Hot water runs when tub faucet off

[DigitalAlien]

Hey all!
I have a new D210000BT Tub filler valve shown here

For some reason when the hot water side is shut off some water still runs out of the faucet. Not just drips out but runs out like it is not closed all the way. So I thought, "New Cartridge!" So as a temp fix so I could turn on my hot water I placed a penny in rubber fitting on the bottom of the cartridge (perfectly fit in the place where the metal washer goes.

<--Penny went in the orange fitting.

This stopped the flow of water which, so I am thinking, validates that it is in fact a bad cartridge.

So, now I am on my 3rd cartridge and still... same thing.
I hate to have to replace the entire valve, but... seems like the only option at this point. I am confused though as to why, if it is a valve issue, the water would not still run with the penny in? And also what in the valve could be messed up to cause this? My understanding it that if the water is being held back by the penny then the only thing letting the water through without the penny would be the cartridge. (meaning it would HAVE to be the cartridge) I find it unlikely I have 3 bad cartridges though.

Also wondering if water pressure could play a part in this?

Thanks in advance for any thoughts or suggestions!

 

[DIYorBust]

How do you know it's not the other cartridge?

 

[Sponsor]

 

[DigitalAlien]

Sorry, I may be confused on your question. I have tried 3 cartridges though and they all do the same thing. What other cartridge are you referring too?

 

[DIYorBust]

Sorry, I may be confused on your question. I have tried 3 cartridges though and they all do the same thing. What other cartridge are you referring too?

The cold side.

 

[DigitalAlien]

Oh, well it's hot water leaking out. And also because when I put the penny in the cartridge on the hot side it doesn't leak.

 

[Jadnashua]

You may have a defective seat where the valve seal mates up to stop the flow. Depending exactly on the model and design, that may be replaceable, repairable, but may mean you have to replace the whole valve.

When you take the valve stem out and look at the bottom, where the seal goes, is that nice and smooth?

Is it nice and smooth where the O-ring ends up near the top?

Try opening the valve prior to screwing it in.

Are you sure you've tightened it properly? Sometimes, it can make a big difference if you apply some silicone plumber's grease to the O-ring prior to inserting the parts...that can help the O-ring to seat properly. They sometimes come dry, and then they can distort as you try to tighten things up, or, not slide properly into position, and thus, not sealing. If the original O-ring was damaged or worn out, all it might have needed was a new one.

I had one cartridge that just wouldn't push in all the way properly until I added some grease, then it popped right into position and worked as needed.

 

[DIYorBust]

But why would the penny outperform the o-ring if the seat is rough?

 

[Jadnashua]

The seat is probably okay, but the cartridge is probably not seated properly. That's where some plumber's grease on the O-ring can help things snap into place. It's hard to say unless you're there and can look at things.