Maxitrol R400S-3/8 Regulator

The Maxitrol R400S-3/8 is a high-performance gas pressure regulator engineered for precision control in low-pressure applications. Featuring 3/8" NPT connections and a double diaphragm balanced valve design, this unit excels at maintaining a stable outlet pressure between 3" to 8" w.c. even when upstream pressures fluctuate. It is rated for a 5 PSI max inlet pressure, making it a reliable choice for commercial cooking equipment, infrared heaters, and residential pilots. The zero-governor capability and rubber seat poppet ensure tight shut-off and sensitive response times. Designed specifically for natural gas and LP-gas mixtures, the R400S-3/8 eliminates the need for external vent piping in most jurisdictions when used with a vent limiting device. For contractors, this means a simplified installation process and consistent BTU output for downstream burners, ensuring optimal combustion efficiency across varying flow rates.

Key Performance Benefits

• Double Diaphragm Design: Provides superior regulation sensitivity and stability under varying load conditions.
• High Flow Capacity: Engineered for high-demand HVACR equipment while maintaining compact dimensions.
• Multi-Poise Mounting: Capable of being installed in upright, horizontal, or vertical orientations for tight mechanical rooms.
• ANSI Z21.18 Certified: Meets rigorous industry standards for safety and reliability in gas appliance pressure regulation.

Common Technical Questions

Can the R400S-3/8 be used with Propane?
Yes, this regulator is compatible with both Natural Gas and Liquid Propane (LP), provided the inlet pressure does not exceed the 5 PSI rating.

Does this unit require a vent line?
In many applications, the Maxitrol R400S-3/8 can be used with a vent limiter, though local mechanical codes should always be consulted regarding atmospheric discharge.

What is the lock-up behavior of this regulator?
The double diaphragm construction allows for excellent lock-up characteristics, preventing pressure spikes during the off-cycle of the burner system.

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.