The Maxitrol 325 Series comprises appliance pressure regulators designed for use in residential, commercial, and industrial applications involving natural gas (NAT), propane, and LP gas-air mixtures. These regulators feature a high-leverage valve linkage assembly for positive dead-end lock-up. Models are available for 2 psi, 5 psi, and 10 psi piping systems, with specific configurations offering enhanced corrosion resistance through Imblue Technology™. Proper installation, particularly regarding mounting position and vent limitations, is critical for safe and effective operation. The series includes options for vent limiting devices suitable for indoor use, and vent protectors for outdoor applications.
Regulator Description and Features
The 325 Series regulators are designed for use with petroleum gases, LP gas-air mixtures, and natural gas. They incorporate a high-leverage valve linkage assembly to ensure a positive dead-end lock-up, enhancing safety and reliability. Certain models, designated with a "(B)" suffix in the model number, utilize Imblue Technology™ to increase corrosion resistance and provide additional protection when used in outdoor environments. This technology is specifically designed to protect the regulator from the elements.
Model Specifications
The 325 Series includes several models, each with specific inlet pressure and capacity ratings. The following details are based on information provided in the documentation:
- 325-3(B): Maximum inlet pressure of 2 psi (13.8 kPa) when tested at 10 psi (69 kPa). Maximum individual load of 100,000 Btu/hr. Total capacity of 150,000 Btu/hr (with 3/8" or 1/2" connections).
- 325-5A(B): Maximum inlet pressure of 5 psi (34.5 kPa) when tested at 10 psi (69 kPa). Maximum individual load of 250,000 Btu/hr. Total capacity of 300,000 Btu/hr (with 1/2", 3/4", or 1" connections).
- 325-7A(B): Maximum inlet pressure of 7 psi (with 12A09, 12A39, or 12A49 installed). Maximum individual load of 1,250,000 Btu/hr. Total capacity of 1,250,000 Btu/hr (with 1 1/4" or 1 1/2" connections).
The documentation specifies that all Maxitrol gas appliance regulators must be installed and operated in accordance with Maxitrol’s Safety Warning Instructions (GPRMIEN.ES).
Mounting Position Requirements
The 325 Series regulators are suitable for multi-poise mounting. However, when used in conjunction with a vent limiting device, the regulator must be mounted in a horizontal upright position. The documentation emphasizes the importance of proper installation with gas flowing as indicated by the arrow on the regulator casting. Failure to adhere to these mounting guidelines may compromise the regulator’s functionality and safety.
Venting Considerations
Maxitrol offers vent limiting devices designed for indoor applications. These devices eliminate the need for vent piping to the outside, making them suitable for installations where limiting gas escapement due to diaphragm failure is critical. However, the documentation explicitly states that vent limiting devices should not be used outdoors if exposed to the environment. For outdoor applications, vent protectors are available to ensure proper vent protection. Specific vent connection sizes vary by model:
- 325-3(B): 1/8" NPT
- 325-5A(B): 3/8" NPT
- 325-7A(B): 1/2" NPT
Pressure Drop and Capacity Charts
The documentation includes pressure drop charts to aid in system design and regulator selection. These charts illustrate the relationship between flow rate (expressed in CFH and m³/h) and pressure drop (in inches of water column and kPa). The charts are specific to a gas specific gravity of 0.64. The documentation provides data for flow rates up to 2000 CFH.
Emergency Exposure Limits and Ambient Temperature Limits
The documentation specifies emergency exposure limits for all models, stating a maximum of 65 psi (450 kPa) on the inlet side only. Ambient temperature limits are specified as -40ºF to 205ºF (-40ºC to 96ºC) for all models. Operating outside these temperature limits may affect regulator performance and longevity.
Safety Notices and Warnings
The documentation includes several important notices and warnings. It states that these regulators provide no automatic shut-off in the event of failure. Additionally, it cautions that at supply pressures exceeding 2 psi, the system must be rated for such pressures or protected by other means. Users are directed to consult Maxitrol’s Safety Warning Instructions (GPRMIEN.ES) for comprehensive safety guidance. Technical support is available from a Maxitrol Technical Support Representative.
Spring Ranges
The documentation provides limited information regarding spring ranges. The 325-3(B) model is listed with an inlet pressure of 2 psi (13.8 kPa) and 5 psi (34.5 kPa). Further details on spring selection are referenced in a Spring Selection Chart, but the chart itself is not included in the provided documentation.
Additional Considerations
The documentation references a Table of Contents that includes sections on Pressure Drop, Capacities, Dimensions, Sizing Instructions, and a Spring Selection Chart. However, only limited information from these sections is provided within the source materials. The documentation also notes that the largest single appliance served by the regulator should not exceed the maximum individual load specified for the model.
Conclusion
The Maxitrol 325 Series appliance pressure regulators offer a range of options for residential, commercial, and industrial gas applications. Proper installation, adhering to the specified mounting positions and venting requirements, is paramount for safe and reliable operation. Understanding the model-specific specifications, including inlet pressure, capacity, and emergency exposure limits, is crucial for selecting the appropriate regulator for a given application. Users should always consult the Maxitrol Safety Warning Instructions (GPRMIEN.ES) for complete safety information and technical support.