1/8" Straight Steam Convector Air Valve

Hoffman 401475 1/8" Straight Pattern Steam Air Vent for Convectors and Radiators

The Hoffman 401475 is a straight-type steam air valve with a 1/8 inch male NPT connection, engineered for use in low-pressure steam heating systems. Designed for convectors and radiators, this air vent provides automatic venting of trapped air to support balanced steam distribution and efficient heat transfer throughout the system.

Featuring a disc-type venting mechanism, the valve includes an internal check to prevent backflow and resist fouling from system debris. It is suitable for residential and commercial steam heating applications requiring consistent air removal from terminal heating units. The vent body is serviceable and may be disassembled for routine maintenance without removal from the system piping.

Product Features

• Venting Type: Disc-type automatic air vent for steam applications
• Configuration: Straight pattern with 1/8 in. MNPT connection
• Internal Check: Built-in check valve prevents reverse flow or steam blow-through
• Service Access: Can be opened for cleaning while installed in-line
• Application: Designed for convectors, radiators, and other steam heat terminals

Technical Specifications

• Model: 401475
• Connection Size: 1/8 inch MNPT
• Orientation: Straight
• Operating Pressure: For low-pressure steam systems
• Construction: Corrosion-resistant internal components; durable vent body

Installation Notes

Install the Hoffman 401475 at the designated air vent tapping on the radiator or convector unit. Apply thread sealant appropriate for steam service. Ensure vertical orientation for proper vent operation. Periodic inspection is recommended in high-condensate or sediment-prone systems. Do not overtighten during installation to avoid thread damage.

Applications

• One-pipe and two-pipe low-pressure steam systems
• Residential and light commercial heating zones
• Terminal heating units requiring automatic air elimination