Do slotted isolating valves fail

[opps]

I have been trying to troubleshoot my mum's bath/shower valve.

Crosswater 3 way thermostatic valve- 90 mins to run a bath

Hi all, my mum has the same crosswater thermostatic valve that I have. Mine is mains water pressure, hers is on a gravity fed system. Over time, the pressure on hers has been dropping off (substantially). It looks like the following (but with slightly different tap heads)...

www.diynot.com

Today, I used a slotted screwdriver to close the two isolating valves.

I pulled the thermostatic cartridge out and noticed that the hot water isolating valve was still letting water past (running out of the housing for the the cartridge). Out of interest, I opened the isolating valve fully, and then noticed that the amount of water coming out of the housing was pretty much exactly the same.

Can those isolating valves fail in a frozen semi open state?

I am used to them spitting water out of the front and not fully closing, but I have never encountered one that turns but doesn't open fully.

I will add that I have thus far been unable to remove the filter for the hot water on the bath/shower valve, but given that the hot water isolating valve does not close leads me to assume that it is at fault

 

[terryplumb]

Yes they fail. Pretty much everything that the human race has ever invented can fail.

 

[Jurassicspark]

They are not common to fail but sometimes they do. Mostly gate valves IMO fail like this. Every plumber knows that.


Do you know how long that isolation valve has been living for?

 

[Deluks]

I've replaced a few of mine with a ball lever valve. Costs ten times as much, but more reliable and saves faffing around looking for a screwdriver.

 

[opps]

They are not common to fail but sometimes they do. Mostly gate valves IMO fail like this. Every plumber knows that.


Do you know how long that isolation valve has been living for?

Not sure about the age. In excess of 10 years. Since installation it had only been turned off once previously (possibly 4 years ago).

 

[footprints]

I have got to the stage I put a bit of silicone grease in them and operate a few time before I install them!

 

[opps]

I've replaced a few of mine with a ball lever valve. Costs ten times as much, but more reliable and saves faffing around looking for a screwdriver.

These days I only use the Pegler lever valves.

I had a Toolstation lever valve that snapped 3 years down the line. It caused £5k of damage.

I posted images here and others pointed to the granular structure of the metal in the break.

 

[Jurassicspark]

been turned of once previously (possibly 4 years ago).

There you go mate!

 

[Nige F]

Pegler lever valves as opps says

 

[pcaouolte]

Is it a good idea to operate these little slotted isolating valves regularly to keep them working or does that just make them more likely to leak?

 

[Jurassicspark]

Is it a good idea to operate these little slotted isolating valves regularly to keep them working or does that just make them more likely to leak?

Opening them regularly does reduce the chances of them leaking especially gate valves.

Gate valves are most likely not to be turned in years that's why they leak when opened for the first time in 10 years.