Dripping Shower.

[Atheist]

I have a thermostatic bar shower mixer supplied by hot (Vaillant Combi) and cold pipework. One end of the bar has the thermo temp control knob and the other has the flow control knob.
The shower head drips slowly. If I lay the shower head in the bath overnight, having loosened the flex connector to allow the hose to empty, then retightened the connector, the head still shows that water is coming through overnight. There is not enough flow to cause the boiler to fire to heat the hot water.
I presume that the problem would be with the flow control cartridge (not the thermo cartridge), but a new one would cost about £60. Before I consider replacing the cartridge, would it be worth taking it out to check for dirt, then replacing?
Or does anyone have any other ideas?

[bookbinder]

Try removing the shower head and fitting a new washer between the head and the hose.

[Spicerack]

How kind. You've ignored your own problem to help someone else.
I can't answer but I can bump this back up. Viola.

[Atheist]

Thanks, bookbinder.
I don't see that that could make any difference. If water is coming through, then the state of the hose connector washer doesn't matter, does it? There's no leakage at the hose connector end. It seems to me that the flow cartridge must be letting water through. BTW the mixer is three years old.

[Atheist]

Spice, I don't understand your answer! :-)

[bookbinder]

Neither do I, Atheist! You might like to have a look at this:
https://my-plumber.co.uk/blog/leaking-shower/

[Spicerack]

Your question was about to fall off the board. So I bumped it back up for you. Bookbinder had already done it.

[Atheist]

Thanks, book....
I don't think that really helps. :-)

[Atheist]

Thanks, Spice. (Does this count as a bump up?)

[bookbinder]

Oh, dear! I am trying to help! But I'm not really helping at all! Sorry!

[melv16]

Take out the cartridge and give it a clean. Are you in a hard water area?

[bhg481]

I think cleaning the flow-control is a good starting point. Like melv, I suspect hard water problems.

[Atheist]

book..., I'm grateful for any suggestions.
melv..., yes, hard water. I suppose the cartridge will have ceramic discs. Do I just look at it and do whatever appears to be sensible?

[melv16]

I'm sure they'll be a video on YouTube to show you the way.

[The Builder]

Hello Atheist. I very much doubt that you will be able to see anything useful by inspecting the cartridge. Even if you could dismantle it, there wouldn't be very much to see.
3 years for a good quality unit isn't really long enough for seals etc to perish or otherwise give problems.
I suspect the old tiny bit of grit. It really doesn't take much at all .

The annoying thing is that these things often sort themselves out after a few more opening/shutting cycles.
It happened with my own shower. A good quality MIRA unit.
I let it drip for a few more days, then just as I was about to get a replacement.............. it stopped on its own.

It obviously flushed itself out. Modern valves can be quite sensitive to even the smallest piece of grit.
So there. No help at all then :o(

[Atheist]

Thanks, Builder. It's been dripping for a few months and, although the amount of wasted water doesn't amount to a hill of beans, Mrs A finds it intensely annoying and all my fault!
I think I'll whip out the cartridge and scrub it and give it a vinegar soak.
I'll be back when I have some feedback to post.