No hot water to bath/shower mixer tap

[simonslade]

I'm getting hot water to both the kitchen sink and the bathroom basin but not to the bath/shower mixer tap. The bathroom is in the extension beyond the kitchen - typical Vicky terrace layout.

When I turn on the hot taps for either the kitchen or bathroom sink/basin the Ariston combi fires up to 50 degrees and the outlet pipe from the boiler gets hot. When I just turn on the bath mixer tap it only fires up to 30 degrees and the outlet pipe from the boiler stays cold. If I run the basin taps to get the boiler to fire up to 50 and then turn on the bath tap t drops to 30

I'm totally confused!

[The Builder]

How would you like a long shot Simon? ........... since only the bath mixer is causing the problem ............. I can only think that the mixer body is faulty.
MAYBE, the Cold mains water is crossing the valve and getting into the Hot from the Combi.
I've really no idea what would happen if it did, but I guess it could "push" the Hot back into the Combi, and tell the pressure valve/regulator to switch off ........ just like turning off a tap.
???

[simonslade]

Thanks, I'll check/replace out the mixer tap assemly

[Rdm181]

Hi, the water in shower is hot (in the C/coldest setting) or boiling hot (in the H setting). Would you be able to tell me what needs fixing? Many thanks!

[Rdm181]

Hi there, the water in the shower goes from hot (in the C/coldest setting) to boiling hot (in the H setting). There is not cold water. Would you be able to tell me what needs fixing? Many thanks!