Shower gradually stops delivering water

[Unmesh]

We're having a weird intermittent problem with our Kohler shower.

The shower is a Kohler Finial with a Rite-Temp 1/2" pressure-balancing valve K-304-KS-NA. We shower with the handle in the full on position. At times, the shower output will begin to slow down after a few minutes almost to a stop. The "fix" is to turn the handle to a full off and then to again bring it back to a full on and it starts working again though sometimes it will again slow down to a stop in less than a minute and you have to repeat the off-on movement with the handle.

The other thing to mention is that if someone else uses the shower after a few minutes, they don't see the problem.

And by intermittent, I mean every other week or so.

We had a plumber in but the shower was on its best behavior during his visit so had only our description to go by. He replaced the the mixer cap and the pressure balancing unit (PBU) but the problem resumed a few days later.

Any suggestions?

Thanks

 

[WorthFlorida]

Is this with a mix of hot and cold water running, not full hot or full cold? Have you removed the shower head? When it happens, just remove the shower head without touching the valve. You may want to keep an adjustable wrench or pliers next to the shower.

 

[Sponsor]

 

[John Gayewski]

Sounds like crud in the piping that passes.

 

[Unmesh]

@WorthFlorida

I will try and remember to do that and report back.

@John Gayewski

Sounds intriguing. Where does the crud pass to? Is there a remedy for a DIYer like myself or that I can pass along to a plumber?

Thanks