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Lobster
 
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Default Faulty thermostats in bar shower valves

We have two identical bar mixer shower valves (similar to the following:
http://www.screwfix.com/app/sfd/cat/...81667&id=21764)
in which the thermostats both recently seem to have stopped working
properly. Both about 4 yrs old, came from Screwfix originally.

In one shower, the temperature seems balanced on a knife-edge; you now
only have to touch the control to send the temp up or down by a large
amount. Although it does at least stay stable once you've managed to get
it to a comfortable temperature.

In the second one, you have to over-ride the safety button (which is a
simple feature set at an indicated 38 deg C, to stop the user from
accidentally cranking up the temp to a dangerously high level without
realising). It needs to be turned right up almost to max (an indicated
45-50 deg C) regardless of actual incoming HW temp. Again, it does
appear stable once it's working.

What can go wrong with a simple stat like this to cause these
(different) symptoms? Can they be repaired/replaced without changing
the whole shower valve? Haven't tried dismantling them yet so don't
know what's inside them...

Thanks
David
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Pete C
 
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On Tue, 01 Mar 2005 15:52:31 GMT, Lobster
wrote:

We have two identical bar mixer shower valves (similar to the following:
http://www.screwfix.com/app/sfd/cat/...81667&id=21764)
in which the thermostats both recently seem to have stopped working
properly. Both about 4 yrs old, came from Screwfix originally.

In one shower, the temperature seems balanced on a knife-edge; you now
only have to touch the control to send the temp up or down by a large
amount. Although it does at least stay stable once you've managed to get
it to a comfortable temperature.

In the second one, you have to over-ride the safety button (which is a
simple feature set at an indicated 38 deg C, to stop the user from
accidentally cranking up the temp to a dangerously high level without
realising). It needs to be turned right up almost to max (an indicated
45-50 deg C) regardless of actual incoming HW temp. Again, it does
appear stable once it's working.

What can go wrong with a simple stat like this to cause these
(different) symptoms? Can they be repaired/replaced without changing
the whole shower valve? Haven't tried dismantling them yet so don't
know what's inside them...

Thanks
David


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Geoff Norfolk
 
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Default

Funny you should mention this.................. mine, again from Screwfix
and about 2 years old, has gone exactly the same way. Took out the end with
the thermostat etc in but couldn't see a way of getting it open so put some
descaler in it.............. didn't make a scrap of difference! I've now
just bought a Mira 88 Gem through Ebay for £80.............must have fallen
off the back of a lorry! The annoying thing is the connection aren't the
same so there's a lot of work breaking out the connections set in the wall
behind the tiles. That Screwfix wasn't as good value as appeared!!

Geoff
"Pete C" wrote in message
...
On Tue, 01 Mar 2005 15:52:31 GMT, Lobster
wrote:

We have two identical bar mixer shower valves (similar to the following:
http://www.screwfix.com/app/sfd/cat/...81667&id=21764)
in which the thermostats both recently seem to have stopped working
properly. Both about 4 yrs old, came from Screwfix originally.

In one shower, the temperature seems balanced on a knife-edge; you now
only have to touch the control to send the temp up or down by a large
amount. Although it does at least stay stable once you've managed to get
it to a comfortable temperature.

In the second one, you have to over-ride the safety button (which is a
simple feature set at an indicated 38 deg C, to stop the user from
accidentally cranking up the temp to a dangerously high level without
realising). It needs to be turned right up almost to max (an indicated
45-50 deg C) regardless of actual incoming HW temp. Again, it does
appear stable once it's working.

What can go wrong with a simple stat like this to cause these
(different) symptoms? Can they be repaired/replaced without changing
the whole shower valve? Haven't tried dismantling them yet so don't
know what's inside them...

Thanks
David




  #4   Report Post  
John
 
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Default


"Lobster" wrote in message
...
We have two identical bar mixer shower valves (similar to the following:
http://www.screwfix.com/app/sfd/cat/...81667&id=21764)
in which the thermostats both recently seem to have stopped working
properly. Both about 4 yrs old, came from Screwfix originally.

Are you in a hard water area. Scaling up will stop the thermostats working
properly. Not sure if it possible to descale, I tried but finished up with
new ones.
john


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Lobster
 
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Default

John wrote:
"Lobster" wrote in message
...

We have two identical bar mixer shower valves (similar to the following:
http://www.screwfix.com/app/sfd/cat/...81667&id=21764)
in which the thermostats both recently seem to have stopped working
properly. Both about 4 yrs old, came from Screwfix originally.


Are you in a hard water area. Scaling up will stop the thermostats working
properly. Not sure if it possible to descale, I tried but finished up with
new ones.


No, very soft water: I should have mentioned that!
Are yours the same type of shower? ie, if I dismantle, is there a
"component" inside which can be renewed? I doubt they would be generic,
or would they... where would i get replacments? Can't see S'fix being
of much help here!

Thanks
David


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Christian McArdle
 
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Default

What can go wrong with a simple stat like this to cause these
(different) symptoms? Can they be repaired/replaced without changing
the whole shower valve? Haven't tried dismantling them yet so don't
know what's inside them...


I had a similar valve, but not from Screwfix. Same symptoms (the needing to
turn up high) until it got so bad it went tepid. Descaling didn't work. I
sold the house. A bit of a drastic solution, I suppose...

Christian.


  #7   Report Post  
Pete C
 
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On Tue, 01 Mar 2005 17:07:11 +0000, Pete C
wrote:

On Tue, 01 Mar 2005 15:52:31 GMT, Lobster
wrote:

We have two identical bar mixer shower valves (similar to the following:
http://www.screwfix.com/app/sfd/cat/...81667&id=21764)
in which the thermostats both recently seem to have stopped working
properly. Both about 4 yrs old, came from Screwfix originally.

In one shower, the temperature seems balanced on a knife-edge; you now
only have to touch the control to send the temp up or down by a large
amount. Although it does at least stay stable once you've managed to get
it to a comfortable temperature.

In the second one, you have to over-ride the safety button (which is a
simple feature set at an indicated 38 deg C, to stop the user from
accidentally cranking up the temp to a dangerously high level without
realising). It needs to be turned right up almost to max (an indicated
45-50 deg C) regardless of actual incoming HW temp. Again, it does
appear stable once it's working.

What can go wrong with a simple stat like this to cause these
(different) symptoms? Can they be repaired/replaced without changing
the whole shower valve? Haven't tried dismantling them yet so don't
know what's inside them...


Hi,

Is it possible to find out from Screwfix who the original manufacturer
is?

It sounds like the wax capsule is getting 'stuck', maybe the
manufacturer would have some ideas on how to cure it, a suitable
grease perhaps.

Also are these on a combi boiler?

cheers,
Pete.
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Lobster
 
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Pete C wrote:
On Tue, 01 Mar 2005 17:07:11 +0000, Pete C
wrote:

On Tue, 01 Mar 2005 15:52:31 GMT, Lobster
wrote:


We have two identical bar mixer shower valves (similar to the following:
http://www.screwfix.com/app/sfd/cat/...81667&id=21764)
in which the thermostats both recently seem to have stopped working
properly. Both about 4 yrs old, came from Screwfix originally.


Is it possible to find out from Screwfix who the original manufacturer
is?


You'd think so, but no - they've stopped flogging it now and have no
details on it. Also, as far as Screwfix are concerned they're out of
warranty (wondered if there might be a 5-year one, but they say they'd
have kept a record of that were it the case... hmm.)

It sounds like the wax capsule is getting 'stuck', maybe the
manufacturer would have some ideas on how to cure it, a suitable
grease perhaps.


Sounds like I'd better pull the things to bits, doesn't it?? How do
these wax capsules work/are they dismantleable or anything?

Also are these on a combi boiler?


No, we have an unvented HW system (why do you ask?)

Thanks
David
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Pete C
 
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On Wed, 02 Mar 2005 19:32:59 GMT, Lobster
wrote:


You'd think so, but no - they've stopped flogging it now and have no
details on it. Also, as far as Screwfix are concerned they're out of
warranty (wondered if there might be a 5-year one, but they say they'd
have kept a record of that were it the case... hmm.)


There's a few shower spares places on the web, may be worth emailing a
pic of it and any details of markings, purchase date from
Screwix/stock no, etc:

http://www.showerdoc.co.uk/index.html
http://www.shower-spares.co.uk/

Also there is a forum on the Screwfix site, someone there may have an
old catalog which says who its made by or even how long the guarantee
is.

Sounds like I'd better pull the things to bits, doesn't it?? How do
these wax capsules work/are they dismantleable or anything?


The above companies might be able to help on that one.

OTOH there are some inexpensive mixers on Ebay and one from
Toolstation with 5yr guarentee costing £60 so it may not be worth
fixing it. Even if you can obtain an original replacement it may
suffer from the same problem again.

Maybe pouring some descaler in when it's cold then repeating it after
the valve has been warmed up, by setting it to the highest temperature
or dropping it in a pan of hand hot water would help.

Also are these on a combi boiler?


No, we have an unvented HW system (why do you ask?)


I just wondered if a combi could allow too-hot water to reach the
shower.

One other thing, check any strainers on the inlet are not blocked.

cheers,
Pete.
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Lobster
 
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Pete C wrote:

lots of useful suggestions snipped

Many thanks for that Pete, I'll certainly look into these.

OTOH there are some inexpensive mixers on Ebay and one from
Toolstation with 5yr guarentee costing £60 so it may not be worth
fixing it. Even if you can obtain an original replacement it may
suffer from the same problem again.


Followup q: is the separation of the H and C pipes on a shower mixer bar
standard? Having only finished retiling the shower a few weeks back I
think I might spontaneously combust if faced with changing the mixer for
one of different dimensions...

David


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Pete C
 
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On Fri, 04 Mar 2005 00:13:55 GMT, Lobster
wrote:

Followup q: is the separation of the H and C pipes on a shower mixer bar
standard? Having only finished retiling the shower a few weeks back I
think I might spontaneously combust if faced with changing the mixer for
one of different dimensions...


Hi,

I've got no idea to be honest but if the bar mixer is fairly recent,
I'd expect there is a good chance that one with the same spacing is
available.

cheers,
Pete.
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Pete C
 
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On Fri, 04 Mar 2005 00:13:55 GMT, Lobster
wrote:


Followup q: is the separation of the H and C pipes on a shower mixer bar
standard? Having only finished retiling the shower a few weeks back I
think I might spontaneously combust if faced with changing the mixer for
one of different dimensions...

David


Hi,

Just got a new mixer today, the centres are 150mm. To get the innards
and the capsule out there are little caps on each handle that prise
off to uncover a screwhead underneath.

One other thing, there are a couple of non return valves on the
inlets, if these are getting jammed on yours it might cause problems.

cheers,
Pete.
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Lobster
 
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Pete C wrote:
On Wed, 02 Mar 2005 19:32:59 GMT, Lobster
wrote:

You'd think so, but no - they've stopped flogging it now and have no
details on it. Also, as far as Screwfix are concerned they're out of
warranty (wondered if there might be a 5-year one, but they say they'd
have kept a record of that were it the case... hmm.)


Also there is a forum on the Screwfix site, someone there may have an
old catalog which says who its made by or even how long the guarantee
is.


Pete, you're a star... I followed the above advice and came up trumps: I
found another S'fix punter who had fitted the same shower as me, and had
actually kept the box, which was emblazoned with a 5-year guarantee!

So I've just come off the phone with Screwfix and am eagerly awaiting
the delivery of two new units (delivered separately, of course; followed
by two more visits next day to collect the duff valves! And yet another
visit to replace the unrelated item which arrived this morning smashed
to smithereens...)

Very many thanks for the advice
David
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Pete C
 
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On Tue, 08 Mar 2005 20:02:43 GMT, Lobster
wrote:

Pete, you're a star... I followed the above advice and came up trumps: I
found another S'fix punter who had fitted the same shower as me, and had
actually kept the box, which was emblazoned with a 5-year guarantee!

So I've just come off the phone with Screwfix and am eagerly awaiting
the delivery of two new units (delivered separately, of course; followed
by two more visits next day to collect the duff valves! And yet another
visit to replace the unrelated item which arrived this morning smashed
to smithereens...)

Very many thanks for the advice


LOL! Nice one!

cheers,
Pete.
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