Shower mix tap expanding and jamming

Gazelle1985

We have a fairly standard shower mixer tap – one tap to turn on and adjust water flow, and the other tap adjusts temperate. Before turning it on, the water temperature tap is adjustable (if a little stiff). However, once the shower is on, it’s only possible to turn it one way (to make it hotter). It gets jammed, and it’s impossible to make the shower any colder.

I can only assume that the valve expands as hot water passes through it, which causes it to become jammed. Is there any solution to this other than replacing the valves and taps?

jk0

Try WD40, but sounds like you need a new one.

Rodders53

Avoid WD40. The whole tap / thermostatic head probably needs stripping down. Limescale and other stuff clearing out, filters cleaned and all reassembled.

A smear of silicon grease to lubricate bits probably won't harm during the reassembly.

Carrot007

Mine does this too!


And as above I think it's mostly limescale.


A good descaling/clean does wonders to it for me. And is easier it you take it apart first!

Gazelle1985

Thank you. We've actually tried taking it all apart and descaling and WD40 already, and both helped temporarily, but then quickly went back to being stiff when the hot water is on.

I feel like it must be something to do with the valves expanding from the heat but would replacing the taps actually help that?