Thermostatic Shower Cartridge

[Diggory]

Hi there - I’ve been having some trouble with a mixer shower; no hot water.
The shower has not been used for a while - I’ve removed the thermo-cartridge and cleaned out the gritty bits.
I’ve soaked cartridge for couple of hours in a citric acid solution.
I’m now getting hot through but as I adjust the temperature it thumps (like a single water hammer) as the hot comes in.
I’m guessing it’s now moving but sticking - is there anyway I can free it off ?

I believe it’s a Trevi 300 shower.

Thanks in advance D

 

[Diggory]

I gave it another 2hrs soak - it’s marginally improved but still ‘thumping’. If I wind it (temp dial) all the way in it gets too hot, then as I back it off, at about half way, it goes ‘thump’ - the temperature drops (too cold) and the water flow notably increases.

I’m mindful that when the dial is fully assembled the rotation of movement will be quite restricted (even if I slide the red stop out of way) based on the 40degC factory set calibration. I’m getting hot flow only by going beyond the region of restricted rotation.

As I mentioned in the previous post, the shower has been unused for a good while; and I’ve assumed this was the issue. The shower was previously running from a vented boiler, loft tank and monsoon shower pump. I’ve since had a new combo-boiler fitted. Might this be causing my problem ?

 

[denso13]

Might this be causing my problem ?

Probably just worn out, new cartridge or shower valve should fix it.

 

[Diggory]

Thanks @denso13 (again).

True enough - it could be shot.

I did wonder that I’m getting hot through it now only because I can rotate it further (with dial dismantled).
And that this might be to do with water pressure / combi boiler.

Best D