Thermostatic shower problems - help appreciated

[Isabella1662]

This is a thermostatic shower fed cold from mains and hot from combi bolier. When it was installed it worked fine. Now it is either boiling hot or freezing cold (when boiler shuts off). It is impossible to get warm, mixed water.

- Can limescale affect these valves? if so are they easy to clean?
- Can they develop faults? and if so can the valves be purchased separately of do I have to install a new shower.

 

[kevplumb]

Can limescale affect these valves?

yes

if so are they easy to clean?

depends on the valve

- Can they develop faults?.

yes

can the valves be purchased separately

usually

make of shower would help