Thermostatic shower issues.

[Burnerman]

An unusual question maybe.....if the water supplied to a thermostatic shower is too hot, can it override the thermostatic valve?
My immersion heater thermostat failed and the water heated up much too hot - I realised and stopped it from boiling but I reckon the temperature was in the region of 75 deg at a guess.
Trying to use the shower - Mira Silver Exposed, fed at 0.3 bar - and it just wouldn't go cool enough to use.
I'll try again once the water has cooled down, but any comments greatly appreciated!
Cheers
John

 

[terryplumb]

The hot water temperature may have been much higher than you think ,and way above that which the valve can cope with .It really should close down totally to prevent you from being scalded. I suspect your shower valve may be duff

 

[Burnerman]

Thanks Terry!
The shower is now adjustable from bloody scalding down to just hot.....no way can I get it cold and for sure it doesn’t show any signs of shutting down.
I’ll check the filters tomorrow and if they are ok its a new cartridge at £130
Cheers for your input
John