Watts Water Technologies FV-4M1 Automatic Float Vent

Description:

The Watts FV-4M1 Automatic Float Vent is a 1/4 inch automatic air vent valve designed to continuously remove trapped air from hot or cold water hydronic systems while preventing water loss. Commonly installed in boilers, hydronic heating systems, chilled water systems, radiant heating systems, HVAC equipment, circulation loops, and commercial water distribution systems. The float-operated mechanism automatically vents accumulated air and reseals once air is expelled, helping maintain system efficiency, reduce noise, and prevent air-related performance issues.

Applications:

The Watts FV-4M1 is widely used in residential and commercial hydronic heating systems, boiler rooms, radiant floor heating systems, chilled water systems, heat exchangers, circulation loops, mechanical rooms, and HVAC installations. The valve automatically removes trapped air during operation and can also function as an anti-vacuum device when systems are drained. Its high-temperature resistant float and glycol compatibility make it suitable for heating and cooling applications requiring reliable automatic air elimination.

Technical Specifications:

• Brand: Watts
• Model: FV-4M1
• Product Type: Automatic Float Vent / Air Vent Valve
• Valve Size: 1/4 in.
• Connection Type: Male NPT Threaded
• Body Material: Brass
• Cover Material: Brass
• Float Material: High-Temperature Resistant Polyethylene
• Seal Material: Silicone Rubber
• Maximum Working Pressure: 150 PSI (10 Bar)
• Minimum Working Pressure: 1.45 PSI (10 kPa)
• Maximum Operating Temperature: 240°F (116°C)
• Minimum Operating Temperature: 33°F (5°C)
• Service Media: Hot or Cold Water
• Glycol Compatible: Yes
• Vent Type: Automatic Float Operated
• Installation Orientation: Vertical
• Function: Automatic Air Removal and Vacuum Relief
• Maintenance: Disassemblable for Inspection and Cleaning
• Application: Hydronic Heating and Water Distribution Systems

Common Replacements:

• Watts FV-4M1-1/8 
• Watts FV-4M1-1/2 
• Watts FV-4M1-3/4