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Faulty thermostats in bar shower valves

We have two identical bar mixer shower valves (similar to the following:

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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

Reply to
Lobster
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Reply to
Pete C

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!!

Reply to
Geoff Norfolk

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

Reply to
John

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

Reply to
Lobster

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.

Reply to
Christian McArdle

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.

Reply to
Pete C

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.)

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

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

Thanks David

Reply to
Lobster

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:

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.

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.

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.

Reply to
Pete C

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

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

Reply to
Lobster

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.

Reply to
Pete C

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.

Reply to
Pete C

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

Reply to
Lobster

LOL! Nice one!

cheers, Pete.

Reply to
Pete C

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