Thermostatic Bar shower and water temp changing whilst in use solution?

I think I’ve seen it on here before but can’t remember ….

The hot water on my shower keeps going cold intermittently, or we need to turn the heat up more than we used to to get the required temp. Doesn’t happen on the new one I’ve just fitted in the kids bathroom and its exactly the same shower I have fitted in my en suite except mine is a couple of years older. Is there something that goes or needs cleaning on the thermostatic side of the bar?

Mine has started doing this, so watching with interest. In my case I’d assumed maybe a limescale issue?(chalky north Hampshire)

The thermostatic valves need taking out and cleaning every now and then. Once a year or so, depending on how hard your water is. Soaking them in white vinegar or citric acid solution lifts off any limescale. Sometimes the silicone o-rings wear/tear too and need replacing. Also on mine, if you remove the on/off tap you can adjust the maximum temperature with an Allen key. You can even do it whilst the shower is running.

Cool, cheers @blokeuptheroad I’ll give that a go. Knew it’d be a pretty simple solution.

It might just need cleaning, but they do fail and (certainly in any from a decent manufacturer) they’re an easily replaceable unit (though not cheap)

I replaced a Triton cartridge (official replacement wickedly expensive) with an eBay compatible one (£18) and it’s been fine for years.

Be aware, if it is a basic bar mixer, they are less than £50 new if you shop around.The cartridges can cost more than a new complete mixer. Also, they can be a real pain to repair, the threads get limescaled up and its difficult to remove them, and when put back, they dont always seal properly. Changing the complete bar mixer is a 10 minute job, turn off the water (H+C), undo the two large nuts, and its off. We had an expensive Bristan one fail after 8 months, the cheap one we replaced it with from travis Perkins was aroudn £45, and has lasted 3 years now.

I replaced the thermostatic cartridge on mine after it wouldn’t regulate the temperature properly.

Think its Bristan and screwfix stocked the part

I’ll open it up and have a look first. Hopefully it’ll clean up. Don’t want to get a new bar as it’s a full set with rigid external pipework and stuff. I’ve fitted a few before so know how to do it, including this one a couple.of years ago, but would rather get this one working.