Plumbing riddle

[waterboy]

I know only enough about plumbing to get me in trouble, but am stumped by a recent issue in my shower.

Shower has a Kohler single handle mixer control. When the toilet in this same bathroom is flushed the shower head will leak a small amount of water while the toilet tank fills (probably about one or two cups). Once the tank is filled and water shuts off to the toilet, the shower no longer leaks, not even a drop. 

Any flushing of other toilets or running of any other faucet in the home does not product the same result of the shower leaking. 

On a whim, I went ahead and bled the water system to the home thinking a air pocket could somehow create this problem. I don't know that I did the blead correctly, but the problem was the exact same after. 

I am stumped. anyone have any ideas?

[crokett™]

My sister had that problem on her shower after upgrading the fixtures after a pipe burst and flooded her house, but I digress. It was diagnosed to a faulty anti-scald device in the mixing valve letting water by during lower pressure situations when toilet was filling. This was a couple years ago but I think they figured out by accident. they just happened to try flushing with the hot water off and it didn't do it with the hot water supply turned off.

so I think that's what I'd try. turn off the hot water supply to the shower if you can, if you can't turn it off at the water heater and open taps to get the hot water pressure out, then leave it off and try flushing again.

my only other guess is water hammer when the toilet fill valve closes but the shower head should leak after it stops filling and the valve closes, not during.

[Roly]

I know only enough about plumbing to get me in trouble, but am stumped by a recent issue in my shower.

Shower has a Kohler single handle mixer control. When the toilet in this same bathroom is flushed the shower head will leak a small amount of water while the toilet tank fills (probably about one or two cups). Once the tank is filled and water shuts off to the toilet, the shower no longer leaks, not even a drop. 

Any flushing of other toilets or running of any other faucet in the home does not product the same result of the shower leaking. 

On a whim, I went ahead and bled the water system to the home thinking a air pocket could somehow create this problem. I don't know that I did the blead correctly, but the problem was the exact same after. 

I am stumped. anyone have any ideas?

 Suggest calling Kohler.  First go online and see if you can figure out the model #.    Probably the pressure balance type and the loss of pressure on the cold side my allow it to drip if the springs are weak.   My have to replace cartridge if they don't have a rebuild kit.   Roly

[waterboy]

 Suggest calling Kohler.  First go online and see if you can figure out the model #.    Probably the pressure balance type and the loss of pressure on the cold side my allow it to drip if the springs are weak.   My have to replace cartridge if they don't have a rebuild kit.   Roly

Thank you for the ideas. 

Sorry, I did leave out two details. The mixer was replaced about 6 months ago, previous one was leaking. Water heater replaced in June. Problem did not exhibit then. In August water heater exhibited some strange behavior, and the plumber replaced burner element under warranty. It was within a week or two after that problem with shower head leaking began. 

So maybe I will try the bleed again, this time ensuring I fully drain the water heater. I did not do that last time.

[daddo]

Cheap Plumber; "Stop flushing the turlet".

Whatever Plumber; "Your thingamajig ain't workin' right".

Best Plumber; "The mixer needs replacing".

[Phil Thien]

The water coming out of the shower isn't yellow or brown, is it?

[waterboy]

The water coming out of the shower isn't yellow or brown, is it?

LOL. 

Thankfully no.

[Bob10]

I know only enough about plumbing to get me in trouble, but am stumped by a recent issue in my shower.

Shower has a Kohler single handle mixer control. When the toilet in this same bathroom is flushed the shower head will leak a small amount of water while the toilet tank fills (probably about one or two cups). Once the tank is filled and water shuts off to the toilet, the shower no longer leaks, not even a drop. 

Any flushing of other toilets or running of any other faucet in the home does not product the same result of the shower leaking. 

On a whim, I went ahead and bled the water system to the home thinking a air pocket could somehow create this problem. I don't know that I did the blead correctly, but the problem was the exact same after. 

I am stumped. anyone have any ideas?

your house is haunted!!!

[crokett™]

n August water heater exhibited some strange behavior, and the plumber replaced burner element under warranty. It was within a week or two after that problem with shower head leaking began. 

Plumbing is a system.  I troubleshoot other types of systems for a living.  It is very very rare for there to be two coincidences in a system where 2 things go sproing around the same time and they aren't related to each other.  I'm going to say that either burner replacement or the water heater strange behavior somehow caused a problem on the mixing valve.

[MstrCarpenter]

Plumbing is a system.  I troubleshoot other types of systems for a living.  It is very very rare for there to be two coincidences in a system where 2 things go sproing around the same time and they aren't related to each other.  I'm going to say that either burner replacement or the water heater strange behavior somehow caused a problem on the mixing valve.

Disturbing the pipes will dislodge debris that's accumulated on them; from the inside too. I think that's what you'll find in the valve. If it's from people hanging on to it for balance, it's time for a grab bar.