Viega 20878 ProPress tee Smart Connect technology Copper, 2-1/2'' x 2-1/2'' x 2''

The 20878 is a reducing tee with two press ends and one threaded branch: 2-1/2 inch press run, 2-1/2 inch press run, and a 2 inch female pipe thread outlet. Viega calls the ends P1 x P2 x FPT. So you press the two 2-1/2 inch copper run connections and thread into the 2 inch branch, which is where you'd land a valve, a gauge assembly, or a transition to threaded pipe.

Copper. It's a copper ProPress fitting, so it's meant for copper tube systems rather than as a general-purpose bronze threaded fitting. Keep that in mind on the FPT branch: whatever you thread into it should be compatible with copper in your water chemistry, and you'll want the usual dielectric precautions if you're going to steel.

The FPT branch on the 20878 exists for the places where you can't press: a threaded ball valve, a backflow assembly, a gauge or sensor tapping, a transition to threaded black iron or a pump connection. If every connection in the run is copper tube, an all-press 2-1/2 x 2-1/2 x 2 tee is simpler and removes a thread joint you have to dope and torque. Pick the FPT version only when the branch genuinely terminates in a male thread.

Smart Connect is Viega's unpressed-joint detection feature. During pressure testing, a connection that was missed leaks noticeably so you find it before the walls close, instead of discovering it after startup. On a 2-1/2 inch fitting like the 20878 that matters more than usual, because large-diameter joints are the ones that get skipped on a long run and the ones that do the most damage when they let go.

Viega part number 20878. It's the copper ProPress tee in 2-1/2 x 2-1/2 x 2 with two press run ends and a female threaded 2 inch branch, made in Germany. Quote that number and the P1 x P2 x FPT configuration so nobody substitutes the all-press version.

ProPress fittings ship with the sealing element already seated in each press socket, so there's nothing to assemble before install. Your job at the joint is the usual sequence: cut square, deburr, mark insertion depth, make sure the tube is fully home, then press. The 2 inch threaded branch takes thread sealant as normal.