Delta Tub/Shower Rough Valve - What is This Part?

[mnocket]

Getting ready to replace my old tub/shower valve with a Delta R10000 rough-in valve body. This part (pictured) came in the box and is not mentioned in the instructions and I can't see any use for it. Anyone know what it's for?

 

[Marlinman]

It is a test plug.

Pressure Test Plug - Hot / Cold RP46079 | Delta Faucet

Pressure Test Plug - Hot / Cold

www.deltafaucet.com

 

[Sponsor]

 

[Tuttles Revenge]

Its function is to prevent hot and cold from mixing in the valve and being sent to other fixtures. If you install the rough in valve now and don't have the cartridge to install, you would install that plug until you install the cartridge.

 

[LLigetfa]

Its function is to prevent hot and cold from mixing in the valve and being sent to other fixtures.

Winner winner, chicken dinner.
The test cap alone does not prevent crossover.

 

[JLSinBpt]

I realize this thread is old, but I'm hoping someone can please clarify this for me...

I understand WHERE this goes and WHAT it does (i.e. prevent hot and cold from mixing in the valve during a pressure test). Can someone please explain WHY that is important? If I'm performing a pressure test when the pipes are exposed, who cares if the hot & cold are mixing in the valve?

Thanks!

 

[AndyB7]

.

 

[AndyB7]

I realize this thread is old, but I'm hoping someone can please clarify this for me...

I understand WHERE this goes and WHAT it does (i.e. prevent hot and cold from mixing in the valve during a pressure test). Can someone please explain WHY that is important? If I'm performing a pressure test when the pipes are exposed, who cares if the hot & cold are mixing in the valve?

Thanks!

Not a plumber but I just found out why this is useful. The hot/cold crossover is irrelevant to the shower you're installing testing but can cause other 'live' fixtures nearby to deliver a hot/cold mix when only hot OR cold is required. I'm about to order the part you pictured.