Nibco 741 Class 125 Companion ...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$139.99
Nibco 741 Class 125 Companion Flange C - Cast

Nibco 741 Class 125 Companion Flange C - Cast

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Model: B305356

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

$139.99
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The flange features a solder cup and flange face. This fitting provides a means for adapting a solder connection to a flange 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
  • Conforms to MSS SP-106

Copper Fittings Installation Instructions

Manufacturer Resources

Product Specs

All Basic Material:
Bronze
Classification:
Solder Pressure Companion Flanges
End Connection:
Solder
Metal End Connection Type:
C x Flange
Product Group:
Fitting
Product Type:
Solder Pressure Companion Flanges
System Use:
Commercial Plumbing, Fire Protection, Heating, HVAC, Industrial, Irrigation, Residential Plumbing
Product Subgroup:
Flange
Department:
Plumbing

Nibco B305356 – Frequently Asked Questions

1) How do I connect copper tube to a flanged pump or valve without threading?
The Nibco 741 companion flange is the adapter for exactly that. One end is a solder cup that takes copper tube, the other is a Class 125 flange face that bolts to the flanged pump, valve, tank nozzle or strainer. Solder the cup to the tube, then bolt the flange up with a gasket and bolts. It saves cutting threads on copper and gives you a bolted joint you can break later for service.
2) Will a Nibco 741 flange bolt to my existing Class 125 cast iron flange?
Yes. The 741 is a Class 125 flange, so the bolt circle, bolt count and face dimensions follow the Class 125 flanged pattern for that pipe size and it mates with any other Class 125 flange of the same nominal size. Class 125 and ANSI Class 150 flat-face patterns share the same drilling at these sizes, which is why pumps and valves in HVAC and plumbing service bolt up interchangeably. You supply the gasket and bolts separately.
3) Can I use the Nibco 741 bronze flange on a potable water line?
No. Use in U.S. drinking water applications is prohibited after January 3, 2014. The 741 is cast from ASTM B584 alloy C84400, which is not a low lead alloy for potable service. Keep it on non-potable work: hydronic heating and chilled water, HVAC, fire protection, industrial process and irrigation. For domestic water you need a lead free flange instead.
4) What pipe sizes does the Nibco 741 companion flange come in?
Eleven sizes, 1/2, 3/4, 1, 1-1/4, 1-1/2, 2, 2-1/2, 3, 4, 5 and 6 inch. That covers the full run from small branch takeoffs to 6 inch mains, so a mechanical contractor can standardize on one flange family across a building. The solder cup size matches the nominal copper tube size you are soldering into.
5) What standard does the Nibco 741 companion flange conform to?
MSS SP-106, the standard covering cast bronze flanges and flanged fittings for Class 125 and 150 service. If your drawing or spec calls out MSS SP-106 cast bronze companion flanges, the 741 meets the callout. The body is cast bronze, ASTM B584 alloy C84400.
6) Is a bronze companion flange better than a steel one on a copper system?
On copper, bronze is the match. A cast bronze flange soldered directly to copper tube keeps the joint in the same metal family and avoids the galvanic couple you get putting carbon steel against copper in a wet system. A steel flange needs a threaded or grooved adapter and a dielectric break to do the same job. The 741 also states dezincification resistance, which matters where water chemistry attacks ordinary brass. Where it does not work is potable water, and it is not a threaded flange, so the pipe end has to be plain copper tube you can solder.
7) Do I get bolts and a gasket with the Nibco 741 flange?
The 741 is the flange alone, a cast bronze body with a solder cup on one end and a flat flange face on the other. Bolts, nuts and the gasket are separate and sized to the Class 125 bolt pattern for your pipe size. On a pump connection you typically need two flanges, one on each side, plus the gasket set for each joint. Order solder, flux and fittings for the tube side as usual.
8) Can I solder a companion flange without warping the face?
It is the usual concern on the larger sizes. The 741 is a cast bronze body, and the mass of the casting takes more heat than a wrought fitting, particularly from 2-1/2 inch up through 6 inch. Heat the flange hub evenly around the cup rather than concentrating on the face, and let the joint cool before you torque the bolts down on the gasket. Nibco publishes copper fittings installation instructions covering the soldering procedure.
9) Is the Nibco 741 flange approved for fire protection piping?
Fire protection is one of the listed system uses for the 741, along with commercial plumbing, heating, HVAC, industrial and irrigation. It is a Class 125 solder companion flange in cast bronze, so it goes on copper fire protection runs where a flanged connection to a valve or riser component is needed. Confirm the pressure class against your sprinkler system design before you specify it.
How fast can I get the Nibco B305356 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 B305356 come with a warranty?
Absolutely. The Nibco B305356 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 B305356?
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
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