Maxitrol 12A39 Vent Limiter

The Maxitrol 12A39 Vent Limiter is a critical brass gas regulator accessory engineered for indoor gas pressure regulator installations where piping a vent line to the outdoors is impractical or prohibited by code. This 3/8" NPT automatic vent limiter features a precision-machined ball check valve mechanism that permits free inhalation for sensitive diaphragm movement during normal operation but limits gas escape to within ANSI Z21.80 and ANSI Z21.18 standards in the event of a diaphragm rupture. Designed specifically for high-capacity applications, the 12A39 is compatible with Maxitrol 325-5 and 325-5L series regulators, as well as the OPD210D overpressure protection device, ensuring seamless integration into commercial and industrial gas trains without compromising safety or system response time.

Technical Benefits for Professionals:

• Code Compliance: Facilitates indoor regulator venting requirements by eliminating the need for expensive and labor-intensive vent piping to the building exterior.
• Precision Engineering: Manufactured from high-grade, corrosion-resistant brass with a 3/8-inch NPT connection for a secure, leak-free seat on the regulator vent port.
• Position Sensitivity: Designed for installation in a vertical upright position to ensure the automatic vent limiting ball check functions at peak efficiency.
• System Versatility: Direct replacement part for Maxitrol gas regulators used in residential or commercial manifolds where compact footprints are required.

Common Questions:

Does the 12A39 require a multi-stage vent line?
No. When installed on a compatible vent-limited regulator, this component acts as the atmospheric breather, satisfying code requirements for venting without a dedicated pipe to the atmosphere.

Can I install this vent limiter horizontally?
For the internal ball check to reset and function correctly according to specifications, these limiters must be installed in the upright vertical position on the top of the regulator diaphragm powerhouse.

What happens if the regulator diaphragm fails?
The Maxitrol 12A39 is designed to restrict gas leakage to a safe, negligible level (less than 2.5 CFH for natural gas) as dictated by national fuel gas codes, preventing hazardous accumulation in the mechanical room.

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.