Leaking shower arm

[KristenJensen]

I noticed a drip from my Delta shower trim kit head, so I removed it down to the shower arm to inspect, isolate, and clean. The drip was coming from the shower arm pipe itself and not some malfunction of the trim kit.

I can see behind the shower (mechanical room) and there is no leak from the rear. The shower has two distinct handles: one turns the water on and the other controls the temperature.

I noticed that when I turn the mixing valve temperature control from hot to cold, the drip increases in frequency to about 2 drips a second, otherwise it is 1 drip every 2 seconds. Since (I think) I've ruled out a cracked shower arm or drop ear, and there is no leak behind the wall, my theory is that something in the mixing valve (maybe the cartridge) is no longer stopping the water from traveling up the pipe even when fully turned off.

I'd like to know if this is something common and if the typical fix is replacing a cartridge from the mixing control mechanism. Trim kit is ~6 years old. Thank you all in advance for your consideration. pictures attached.

 

[Sylvan]

Take the shower apart and check for debris AFTER you shut the supply valves

 

[Sponsor]

 

[KristenJensen]

Take the shower apart and check for debris AFTER you shut the supply valves

Thanks for the response, Sylvan. But I'm a bit confused.

All plumbing tubes are hollow. I have CPVC that travels from the mixing valve to the metal drop ear, then to the metal shower arm. Why would it matter if there is debris in the CPVC/shower arm or not? Why would debris allow water to drip out of a "naked" shower arm coming out of the wall? Why is water (pressurized) traveling up to the shower arm when the mixing valve is turned all the way off?

Thank you, sir. I'm hoping to learn from others,

 

[John Gayewski]

Generally when this happens it's because someone installed the rough valve upside down.

Edit. I thought you were talking about a drip when bathing. Yes you need a new cartridge if this is just a plain drip when the valve is supposed to be off.

 

[GReynolds929]

The leak is not from the pipes. It is from the volume control valve not shutting water all the way off. New cartridge is needed.

 

[KristenJensen]

Just want to tell future readers that I bought a generic shower cartridge kit from Amazon (~$60) and installed it. It worked. No more leaks.

I did see videos that recommended just replacing the rubber washers (behind the cartridge) for $5.00 and reinstalling the same cartridge, but I didn't go that route.