TT built in thermostatic shower valve A3969
However first you need to remove the covers if you have a look at the above link this should give you an idea of how they go together.
There is a black button on the temperature control carrier this needs to be slipped side ways to allow it to be removed, http://www.showerdoc.com/shower-spares/trevi/idl-a953957nu11-temperature-adjustment-carrier mark the position it was in when you removed it so you can reposition it in the same position when rebuilding the valve/
Then remove the gear carrier http://www.showerdoc.com/shower-spares/trevi/mixer-showers/idl-a923711-ctv-volume-control-handle-geared-carrier and this should let you in to the temperature cartridge http://www.showerdoc.com/shower-spares/trevi/mixer-showers/idl-s960134nu-trevi-thermostatic--cartridge-to-replace-a963564nu
Answered 11 years ago by The Shower Doctor
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Trevi Ctv Thermostatic Valve Exposed Shower Valve
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