Vents & Vacuum Breakers

Main Steam Vents

Model 4A Part No.401413 Air Valve (non-vacuum)

  • Float-type thermostatic vent
  • For residential or small one-pipe or two-pipe systems
  • Single non-adjustable port
  • 1/2 NPT female and 3/4  NPT male straight shank
  • Install 6-10″ (150-250mm) above horizontal return and 18″ (450mm) above the boiler water line
  • Maximum operating pressure 2 psig (0.13 bar)*
  • Maximum pressure 10 psig (0.7 bar)

Model 75 Part No. 401434 75H Part No. 401437 Air Valve (non-vacuum)

  • Float-type thermostatic vent
  • For medium and large systems
  • Single non-adjustable port
  • 1/2 NPT female and 3/4 NPT male straight shank
  • Maximum operating pressure*
    • Model 75 3 psig (0.2 bar)
    • Model 75H 10 psig (0.7 bar)
  • Maximum pressure 15 psig (1.0 bar)

Model 76 Part No. 401431 Vacuum Valve

  • Float-type themostatic vent
  • For medium and large one-pipe vacuum systems
  • Single non-adjustable port
  • 1/2 NPT female and 3/4 NPT male straight shank
  • Install 6-10″ (150-250mm) above horizontal return and 8″ (450mm) above the boiler water line
  • Maximum operating pressure 3 psig (0.2 bar)
  • Maximum pressure 15 psig (1.0 bar)

Special Steam Vents

  • Model 3 Part No. 401419 Steam Air Line Valve
  • Thermostatic vent (no float)
  • For Air Line or Paul Systems
  • Inlet 1/8 NPT, outlet 1/4 NPT
  • Maximum operating pressure 25 psig (1.7 bar)* to vacuum
  • Maximum pressure 25 psig (1.7 bar)

Model 4 Part No. 401416 Quick Valve

  • Thermostatic air vent
  • For steam systems and process equipment
  • Operates on temperature change only; does not close against water
  • Must be installed 6-10″ (150-250mm) above horizontal return and 18″ (450mm) above the boiler water line
  • 1/2 NPT female and 3/4 NPT male straight shank
  • Maximum operating pressure 25 psig (1.7 bar)*
  • Maximum pressure 25 psig (1.7 bar)

Model 74 Part No. 401429 Steam Unit Heater Air Valve

  • Float-type thermostatic vent • Single non-adjustable port
  • 1/2 NPT female and 3/4 NPT male straight shank
  • Install 6-10″ (150-250mm) above horizontal return and 18″ (450mm) above the boiler water line
  • Maximum operating pressure 35 psig (2.4 bar)*
  • Maximum pressure 35 psig (2.4 bar)

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