Original Storage Tank Equipment from Scully™

The first choice in independent electronic self-checking overfill prevention systems. Features Dynacheck® automatic and continuous Self-Checking® circuitry which monitors the control unit, wiring, connections, and sensors for faults 30 times per second for the ultimate in fail-safe protection. Longest-running safety record in the industry; over 25 years reliability and incident-free protection

ST-15-WX Overfill Prevention and Liquid Detection Monitor

Safe, reliable, high- and low-level warning and spill prevention system for storage tanks. The system incorporates Dynamic Self-Checking® circuitry which monitors the controller, wiring, connections, and sensors for faults 30 times per second for maximum safety. Sounds an audible alarm and/or controls pumps and valves for automatic shutdown when the sensors detect liquid or a fault in the system. As a high level warning and emergency shut-down system, it operates independently from your gauging system to ensure that inventory inaccuracies do not compromise the safety of your operation.


  • The WX System provides for the capability of alarms as well as controlling pumps and valves for immediate, automatic shutdown of product flow
  • Monitors from 3 –12 sensing points depending on model. Well suited for multiple fixed storage tank applications where individual display and/or output control is required.
  • Uses output sensors approved as intrinsically safe for use in Class I, Division 1, Group C, and D hazardous locations
  • Features NEMA 4 style watertight housings
  • Works in conjunction with either Scully field-proven thermistor or two-wire optic sensors

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Two-Wire Optic Sensor

Maximum safety with Dynacheck–automatic and continuous Self-Checking® circuitry when used with Scully monitoring systems. Field-proven, optic level-sensing technology with NPT mounting threads. SP-IO models are designed for use with Scully ST-15WX Control Monitors. Typical uses include storage tanks, double-containment piping trenches, and double-wall storage tank interstitial space monitoring. Years of dependable, virtually maintenance-free operation. Sensors can be easily extended to desired length at installation site using a 3/8” x 3/8” coupler and the required length of 3/8” NPT pipe


  • Reliable components with no moving parts
  • Functions within a wide range of temperatures and in a variety of liquid products
  • Sensors can be extended using a 38” x 3/8” coupler and the required length 3/8” NPT pipe.
  • Intrinsic safety approvals SIL 2 Capable with Scully ST-15WX System.