The Watts 0590715, also known as the FV-4M1-1/8, is a heavy-duty automatic air vent designed for high-performance venting in residential and commercial hydronic heating systems. Featuring a rugged brass body and cover, this 1/8 inch NPT vent is engineered to purge trapped air from hot or cold water distribution lines automatically. With a maximum pressure of 150 PSI and a temperature rating up to 240°F, it is a reliable choice for demanding environments, including glycol-based systems. The polyethylene float and silicone rubber seal are designed to ensure the valve plug remains secure once air is displaced, preventing water leaks while maintaining system pressure. This component also functions as an anti-vacuum device, permitting air entry during system drainage to prevent collapsing. For long-term maintenance, the unit can be fully disassembled for inspection and cleaning, ensuring consistent system pressure and efficiency. Key Benefits: High Temperature Resilience: Rated for up to 240°F, making it suitable for high-temperature hydronic and glycol loops. Durable Brass Construction: The solid brass body and cover provide superior corrosion resistance and longevity on the job site. Automatic Air Purging: Continuously removes air pockets to prevent pump cavitation and noise in the piping. Serviceable Design: Can be easily disassembled for cleaning, reducing the need for complete replacements if debris enters the line. Anti-Vacuum Functionality: Acts as a vacuum breaker to facilitate easy system draining and prevent negative pressure issues. Common Questions: Is the Watts 0590715 compatible with glycol? Yes, the high-temperature polyethylene float and silicone seals are specifically designed to handle glycol concentrations common in hydronic systems. Can this vent be used on the suction side of a pump? It is typically installed at high points in the system or on air separators where air collects. If used as an anti-vacuum device, it will allow air in during drainage. Does it require manual adjustment? No, the FV-4M1 operates automatically based on the internal float mechanism, though it should be inspected periodically for debris. 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.
