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Fisher Type 749B | High-Capacity Automatic Changeover Manifold

The Fisher Type 749B is a heavy-duty automatic changeover manifold designed for high-demand commercial and industrial LP-Gas systems. This assembly ensures a continuous, uninterrupted gas supply by automatically switching from an exhausted supply cylinder to a reserve cylinder once the pressure in the primary source drops below a specific threshold. Engineered for reliability in mission-critical applications, the 749B eliminates the need for manual intervention and prevents costly downtime caused by fuel depletion.
Brand: Fisher
Availability: In Stock
Origin: China

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Key Benefits and Advantages

  • Uninterrupted Gas Supply: The primary function of the 749B is to maintain flow during source transitions. When the “service” side of the manifold is depleted, the internal mechanism shifts the load to the “reserve” side seamlessly, ensuring that boilers, furnaces, and industrial burners continue to operate without pilot outages.

  • Large Capacity for Industrial Demands: Unlike residential changeover units, the 749B is built for high-volume service. By utilizing two 64 Series regulators as the core components, this assembly can manage the heavy flow requirements typical of large commercial kitchens, agricultural dryers, and manufacturing facilities.

  • Visual Status Monitoring: Every 749B assembly includes a Type 803 direct indicator. This visual gauge provides a clear, color-coded signal to facility managers or gas delivery personnel, indicating whether the system is drawing from the primary source or has already switched to the reserve.

  • UL Listed Safety: The Type 749B manifold is Underwriters Laboratories (UL) listed, ensuring it meets rigorous safety and performance standards for LP-Gas equipment. (Note: Second-stage regulators used in conjunction with this manifold are listed separately).

  • Flexible System Integration: The assembly is designed to work as the primary pressure reduction stage in a multi-stage system. It is most commonly used in tandem with a Type HSRL or 64SR second-stage regulator to provide the final delivery pressure to the building or equipment.

  • Rugged Construction: Built to withstand the stresses of manifold service, the components are made from high-strength materials that offer excellent resistance to the elements and the chemical properties of LP-Gas.

Technical Properties

  • Operation: Automatic changeover.

  • Configuration: Dual 64 Series regulators with a Type 803 indicator.

  • Capacity: Engineered for large-scale commercial/industrial BTU loads.

  • Media: LP-Gas (Propane).

  • Application: First-stage pressure reduction in a two-stage system.

  • Indicators: Direct visual indication of supply status (Service/Reserve).

Field of Application

The Type 749B is the industrial standard for any facility where a gas outage would result in significant operational or financial loss.

Primary Industries and Uses:
  • Commercial Laundries and Kitchens: Ensuring continuous fuel for large-scale dryers, ovens, and steam generators.

  • Agricultural Operations: Providing a reliable gas source for grain drying and livestock heating systems during peak seasons.

  • Hospitality and Hospitals: Maintaining backup gas supply for water heating and emergency generators.

  • Manufacturing Plants: Supplying constant fuel for heat-treatment furnaces and process heaters.

Specification

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Available Certificates

We provide comprehensive documentation support strictly mapped to your model codes. From standard Q4 (Calibration Certificate), Q8 (Material Traceability), and P1 (Hydrostatic Testing) to specialized Chamber of Commerce (COI) authentication, we ensure every detail meets your project’s compliance and traceability requirements.

FAQ

Q: Which brands and models do you offer?

A: We specialize in industrial automation instruments such as pressure transmitters and flow meters from brands like Rosemount, Yokogawa, and Micro Motion. Additionally, we can help source other related products globally based on your specific requirements.

A: We offer global shipping, covering Southeast Asia, the Middle East, Europe, South America, North America, and many other regions. Specific logistics solutions can be customized based on customer requirements.

A: The lead time for product delivery varies depending on the product type, quantity, and shipping method. Our sales team will provide you with an estimated delivery time frame based on your specific requirements.

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