Can't adjust thermostatic control

[Slinky5885]

My bath water is lukewarm, so I removed the panel and tried to adjust the preset temperature, but it won't budge when I try and turn it anticlockwise? It will only go clockwise to the cooler side? The valve is a Gummers Bristan MT503

 

[ianmcd]

It is not adjustable it is pre-set

 

[Slinky5885]

So there's nothing I can do at all to make it hotter?

 

[ianmcd]

yes find out why it is not working correctly, could be a locked filter or non return valve

 

[Slinky5885]

I see... And how would a complete moron in the plumbing field go about checking these things? I'm at a loss here haha

 

[Alec_t]

It is not adjustable it is pre-set

Why the red and blue indicators if the preset temperature isn't adjustable?

 

[ianmcd]

Why the red and blue indicators if the preset temperature isn't adjustable?

they simply indicate what side each pipe is connected to

 

[Alec_t]

Ah, thanks. Looks like an Allen key would fit the central hole. Is it just for assembling the valve rather than adjustmnt?