Pump connectors constructed of stainless steel hose and braid are the HVAC industry’s most popular pump connector. Unisource stainless steel pump connectors combine a close-corrugation 300 series stainless steel hose with a tightly woven stainless steel overbraid. Sizes 8 inch and larger utilize a braided-braid reinforcement, insuring a strong pressure safety factor in high pressure-thrust situations. Flanges, threaded ends, or other fittings are welded to each end. Every assembly is leak tested under water to insure that they are leak-free. Carbon steel end fittings are painted. Assemblies are individually packaged and standard flanged connectors are packed in double wall corrugated boxes with anti-crush packaging between the flanges.
Stainless steel braided connectors are a great overall solution for connection to cold and hot water pumps (relatively unaffected by temperature) and they are impervious to today’s water conditioning chemicals.
Unisource offers most standard stainless steel pump connectors in two styles–industry standard short overall length and our “L” style, which are longer with more live hose length. These assemblies provide more lateral offset to accommodate equipment settling, plus the extra length helps to isolate noise and vibration better than the short length connectors.
In addition to standard pump connectors, on this page you will find our reducing connectors, CSA rated connectors for natural gas, and special order connectors where you choose the length, type of end fittings and material, number of braids, etc.
Please also check out our website sections on stainless steel braided Seismic Loops, and our Connectors for Copper Piping. Also more information on hose specifications can be found in our Flexible Metal Hose section.
Contact us for the name of a Unisource HVAC products distributor in your area.
Series 401 & 401-L Threaded Pump Connectors
Unisource Series 401 & 401-L stainless steel braided flex connectors are the standard of the industry for a rugged, versatile flex product to connect piping to vibrating mechanical equipment.
Series 401 & 401-L stainless steel connectors combine 300 series corrugated stainless steel hose and braid with weld-on carbon steel end fittings for a high-pressure assembly. Standard connectors with stainless steel end fittings are also available. Unisource starts with a high core-count inner hose for greater flexibility and better noise and vibration control efficiency. Many manufacturers utilize a less expensive wide-pitch corrugated hose. A tightly woven stainless steel braid provides high-pressure ratings, even in high-temperature heating water applications. Series 401 threaded flex connectors are made to traditional industry standard overall lengths. These connectors are designed to provide good efficiency for noise and vibration control. Series 401-L are longer length connectors, built for even greater noise and vibration control, and a minimum of 2” permanent lateral offset.
Series 401 Submittal
Series 401-L Submittal
Product Brochure
Hose |
End Fittings |
Pressure Range |
Sizes |
Braid |
| Series 300 stainless steel annular corrugated hose | Painted carbon steel MNPT are standard. Stainless steel ends available upon request | 250 PSIG to 990 PSIG (Depending on size) | 1/2″ through 4″. Smaller and larger sizes available by custom order | 300 Series stainless steel |
Series 402 & 402-L Flanged Pump Connectors
Series 402 & 402-L stainless steel flex connectors combine 300 series corrugated stainless steel hose and braid with weld-on carbon steel flanges for a high-pressure assembly. Unisource starts with a high corr-count inner hose for greater flexibility and better noise and vibration control efficiency. Many manufacturers utilize a less expensive wide-pitch corrugated hose. A tightly woven stainless steel braid provides high-pressure ratings, even in high-temperature heating water applications. Series 402 is made to traditional industry standard overall lengths. These connectors are designed to provide good efficiency for noise and vibration control. Series 402-L are longer length flex connectors, built for even greater noise and vibration control, and a minimum of 2” permanent lateral offset.
Series 402 Submittal
Series 402-L Submittal
Product Brochure
Hose |
End Fittings |
Pressure Range |
Sizes |
Braid |
| Series 300 stainless steel annular corrugated hose | Painted carbon steel 150# plate flanges are standard. Stainless steel flanges available upon request | 150 PSIG to 455 PSIG (Depending on size) | 1-1/2″ through 14″. Smaller and larger sizes available on special order | Series 300 stainless steel. Sizes 8″ and larger are braided braid |
Series 403 Groove x Groove
& Series 404 Groove x Flange Pump Connectors
Unisource Series 403 & 404 stainless steel braided flex connectors are the standard of the industry for a rugged, versatile flex product to connect piping to vibrating mechanical equipment.
Series 403 groove x groove and Series 404 groove x flange stainless steel connectors combine 300 series corrugated stainless steel hose and braid with carbon steel end fittings for a high-pressure assembly. Standard connectors with stainless steel end fittings are also available. Unisource starts with a high corr-count inner hose for greater flexibility and better noise and vibration control efficiency. Many manufacturers utilize a less expensive wide-pitch corrugated hose. A tightly woven stainless steel braid provides high-pressure ratings, even in high-temperature heating water applications. Series 403 and 404 flex connectors are made to traditional industry standard overall lengths. These connectors are designed to provide good efficiency for noise and vibration control. Series 403-L and 404-L are longer length flex connectors, built for even greater noise and vibration control, and a minimum of 2” permanent lateral offset.
Series 403 & Series 404 – Brochure
Series 403 Submittal
Series 404 Submittal
Hose |
End Fittings |
Pressure Range |
Sizes |
Braid |
| Series 300 stainless steel annular corrugated hose | Painted carbon steel 150# plate flanges or schedule 40 grooved ends | 140 PSIG to 455 PSIG (Depending on size) | 2″ through 12″. Smaller and larger sizes flex connectors available on special order. | Series 300 stainless steel. Sizes 8″ and larger are braided braid |
Series 405 Reducing Flanged Pump Connectors
Unisource Series 405 connectors are a material and labor saving device designed to provide vibration and noise isolation when connected between piping and vibrating equipment. These special connectors are intended to facilitate a reduction in pipe size when connecting to mechanical equipment. They are normally installed on the discharge side of HVAC pumps. Since Series 405 connectors incorporate a reduced size flange on one side, it eliminates having to install both a straight flex connector and a pipe reducer. Series 405 flex connectors utilize Superflex series 300 stainless steel hose and braid, carbon steel flanges, and carbon steel bell reducers. Longer length flex connectors are available on request to provide additional lateral deflection and increased vibration control efficiency.
Series 405 – Brochure
Series 405 – Submittal
Hose |
End Fittings |
Pressure Range |
Sizes |
Braid |
Concentric Reducer |
| Series 300 stainless steel annular corrugated hose | Painted carbon steel 150# plate flanges. Other end configurations available | 160 PSIG to 395 PSIG (Depending on size) | 2-1/2″ x 2″ through 12″ x 10″. Smaller and larger sizes available on special order | Series 300 stainless steel. Sizes 8″ and larger are braided braid | Painted carbon steel, Sch. 40 |
Series 406, 407, 408, & 409 Straight CSA Rated Flex Connectors For Natural Gas
Unisource CSA rated flex connectors are specifically designed for use as a flex connector in medium pressure natural gas applications. These heavy-duty connectors are CSA certified and can be fabricated with any of four different end configurations:
Each flex connector assembly is factory pressure-tested and is rated to 350 PSIG working pressure. Safety factors range from a minimum of 4:1 in 4” size to greater than 15:1 in size 1/2”. Finished assemblies are labeled with manufacturer, part number, maximum working pressure, certification report number, serial number and CSA logo. Unisource CSA rated connectors are intended to provide vibration isolation and accommodate offset pipe motion. Unisource recommends a minimum 24” overall length, but the user may specify other overall lengths in keeping with the hose ratings for static and dynamic bend radius.
- Series 406 – 150# carbon steel weld neck flanges.
- Series 407 – Sch 80 male carbon steel NPT hex ends.
- Series 408 – Sch 80 carbon steel beveled weld ends.
- Series 409 – 300# ANSI carbon steel RFSO flanges
Series 406, 407, 408, 409 Straight CSA Rated Flex Connectors – Brochure
CSA Rated Straight Flex Connectors – Submittal
Hose |
End Fittings |
Pressure Range |
Sizes |
Braid |
| Series 300 stainless steel annular corrugated hose | Style 49 – 150# carbon steel weld neck flanges; Style 58 – 300# carbon steel raised-face flanges; Style 50 – Sch 80 male carbon steel NPT hex ends; Style 52 – Sch 80 carbon steel beveled weld ends | 335 PSIG to 350 PSIG (Depending on size). | 1/2″ through 4″ | Series 300 stainless steel. Single or double braid, depending on size |
SF21 Special Metal Hose Connectors
Unisource stainless steel pump connector (as well as bronze hose) can be made to order upon request with typically no minimum quantity. Order by size and choose either the overall length or live length you prefer, along with the weld on fittings you would like on each end. Important considerations in deciding on the proper assembly would be the working pressure, media, type of bending or vibration, velocity of media, and temperature. Choose either painted carbon steel ends or stainless steel.
Visit our Flexible Metal Hose section for more information and specifications on our broad line of corrugated and braided metal hose.
Superflex options:
- Choose your overall flex connector length
- Select either single braid or double braid
- The fitting material can be carbon steel, stainless steel, or copper
End Fitting Styles:
- Sch 40 or Sch 80 pipe threads
- Hex wrenching surface
- Beveled weld ends
- Plate, raised-face, and weld neck flanges
- Floating flanges
- 150#, 300#, or 600# drill patterns
- 150# or 3000# unions
- JIC
- Grooved
- Copper sweat (tube) or copper hex male NPT
Flexible Metal Hose – Full Catalog
SF21 Metal Hose – Threaded End Submittal
SF21 Metal Hose – Flanged End Submittal
