Watts 0556030 Valve

The Watts 0556030 (Series LFN36M1) is a high-performance 1/2 inch vacuum relief valve engineered for critical protection in closed systems. Designed for water heater vacuum relief and low pressure steam service, this valve automatically vents to the atmosphere when a vacuum occurs. This action prevents negative pressure from siphoning the tank, which often leads to tank collapse or equipment burnout. Built with a lead-free brass body and a low profile design, it is ideal for tight installations in domestic water heaters, jacketed kettles, and supply tanks. This model is the direct field replacement for legacy parts including N36-1/2, 0121402, and 36A-1/2. Rated for a maximum working pressure of 200 psi and steam up to 15 psi, it features a durable Buna-N O-ring and a protective cap to shield internal components from debris. Professionals rely on its ANSI Z21.22 rating and CSA certification for uncompromising system integrity.

• Automatic Atmospheric Venting: Instantly eliminates vacuum conditions to prevent siphoning and structural damage to tanks.
• Lead-Free Brass Construction: Meets stringent potable water requirements with a corrosion-resistant lead-free body.
• Versatile Application Range: Rated for temperatures up to 250°F, making it suitable for both hot water and steam systems.
• Compact Low Profile: 1/2" MNPT connection allows for easy retrofitting in confined mechanical spaces.
• Protection for Critical Hardware: Prevents "dry firing" and burnout in water heaters by maintaining full water levels.

• Can this be used for back-siphonage backflow prevention? No, while the Watts 0556030 provides vacuum relief, it is not a substitute for a dedicated backflow preventer like the Watts 288A series.
• What is the venting capacity of the LFN36M1? This valve offers a 15 CFM venting capacity to handle rapid pressure drops in commercial and residential systems.
• How do I install this on a steam system? For steam service, technicians should use a pigtail siphon to protect the valve’s internal seals from direct live steam damage.

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.