The Armstrong B3 Cast Iron Float and Thermostatic Steam Trap is part of the B & BI Series, engineered for reliable heating service where continuous condensate drainage and high air-venting capacity are essential. Built with an ASTM A48 Class 30 cast iron body rated to 125 psig at 353°F (8.5 barg at 178°C), the B3 handles capacities up to 1,410 lb/hr (640 kg/hr) with a maximum operating pressure of 30 psig (2 bar).
The thermostatic air vent element responds to the pressure-temperature curve of steam across a range from less than 20″ (500 mm) Hg vacuum to 30 psig (2 bar), making the B3 an excellent choice for vacuum return heating systems. Continuous drainage means no condensate backup — the float mechanism responds instantly to changing condensate loads.
Key Features
- Continuous condensate drainage with no backup
- High air-venting capacity via thermostatic element
- ASTM A48 Class 30 cast iron body rated to 125 psig
- Maximum operating pressure of 30 psig (2 bar)
- Capacity up to 1,410 lb/hr (640 kg/hr)
- Operates from vacuum to 30 psig
- 3/4″ (20 mm) screwed connection
Applications
Designed for heating service including radiators, unit heaters, and heat exchangers where continuous drainage and rapid air venting improve system efficiency. Well-suited for vacuum return systems. Available with screwed connections in 3/4″ (20 mm) size with horizontal flow direction.
