Viega ProPress Unions

Viega ProPress unions let plumbers make a serviceable, disconnectable joint in a copper piping system using the same press connection method as the rest of a ProPress installation, no soldering required. The line includes several union types, including press by female pipe thread, press by male pipe thread, press by press, and dielectric unions for transitioning between copper and steel piping. Viega's dielectric union, for example, is built from silicium bronze with an EPDM sealing element and covers sizes from a half inch up to two inches. Because the union closes with Smart Connect Technology, an unpressed connection shows up immediately during system testing rather than after the wall or ceiling is closed up. For service points, equipment connections, or any joint that might need to come apart later, a ProPress union avoids cutting into finished pipe to make the repair.

Subcategories

• Press by Thread Unions: Press by female pipe thread and press by male pipe thread unions give a press connection on one side and a threaded connection on the other, which is useful where the joint needs to mate with threaded equipment or valves. Zero Lead compliance applies across the ProPress union line, making these suitable for potable water applications. Smart Connect Technology also carries over to these fittings, flagging an unpressed joint during pressure testing. Plumbers commonly use these unions at equipment connections where a threaded shutoff or gauge needs to attach.
• Press by Press Unions: Press by press unions connect two pressed copper runs while still allowing the joint to be taken apart later without cutting the pipe. Plumbers place them at access points, meter connections, or anywhere a future service disconnect is likely. These unions share the same Zero Lead compliance and Smart Connect Technology as the rest of the ProPress union line. Placing a union at planned service points during rough-in saves time on future repairs.
• Dielectric Unions: Dielectric unions transition between copper and steel piping while preventing the galvanic corrosion that happens when dissimilar metals contact directly. Viega's dielectric union is built from silicium bronze with an EPDM flat gasket and sealing element, and it's available in sizes from a half inch up to two inches, ranging from 0.815 to 2.865 pounds depending on size. These unions are Zero Lead compliant, matching the rest of the ProPress union line. Anywhere copper meets steel or galvanized pipe, a dielectric union is the standard way to make that transition safely.

Buying Guide

Deciding which union to use starts with what's on the other side of the joint. A straight copper-to-copper disconnect point calls for a press by press union, while a connection to threaded equipment, valves, or gauges needs a press by thread configuration instead. Anywhere copper transitions to steel or galvanized pipe, a dielectric union is the right call to prevent galvanic corrosion between the two metals.

Sizing matters next. Viega ProPress Unions cover a range from a half inch up to two inches, so confirming the pipe size on both sides of the transition avoids ordering the wrong union. For potable water work, Zero Lead compliance applies across the union line, which keeps the material selection simple regardless of which union type gets used.

Planning ahead for service access is worth considering during rough-in, not just during a repair. Placing a union at equipment connections, meter locations, or other points likely to need future disconnection saves time down the road, since a pressed joint without a union has to be cut out to service. Smart Connect Technology flags any unpressed joint during testing, so confirming every union shows a pressed connection before closing up walls or ceilings avoids a callback later.

Frequently Asked Questions

What's the difference between a press union and a standard press fitting?

A union allows the joint to be taken apart later without cutting the pipe, while a standard press fitting makes a permanent connection. Plumbers place unions at service points, equipment connections, or anywhere future access is likely.

Are ProPress unions safe for potable water?

Yes, the ProPress union line is Zero Lead compliant, which applies across the press by thread, press by press, and dielectric union types. Zero Lead compliance covers standard potable water applications across the line.

When do I need a dielectric union instead of a standard union?

Use a dielectric union anywhere copper piping transitions directly to steel or galvanized pipe, since dissimilar metals in contact can cause galvanic corrosion. Viega's dielectric union is built from silicium bronze with an EPDM sealing element to manage that transition safely.

What sizes do Viega ProPress unions come in?

Sizes run from a half inch up to two inches across the union line, covering most residential and light commercial copper piping runs. Confirming the pipe size on both sides of the joint before ordering avoids a mismatch.

How do I know if a ProPress union joint was pressed correctly?

Smart Connect Technology is built into Viega's press fittings and unions, which causes an unpressed joint to leak visibly during pressure testing rather than passing inspection. Catching a missed connection this way happens before the wall or ceiling gets closed up.