Hoffman Specialty 401485 Water Vent

The Hoffman Specialty 401485, or Model 78 Water Main Vent Valve, is a high-capacity automatic air vent designed for efficient air elimination in hydronic heating and cooling systems. Engineered for closed-loop hydronic systems, this vent features a 3/4" NPT connection and is built to withstand a maximum pressure of 150 PSI. Its primary function is to purge air from water mains and large distribution lines, preventing air-bound system issues that lead to restricted flow and excessive noise. The heavy-duty cast iron construction and corrosion-resistant internal float mechanism ensure long-term reliability in high-temperature boilers and radiators. As a direct OEM replacement for the standard Hoffman Model 78, the 401485 maintains system efficiency by continuously venting accumulated gases without manual intervention. Technicians rely on the Hoffman Specialty 78 for industrial, commercial, and residential applications where high-pressure ratings and reliable air venting are required for peak thermal performance.

Key Benefits:

• High-Pressure Capability: Rated for system pressures up to 150 PSI, making it suitable for demanding commercial and industrial hydronic loops.
• Automatic Air Venting: Continuously removes trapped air to improve heat transfer and reduce pump cavitation.
• Direct Compatibility: Replaces existing Hoffman Specialty 401485 units with a standard 3/4" NPT connection for seamless field retrofits.
• Heavy-Duty Durability: Rugged design handles high temperatures and provides consistent operation in closed-loop systems.

Common Questions:

What is the difference between Hoffman 401485 and Model 78?
The 401485 is the specific part number for the Model 78 Water Main Vent Valve; they are the same technical component and are used interchangeably in parts catalogs.

Can this be used for steam heating applications?
While primarily designed for hydronic and water systems, it is used in specific water-based heating loops. Always verify the specific discharge requirements for your system before installation.

Where should the Hoffman Model 78 be installed?
For maximum air elimination, install the vent at high points in the system piping or on air separators where air naturally accumulates.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.