Thermostatic Shower goes Cold

[RodMartin]

I have a Grohe thermostatic shower. It is about 2 years old.

Nowadays, it starts warm (cant say Hot) and after 1 or 2 mins goes cold. When it was new it would do the same but start hot and go warm.

There is plenty of hot water (the sink still has hot water).

Help!

 

[clf-gas]

Does it have a cartridge, may be faulty.

 

[RodMartin]

Possible/Probably

How do I find out and how do I replace it.

I can send a photo of the unit, but it is a typical Grohe thermostatic valve with two knobs. top on/off lower temperature.

[email protected]

 

[RigidRaider]

Are you in a hard water area? The symptoms are of a wax cartrige that is being affected by calcification. If you contact Grohe I bet they will advise you to remove the cartridge, soak it in descaler, flush and replace. It should be possible to do this without turning off the water; there may be small valves on the front of your shower valve.

 

[RodMartin]

I will try this, because yes we are in a very hard water area and the problem has got worse.

I can turn the water off just to the bathroom at the pump, so not a problem. Not sure what valve you mean though. The type is a 34932 000. The one with two knobs above each other on a chrome oval. Upper is on/off lower is thermostat.

I presume I undo the central nut to remove the catridge with all the chrome stuff removed. Is it worth cleaning the strainer too?
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[RigidRaider]

Your valve sounds like our Eurobath valve. Their advice is to gently pull off the two knobs, undo the retaining rings and remove the wall plate then remove the temperature control valve- TBH I don't know how this is done but I'd guess you undo a locking ring or unscrew the cartridge. And yes, they advise soaking in descaler then flushing and cleaning the filters. Eurobath say it's a common problem and the cartridge can usually be revived successfully.