1/8" Non-Adjustable Angle Steam Radiator Air Valve

Bell & Gossett 401440 Hoffman Specialty Model 40 Radiator Steam Air Vent – 1/8" Angle

The Bell & Gossett 401440, also known as the Hoffman Specialty Model 40, is an angle-pattern air vent designed for use in low-pressure steam heating systems. This 1/8 inch NPT vent automatically discharges air from radiators, allowing steam to enter freely and ensuring even heat distribution throughout the system. It is a float-type, non-vacuum vent suitable for standard residential steam applications.

Built with a single fixed vent port, the Model 40 delivers consistent venting without adjustment. Its compact size makes it ideal for installations with limited clearance, and its operating range is optimized for pressures up to 6 psig, with a maximum rated pressure of 10 psig.

Product Features

• Type: Float-actuated steam radiator vent
• Connection: 1/8 in. MNPT angle pattern
• Port Configuration: Fixed orifice for uniform venting
• Application: One-pipe steam systems in residential buildings
• Operation: Non-vacuum vent – does not close under vacuum conditions

Technical Specifications

• Model: Hoffman Specialty Model 40
• Part Number: 401440
• Thread Size: 1/8 in. NPT
• Orientation: Angle
• Maximum Operating Pressure: 6 psig (0.4 bar)
• Maximum Pressure: 10 psig (0.7 bar)

Installation Guidelines

This valve should be installed vertically on the radiator’s air vent tapping using appropriate thread sealant for steam applications. Ensure the vent remains upright to maintain correct float operation. Avoid overtightening to prevent damage to the valve body or threads. Use in non-vacuum systems only.

Recommended Applications

• Low-pressure steam radiators in single-pipe heating systems
• Residential properties requiring air venting at the radiator level
• Installations where non-adjustable, consistent venting is acceptable