Watts 0182421 Dual Switch

The Watts 0182421 is a professional-grade Dual Switch Assembly designed for Low Water Cut-Off (LWCO) applications in hydronic systems and steam heating boilers. Engineered as a complete one-piece unit under the SAN50D series, this assembly is the primary service solution for technicians maintaining Watts Series N50 and N501D units. As a direct replacement float and switch, it allows for rapid field servicing without disturbing existing piping or factory adjustments. This boiler water level control features a dual-switch configuration: the first switch triggers a low-water alarm for early detection, while the second switch serves as a high-limit safety to shut down the burner or compressor at 3/8-inch below the waterline. This failsafe prevent dry firing and critical equipment failure.

Rated for a maximum boiler pressure of 50 PSI and temperatures up to 250°F, the 0182421 ensures the HVAC safety switch architecture remains up to date with the latest SAN50D technical specifications. The bronze body and heavy-duty bellows construction provide the durability required for industrial HVACR environments and high-cycle commercial boilers. This assembly is identical to part number 182421 and serves as the standard replacement for legacy N50D dual switch models.

• Universal Compatibility: Fully interchangeable with all older Watts Series N50 and N501D low water cut-offs for seamless inventory management.
• Enhanced Safety: The dual switch assembly provides both an independent alarm circuit and burner cut-off to prevent dry firing.
• Ease of Installation: The one-piece design integrates the float and switch mechanism to simplify boiler maintenance and reduce downtime.
• High Pressure Rating: Specifically calibrated for systems with a maximum working pressure of 50 PSI, suitable for hot water space heating.

Is the Watts 0182421 compatible with older N50 valves?
Yes, the SAN50D is designed to be backwards compatible and interchangeable with all previous N50 and N501D series units, providing an easy path for low water cut-off servicing.

What is the difference between the SAN50D and SAN50S?
The SAN50D (0182421) includes a dual switch assembly for alarm and burner control, whereas the SAN50S is a single-switch model typically used only for burner shutdown.

Can this unit be used for steam applications?
While often utilized in hydronic systems, this LWCO switch is rated for 50 PSI maximum pressure; always verify that your specific steam pressure does not exceed this limit before installation.

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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.