74, 1/2" x 3/4" STRAIGHT STEAM UNIT HEATER AIR VALVE Winters Thermometers DESCRIPTION & FEATURES: Economical 4

DESCRIPTION & FEATURES: Economical 4

100 compliant (EN837-1 available)

• Install 6-10" (150-250mm) above horizontal return and 18" (450mm) above the boiler water line

Series 221

74, 1/2" x 3/4" STRAIGHT STEAM UNIT HEATER AIR VALVE Winters Thermometers DESCRIPTION & FEATURES: Economical 4Special 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