Changing shower/Bath valve thermostatic cartridge
Changing shower/Bath valve thermostatic cartridge
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Discussion

Blown2CV

Original Poster:

30,990 posts

227 months

Friday 3rd June 2011
quotequote all
I have one of those single unit bath/shower valves, and the temperature has gone nuts, I have established that the thermostat cartridge needs changing. The fact that it is only 3yr old grates me, but that is another story - apparently they are classified as a consumable item... The part is £75. Plumber quoted me nearly 3 times that. Is it something a relatively incompetent DIYer can do? I am told the water needs to be turned off (obv) but this can be done inside the valve with the cover off...

Flintstone

8,644 posts

271 months

Friday 3rd June 2011
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Not sure which brand you have but if it's anything like mine you can do it fairly easily but no, there's no way to shut off the water within the unit.

Took me about 20 minutes.

dave_s13

13,991 posts

293 months

Friday 3rd June 2011
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I had to change one on my Mira shower. The old one bust with frost damage when the house was stood empty during an extension. Mira actually gave me one free as the shower had never actually been used....anyway.

It was just a matter of unscrewing the tap, and then unscrewing the cartridge. What make is yours, is there an online installation guide you can download?

Just turn water off at your main IV, run the downstairs taps to drain the water out.

Dead easy really.

Blown2CV

Original Poster:

30,990 posts

227 months

Friday 3rd June 2011
quotequote all
mfr is crosswater, but the unit is a bathstore branded one. Mira apparently are nicer about warrantying these items. Crosswater and Bathstore are arses. It was Crosswater tech support that told me that the water could be shut off from behind the valve front plate. The reason for me asking on this thread is because Crosswater were a bit hazy about how much skill was required.

Gingerbread Man

9,173 posts

237 months

Friday 3rd June 2011
quotequote all
By the sounds of it, you have a valve sat in your wall with 2 or 3 knobs coming out of it through a face plate? Quite popular with Crosswater.

The face plate should come off to reveal the valve. Two inputs - hot in and cold in and then either one or two outs, maybe shower rail handset and the other to a rain head for example.

To remove the face plate, it's either via screws on the plate, or siliconed on, which makes life a pain in the arse.
You may have to remove the knobs first. Normally via allen key grub screws on the side.

As for isolating the water at the valve, you can balence the inputs via slot headed bias valves. If wound right in, these would cut the incoming flow. To be honest, if this is what he means, I'd tend to isolate at the cylinder/ tank.
If you choose to isolate it at the shower valve's bias valves, keep a note of how many turns they both are to off, or you'll throw the calibration.