74, 1/2" x 3/4" STRAIGHT STEAM UNIT HEATER AIR VALVE Winters Thermometers • Maximum vessel pressure 25

• Maximum vessel pressure 25 psi (1

100 compliant (EN837-1 available)

DESCRIPTION & FEATURES: Economical 4

• Adjustable from 1⁄4" - 20" (8-508mm) Hg vacuum - factory set at 2” (51mm) Hg vacuum

74, 1/2" x 3/4" STRAIGHT STEAM UNIT HEATER AIR VALVE Winters Thermometers • Maximum vessel pressure 25Special Steam Vents Model 74 Part No. 401429 Steam Unit Heater Air Valve Float type thermostatic vent Single non adjustable port 12" NPT female and 34" 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) *Drop away pressure (maximum pressure against which the vent can open). Hoffman Special Steam Vent