Universal Low Pressure Style - U3, UR

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Universal Low Pressure Style - U3, UR

The Universal Low Pressure (U3, UR) check valve is a one piece body machined from bar stock and is designed for minimum pressure drop.  The valve is light-weight, compact, and provides maintenance-free dependable service.  NPT threads are per ASME B1.20.1 and this valve is also available with ISO 7 "Rp" threads (UR). For applications above 3000 PSIG, view our UN-10 series. For applications where weld joint are required view our UN-SW series.

Many valves in this series can be supplied with B16.34 certification. Give us a call for more information.

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NOTES (DIMENSIONS TABLE)
*May be larger and/or round.
**Consult factory for ISO 7 "Rp" threads.

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View U3 Dimensions in PDF format

Nominal Size Size Code A Hex Size B* C** Orifice Diameter
3/8 C 2.16 13/16 3/8 NPT 0.348
1/2 D 2.71 1-1/8 1/2 NPT 0.464
3/4 F 2.95 1-1/4 3/4 NPT 0.593
1 H 3.64 1-5/8 1 NPT 0.890
1-1/4 I 3.91 2-1/4 1-1/4 NPT 1.135
1-1/2 J 4.36 2-12 1-1/2 NPT 1.385
2 K 5.85 3 2 NPT 1.555
2-1/2 L 5.50 3-3/4 2-1/2 NPT 1.555
3 M 6.25 4-1/2 3 NPT 2.025
4 N 7.13 5-1/2 4 NPT 2.560
  • 316 Stainless Steel (SS)
  • Alloy B (HB)
  • Alloy 20 (A2)
  • Alloy C-276 (HC)
  • Brass (BR)
  • Alloy 400 or MONEL® (MO)
  • Carbon Steel (CS)
  • Titanium (TI)
  • Body Material Availability Non-Shock Pressure-Temperature Rating

    316 Stainless Steel (SS)
    Carbon Steel (CS)
    Brass (BR)

    Standard 3/8" - 3"
    3000 psig @ 100°F
    (1500 PSIG for o-ring seats)
    4"
    1500 psig @ 100F
    Alloy 20 (A2)
    Alloy C-276 (HC)
    Alloy 400 or MONEL®(MO)
    Semi-standard
    Alloy B (HB)
    Titanium (TI)
    Contact the factory for these or other materials.

    Seat material and spring material selection may limit the recommended service temperature.
    See seat ratings, spring ratings, and body material ratings for their respective recommended service temperatures.
    Consult the factory for reduced P-T rating above 100 °F. Standard spring material is 316 Stainless Steel.

    Size Cv
    3/8 1.9
    1/2 4.3
    3/4 7.2
    1 11.0
    1-1/4 19.0
    1-1/2 31.9
    2 42.0
    2-1/2 50.0
    3 89.0
    4 140

    P
    R
    E
    S
    S
    U
    R
    E

    D
    R
    O
    P

    P
    S
    I

    FOR WATER AT 72°F

    WATER FLOWRATE - GPM

    Note: All flow curves and Cv values presume the valves are fully open with 1/2 PSI cracking pressure springs. Consult the factory for more information.

    SIZE PART NUMBER SS, CS & Alloys BRASS
    3/8 U3C 3.0 oz. 3.3 oz.
    1/2 U3D 8.5 oz. 9.1 oz.
    3/4 U3F 9.6 oz. 10.1 oz.
    1 U3H 1.2 lb. 1.3 lb.
    1-1/4 U3I 2.9 lb. 3.2 lb.
    1-1/2 U3J 3.6 lb. 3.9 lb.
    2 U3K 6.5 lb. 7.2 lb.
    2-1/2 U3L 9.2 lb. 10 lb.
    3 U3M 14.3 lb. 15.5 lb.
    4 U3N 21.7 lb. 23.9 lb.
    Valve weights are approximate.
    Valve Style Size Range Body Materials Other Options Allowable Seat Materials Other Options Standard Cracking Pressures Other Options More Info. Standard Spring Material More Info.
    U3 3/8" - 1-1/4" 316 SS
    Brass
    AFLAS®
    EPDM
    "Metal to Metal"
    PTFE
    Buna-N
    Kalrez®
    Neoprene
    Viton®
    1/8 PSI
    1/2 PSI
    1.5 PSI
    3.5 PSI
    316 SS
    U3 3/8" - 1-1/4" C. Steel AFLAS®
    Buna-N
    Kalrez®
    "Metal to Metal"
    Neoprene
    PTFE
    Viton®

    1/8 PSI
    1/2 PSI
    1.5 PSI
    3.5 PSI
    316 SS
    U3 1-1/2" - 2" 316SS
    Brass
    AFLAS®
    Buna-N
    EPDM
    Kalrez®
    "Metal to Metal"
    Neoprene
    PTFE
    Viton® 
    1/8 PSI
    1/2 PSI
    1.5 PSI
    316 SS
    U3 1-1/2" - 2" C. Steel AFLAS®
    Buna-N
    Kalrez®
    "Metal to Metal"
    Neoprene
    PTFE
    Viton®
    1/8 PSI
    1/2 PSI
    1.5 PSI
    316 SS
    U3 3/8" - 2" Alloy 20
    Alloy C-276
    AFLAS®
    Buna-N
    EPDM
    Kalrez®
    "Metal to Metal"
    Neoprene
    PTFE
    Viton®
    1/2 PSI Alloy C-276
    U3 3/8" - 2" Alloy 400 or MONEL® AFLAS®
    Buna-N
    EPDM
    Kalrez®
    "Metal to Metal"
    Neoprene
    PTFE
    Viton®
    1/2 PSI Alloy 400 or MONEL®
    U3 3/8" - 2" Alloy B AFLAS®
    Buna-N
    EPDM
    Kalrez®
    "Metal to Metal"
    Neoprene
    PTFE
    Viton® 
    1/2 PSI Alloy B

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