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Bronze ProPress dielectric union, press-to-FNPT, 1-1/4 inch connections, EPDM O-ring

Viega

Viega 79170 ProPress di-electric union trap 1-1/4" x 1-1/4

SKU CH-3DX0-7P8WF MPN 79170

Bronze di-electric union joins 1-1/4 in press-fit to FNPT for potable water, rated 200 psi and 250 °F

  • TypeDrain Components
  • MaterialHAWA
  • Prevents galvanic corrosion with bronze dielectric construction
  • Press-fit copper connection installs without soldering
  • FNPT threaded end joins standard 1-1/4" pipe
  • EPDM O-ring seals up to 200 psi pressure
  • Rated for 250°F maximum operating temperature

Di-electric Union for Potable Water

The Viega 79170 ProPress di-electric union connects copper tubing to female NPT threads in potable water systems. Its bronze body and EPDM O-ring provide corrosion resistance between dissimilar metals. The press-fit connection on side A eliminates the need for soldering or threading during installation. Suitable for residential and commercial plumbing applications.

Press-Fit Connection on Copper Side

Side A accepts 1-1/4 inch copper tube size via a ProPress crimp fitting, while side B offers a 1-1/4 inch FNPT thread. This specific interface combination determines compatibility with existing pipework and transition requirements. The di-electric design prevents galvanic corrosion at the joint. No other connection types are featured on this fitting.

Rated for 200 psi and 250 Degrees F

The union handles maximum operating pressures of 200 psi and temperatures up to 250 degrees Fahrenheit. It comfortably serves standard hot and cold water distribution lines within these limits. Systems exceeding either pressure or temperature ratings require alternative components. Overall length measures 2 11/16 inches for space planning.

Highlights

  • Prevents galvanic corrosion with bronze dielectric construction
  • Press-fit copper connection installs without soldering
  • FNPT threaded end joins standard 1-1/4" pipe
  • EPDM O-ring seals up to 200 psi pressure
  • Rated for 250°F maximum operating temperature

Specifications

TypeDrain Components
MaterialHAWA
BrandViega
Model79170

Questions about this item

How does the 200 psi pressure rating hold up in a real installation?

The fitting is rated for a maximum operating pressure of 200 psi, so it will handle typical potable-water service pressures without leaking when the press connection is made correctly.

What does the press-fit connection on one side and FNPT on the other actually limit?

Side A uses a press-fit connection for 1-1/4 in copper tube while Side B is a 1-1/4 in FNPT thread, so the joint type is fixed by the fitting and cannot be changed to sweat or push-fit.

Will the 2 11/16 in overall length fit inside a standard stud bay?

At 2 11/16 in long, the union is compact enough for most residential stud cavities, but verify the exact clearance around adjacent fittings before pressing.

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