changing the hot flow which usually doesn't work.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]