Mallard Control Model 3900 Pneumatic Liquid Level Switch 3900-10FS-SVRR-SM 1" FNPT Falling Level

The Mallard Control Model 3900 is a robust pneumatic snap-acting liquid level switch designed for reliable detection and control of liquid levels in industrial applications such as oil and gas production, chemical processing, and water treatment systems. This specific configuration, 3900-10FS-SVRR-SM, features a 1" FNPT process connection and is optimized for falling level detection, providing a snap-action response to changes in liquid levels. It operates without electricity, making it ideal for hazardous or remote environments where pneumatic systems are preferred. Key benefits include high reliability, corrosion-resistant materials, and easy maintenance with field-reversible action from rising to falling levels. Compared to electronic level switches, the Model 3900 offers advantages in explosion-proof settings and lower long-term costs due to its simple mechanical design, though it may require pneumatic supply infrastructure, which could be a drawback in non-pneumatic setups. The unit includes dual pressure gauges for monitoring supply and output pressures, ensuring precise operation. With its durable construction, it handles pressures up to 1500 psi and temperatures from -20°F to 400°F, depending on materials. This new unit comes with original documentation, making it suitable for immediate installation in tanks, vessels, or scrubbers for overfill protection or pump control.