Can anyone identify this shower please

silvercar

I need the make and model to identify a new thermostat 

ThisIsWeird

Google 'lens' comes up with lots of this type of shower mixer. Yours is distinctive, tho', by having these decorative ridges on the handles, but that doesn't help to narrow it down!

Chances are, the internals will be similar to most of the ones you see which are essentially the same style; the thermo cartridges, especially, tend to be a shared type; manufacturers tend to 'buy them in'.

Can you isolate the supply to the shower easily? Cool. What I'd do is to find the instructions for a similar model, find out how to dismantle it (most likely by removing the chrome handle, and unscrewing the cartridge), take photos and measurements of what's in your hand, and then searching for one of them.

Are you in a hard water area? If so, perhaps meanwhile soak the cartridge in limescale remover or vinegar, and see if that sorts it.

Eg: https://www.ergonomicdesigns.co.uk/uploads/install/SOLS31C_install.pdf

silvercar

No way of easy isolating it, so I’ve called in a plumber. He’s said unless I can identify it, it will probably mean a whole new unit.

I’ts 17 years old, goes hot then cold, then hot again without holding the hot for very long. Our water softener has been back on for 2 months since we’ve had building works done, most other things have lost the lime scale they gained while it was switched off, so it’s probably more than a bit of limescale.

nofoollikeold

1. What sort of boiler do you have?
2. If combi:
2.1 Switch off central heating, or set room thermostat very high.
2.2 Get someone to watch the boiler while the shower runs.  See if the boiler stops firing in sync (or thereabouts) with the shower running cold.
2.3 If so, may be insufficient hot water flow to keep boiler running.  Could possibly be choked filter in shower, or scaled up secondary heat exchanger in boiler.
3. If not combi, likely to be problem with shower.  If fitted, clean filter and non-return valve.

silvercar

nofoollikeold said:

1. What sort of boiler do you have?
2. If combi:
2.1 Switch off central heating, or set room thermostat very high.
2.2 Get someone to watch the boiler while the shower runs.  See if the boiler stops firing in sync (or thereabouts) with the shower running cold.
2.3 If so, may be insufficient hot water flow to keep boiler running.  Could possibly be choked filter in shower, or scaled up secondary heat exchanger in boiler.
3. If not combi, likely to be problem with shower.  If fitted, clean filter and non-return valve.

It is a combi. The combi is quite old, but there is no problem with the heating at the moment, would it show itself on other taps? I’ve noticed that turning the shower flow down can improve the temperature, so I doubt there is insufficient flow., though that could be my imagination.

ThisIsWeird

silvercar said:

No way of easy isolating it, so I’ve called in a plumber. He’s said unless I can identify it, it will probably mean a whole new unit.

I’ts 17 years old, goes hot then cold, then hot again without holding the hot for very long. Our water softener has been back on for 2 months since we’ve had building works done, most other things have lost the lime scale they gained while it was switched off, so it’s probably more than a bit of limescale.

Interesting...
NFLO may be on to something. The temp fluctuation betwixt hot and cold is classic blocked P2P heat exchanger in a combi, so his test is Def worth carrying out. Paying - what? - £150+? for a new mixer, only to find no improvement will be a touch irritating. 
I have found that a faulty thermo cartridge usually means the temp cannot be adjusted by very much, but repeated swings between h&C with you not touching the controls shouts P2P. It all comes down to whether the boiler shuts off each time, as NoFool says.

silvercar

ThisIsWeird said:

silvercar said:

No way of easy isolating it, so I’ve called in a plumber. He’s said unless I can identify it, it will probably mean a whole new unit.

I’ts 17 years old, goes hot then cold, then hot again without holding the hot for very long. Our water softener has been back on for 2 months since we’ve had building works done, most other things have lost the lime scale they gained while it was switched off, so it’s probably more than a bit of limescale.

Interesting...
NFLO may be on to something. The temp fluctuation betwixt hot and cold is classic blocked P2P heat exchanger in a combi, so his test is Def worth carrying out. Paying - what? - £150+? for a new mixer, only to find no improvement will be a touch irritating. 
I have found that a faulty thermo cartridge usually means the temp cannot be adjusted by very much, but repeated swings between h&C with you not touching the controls shouts P2P. It all comes down to whether the boiler shuts off each time, as NoFool says.

If it only happens with the shower and not on any taps, could it still be the boiler?

ThisIsWeird

silvercar said:

ThisIsWeird said:

silvercar said:

No way of easy isolating it, so I’ve called in a plumber. He’s said unless I can identify it, it will probably mean a whole new unit.

I’ts 17 years old, goes hot then cold, then hot again without holding the hot for very long. Our water softener has been back on for 2 months since we’ve had building works done, most other things have lost the lime scale they gained while it was switched off, so it’s probably more than a bit of limescale.

Interesting...
NFLO may be on to something. The temp fluctuation betwixt hot and cold is classic blocked P2P heat exchanger in a combi, so his test is Def worth carrying out. Paying - what? - £150+? for a new mixer, only to find no improvement will be a touch irritating. 
I have found that a faulty thermo cartridge usually means the temp cannot be adjusted by very much, but repeated swings between h&C with you not touching the controls shouts P2P. It all comes down to whether the boiler shuts off each time, as NoFool says.

If it only happens with the shower and not on any taps, could it still be the boiler?

That's a good point - it should happen with both. But, it's often only noticed when running a shower or bath, as only then will the hot will be running for long enough to cause what is overheating in the boiler. You would typically have to have the hot running constantly for a minuteish or so.
But, it's only a possibility, of course.
Try NF's test - have someone watching the boiler when the shower is run. Ask the showeree to shout (won't be hard) when it goes cold, but if it's the P2P, you'll be shouting to them instead - "You're gonna go cold in 5 seconds...".

ThisIsWeird

Does the temp control feel smooth in operation?

silvercar

Boiler tested while shower was on, the boiler stays on the whole time the shower was on.

(Over) analysis by OH. The temperature gets hot, then cools down to warm and stay within a small range that he describes as warm, not hot enough and fluctuating within that range for the whole time.

The temp control is smooth.

ThisIsWeird

silvercar said:

Boiler tested while shower was on, the boiler stays on the whole time the shower was on.

(Over) analysis by OH. The temperature gets hot, then cools down to warm and stay within a small range that he describes as warm, not hot enough and fluctuating within that range for the whole time.

The temp control is smooth.

Thanks. Just to confirm - the boiler stays on with its flame symbol or green 'burner' light always on? (Does it have one of these?!)
If so, it would certainly seem to be a shower mixer issue, and therefore most likely the thermo cartridge, tho' could be as simple as a partially blocked filter in its supply, usually fitted where the pipes connect.
Are you up for some DIY?