I have a Grohe mixer (I'm not exactly sure which model - perhaps a 1000 or 2000? - maybe you can tell from the photo). The shower worked perfectly for about a year since I moved in, now it is generally luke warm or cold. It never gets hot.
I've been doing some diagnoses as follows:
* I have a combi boiler and elsewhere in the flat the water is piping hot (from all the taps, including the basin in the bathroom)
* There are two screws right and left which seem to adjust the pressure of the incoming water (cold and hot respectively). When I turn the right hand screw down I can get the temperature to rise but then the pressure drops right off and sometimes it's not even enough to draw the combi boiler on - defeating the object
* I did an experiment: I took the cartridge out and rigged up a plastic tube to carry the water safely away, then I turned the water back on without the cartridge in place. The water flowed at a decent rate and when I tuned the right hand screw down a bit, the water ran hot
So I suspect my problem is that inexplicably the cold water pressure has increased to the point where the thermostat can no longer balance the temperature properly?
My problem is that I assume what I really need to do is put a flow limiter in the cold flow to the shower. Except the connector is behind my tiles - is there anything I can do to except add a flow limiter? Might a new thermostat be able to balance the flow rates better? Can I try and partially block the cold flow behind the right screw to help?
Any ideas which don't require me to destroy my bathroom very welcome.