Nibco 733-4 Fitting Union C x ...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$168.90
Nibco 733-4 Fitting Union C x M - Cast

Nibco 733-4 Fitting Union C x M - Cast

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Model: B260350

In Stock (leaves warehouse same day if ordered before 3pm ET)

$168.90
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The union features a solder cup and male NPT threads. The fitting is used to allow repair to the line without damage as well as adapt from a solder connection to a threaded connection. Please refer to NIBCO technical data sheets and catalogs for engineering and installation information. In addition to its inherent qualities of beauty, durability and low maintenance, copper's reusability makes it an ideal application in sustainable projects. NIBCO® copper fittings are manufactured in an ISO 9001 certified facility, and backed by a 50-year limited warranty. Because of its longstanding reputation for innovation and precision in design and manufacturing, NIBCO is the preferred brand in the industry.

  • Dezincification resistant
  • Use in U.S. drinking water applications is prohibited after January 3, 2014
  • ASTM B584 Alloy C84400
  • Material and workmanship per ASME B16.18

Copper Fittings Installation Instructions

Manufacturer Resources

Product Specs

All Basic Material:
Bronze
Classification:
Solder Pressure Unions
End Connection:
Threaded
Metal End Connection Type:
C x M (NPT)
Product Group:
Fitting
Product Type:
Solder Pressure Unions
System Use:
Commercial Plumbing, Fire Protection, Heating, HVAC, Industrial, Irrigation, Residential Plumbing
Product Subgroup:
Union
Department:
Plumbing

Nibco B260350 – Frequently Asked Questions

1) What kind of connections does the Nibco 733-4 union have on each end?
One end is a solder cup that sweats onto copper tube, the other is male NPT pipe thread. That C x M arrangement lets you transition from a soldered copper run to a threaded connection, and the union nut lets you break the joint later without cutting the line.
2) Can I use the Nibco 733-4 bronze union on potable water in the US?
No. Nibco states use in U.S. drinking water applications is prohibited after January 3, 2014. It is a cast bronze union to ASTM B584 Alloy C84400, which is not a lead-free alloy for potable service. Keep it to non-potable work such as heating, HVAC, fire protection, industrial and irrigation lines, and pick a lead-free union for domestic water.
3) What pipe sizes does the Nibco 733-4 C x M union come in?
Ten sizes: 1/4, 3/8, 1/2, 1/2 x 3/4, 3/4, 1, 1-1/4, 1-1/2, 2 and 2-1/2 inch. The 1/2 x 3/4 is the reducing version, so you can sweat 1/2 inch copper and thread into a 3/4 inch connection without a separate bushing.
4) Why use a union here instead of a plain copper male adapter?
A male adapter is a permanent joint, so servicing the line means cutting it. The 733-4 has a union nut in the middle, so you can break the connection at a pump, valve, water heater or control and put it back without damaging the piping. That is the whole reason it goes in ahead of any component you expect to pull.
5) Is the Nibco 733-4 union dezincification resistant for hydronic and irrigation lines?
Yes, it is a dezincification resistant cast bronze body, which matters on hydronic heating loops and irrigation where water chemistry attacks lower grade yellow brass. Material and workmanship conform to ASME B16.18.
6) Which Nibco part number do I order for a 3/4 inch solder by male thread union?
The 3/4 inch 733-4 is MPN B260250. For reference across the range: 1/2 inch is B260100, 1 inch is B260350, 1-1/2 inch is B260550 and 2 inch is B260650.
7) Can I use the 733-4 union on a fire protection or commercial HVAC system?
Yes. Nibco lists this union for commercial plumbing, fire protection, heating, HVAC, industrial, irrigation and residential plumbing service. The only hard restriction is potable water, which is off limits in the US for this bronze alloy.
8) Do I need to take the Nibco 733-4 union apart before soldering it?
Yes, back the nut off and separate the union before you apply heat. Sweating the cup with the seat faces clamped together risks distorting the ground seat and wrecking the seal. Solder the copper cup end, let it cool, then reassemble and pull the nut up. Nibco publishes copper fitting installation instructions for the heating and joint procedure.
9) Does the threaded end of this Nibco union need thread sealant?
The male NPT end does, same as any tapered pipe thread, so use tape or pipe dope rated for the system. The union's own joint does not, because it seals on a machined metal seat pulled up by the nut rather than on the threads.
How fast can I get the Nibco B260350 delivered?
Most orders ship the same day from our distribution partners, with quick delivery throughout the continental U.S. Need it urgently? Contact Us for expedited shipping options.
Can I return it if it doesn’t work for me?
Yes—ZenSupply offers a hassle-free return policy. If the product isn’t the right fit, reach out to our support team for a return authorization or setup a return by following our return instructions.
Does the Nibco B260350 come with a warranty?
Absolutely. The Nibco B260350 is backed by a manufacturer’s warranty. For full warranty terms, check the product documentation or Contact Us.
How do I get technical support or installation help for the Nibco B260350?
You can call, text, or email our expert support team for fast answers. We’re here to help with product selection, installation tips, and troubleshooting. Contact Us
Why buy the Nibco B260350 from ZenSupply?
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