Shower Not Getting Hot (gets warm, but unlike the taps in the room)

[hodgevaldo]

Ive troubleshooted it being the anti scold needs adjusting, however I have taken everything off the faucet to as much as I can.
I have no idea how I get past where ive got to, any ideas?

 

[Ric2013]

Is that even a thermostatic mixer, or is there a separate anti-scald thermostatic device? How hot is the hot pipe feeding the shower mixer? [EDIT- probably me barking up the wrong tree, though always good to check]

Some thermostatic mixers (most of them actually) will always mix in a significant amount of cold water and are unable to give water hotter than 10 degrees lower than the temperature of the unmixed hot water. The best one I installed was a Grohe (expensive) and it can deliver water to within 2 degrees. Might this be the problem?

 

[hodgevaldo]

Is that even a thermostatic mixer, or is there a separate anti-scald thermostatic device? How hot is the hot pipe feeding the shower mixer? [EDIT- probably me barking up the wrong tree, though always good to check]

Some thermostatic mixers (most of them actually) will always mix in a significant amount of cold water and are unable to give water hotter than 10 degrees lower than the temperature of the unmixed hot water. The best one I installed was a Grohe (expensive) and it can deliver water to within 2 degrees. Might this be the problem?

The hot water pipe feeding into the mixer is baking hot.
When turning the valve to get it warm, you have to turn it a number of times for it to reach the warm temp, and then you cant go any further.

 

[Ric2013]

The hot water pipe feeding into the mixer is baking hot.
When turning the valve to get it warm, you have to turn it a number of times for it to reach the warm temp, and then you cant go any further.

Good. That rules out an external blending valve.

 

[hodgevaldo]

Good. That rules out an external blending valve.

so where do you think the issue could be?

 

[Ric2013]

Well, I think the issue may be that that there's a maximum temperature limiter that is set too low (your original idea), or that 'warm' to 'baking hot' is an inherent feature of the type of thermostatic valve you have. Or that the thermostatic cartridge is seized (limescale?) or otherwise faulty.

I suppose you could test my theory by measuring outlet temperature accurately and then varying the inlet hot water temperature at the boiler or cylinder. If the outlet temperature keeps a fairly precise number of degrees below the inlet temperature, then it's a part of the valve design and the only solution would be to increase the inlet temperature to a point that allows a decent output temperature.

 

[hodgevaldo]

Hi, so I managed to remove the tap part of the shower valve. Now I thought I was going to remove some sort of catridge which could be replace, but this is totally different.
Could someone be able to explain why the hot water is not coming out very hot with this type of system.

There are 2 picture, one of the tap part which shows the fittings, the other is the inside of the shower valve,

 

[Ric2013]

I'd love to help, but find it hard to understand how something works without having it in front of me and being able to 'play' with it. I can't even make out if that's a thermostatic shower or not, I'm afraid.