Kunkle Stainless Steel Liquid Relief Valve Models 71S, 171, 171P, 171S

Cast iron valve is a durable pressure relief valve. Model 171S is suitable for sanitary and edible applications. This liquid relief valve can also be used with caustic liquid materials. Best used for bypass relief, pressure regulation, overpressure relief of pumps, tanks and hydraulic systems.

Model Descriptions:

Liquid Relief Valves

  • Model 71S: Cast iron body with stainless steel (SS) seat and disc. Pressure-tight hood.
  • Model 171: Carbon steel (CS) with SS seat and disc. Pressure-tight hood.
  • Model 171P: Same as Model 171 with packed lift lever.
  • Model 171S: All 316 SS construction, including spring. Available with pressure-tight hood or packed lift lever.


  • Suitable for back pressure to 50 PSIG.
  • Seats lapped for optimum performance.
  • Ball pivot between disc and spring corrects misalignment and compensates for spring side thrust.
  • SS springs
  • Each Kunkle valve is tested and inspected for pressure setting and leakage.


  • Overpressure relief and protection of pumps, tanks, lines and hydraulic systems. Acid, caustic, ammonia and other corrosive liquids requiring iron, steel or SS materials.
  • Pressure regulation.
  • By-pass relief.
  • Model 171S is all 316 SS, potentially suitable for sanitary applications depending on requirements.

Pressure and Temperature Limits:

  • Model 71S
    • 1 to 250 PSIG
    • -20° to 406°F
  • Models 171, 171P, 171S
    • 1 to 400 PSIG
    • -20° to 550°F

Please refer to the Kunkle Catalog or Contact Us for additional information.

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