Potter Amseco WLS Tank Water Level Switch

The Potter Amseco WLS is a float-operated fire sprinkler tank water level supervisory switch with separate high- and low-level SPDT Form C contacts and a NEMA 4/IP54 weather-resistant enclosure. Designed for gravity and pressure water supply tanks, it detects water level changes before a 3-inch rise or fall and supports tank pressures up to 175 PSI. The WLS features 15A contacts rated at 125/250 VAC, a 1-1/2-inch NPT mounting connection, tamper-resistant cover screws, and compatibility with steel or wood tanks using appropriate mounting adapters.

Potter WLS Tank Water Level Supervisory Switch with Dual SPDT Contacts

The Potter Amseco WLS is a float-operated water level supervisory switch designed to monitor high and low water levels in fire sprinkler supply tanks. Manufactured by Potter Electric Signal Company, the WLS provides mechanical monitoring of water level changes in gravity-fed and pressurized sprinkler water storage tanks. Its internal float and actuating rod operate two independent single-pole, double-throw (SPDT) Form C switches, with one contact set dedicated to high water level monitoring and the other to low water level monitoring. The device detects changes in the water supply that could indicate an abnormal tank condition requiring investigation or corrective action. Designed for integration with compatible fire alarm supervisory circuits, the WLS supports commercial, industrial, institutional, and municipal fire protection installations where maintaining an adequate sprinkler water supply is essential.

The Potter WLS is engineered to detect water level changes before a 3-inch (76 mm) rise or a 3-inch (76 mm) fall in a pressure tank, supporting water supply supervision requirements referenced in NFPA 72. The two independent SPDT Form C switch contacts are rated at 15 amps at 125/250 VAC, 0.5 amps at 125 VDC, and 0.25 amps at 250 VDC, providing flexibility for connection to appropriately rated supervisory circuits and compatible external monitoring equipment. The high-water and low-water contacts can be monitored separately, allowing the connected fire alarm system to distinguish between abnormal water level conditions. Because the WLS uses a mechanical float-actuated switching mechanism, it does not require a separate electrical power supply for water level detection. The connected supervisory circuit monitors changes in contact position as the float rises or falls with the tank water level. The switch assembly is rated for a maximum tank pressure of 175 PSI (12.1 bar), making it suitable for properly designed gravity and pressure tank applications.

The WLS features a 1-1/2-inch NPT threaded mounting connection for installation in steel sprinkler supply tanks, with optional adapters available for alternate tank construction and existing mounting flanges. For steel gravity tanks, Potter specifies installing a compatible 1-1/2-inch threaded flange approximately 9 inches (229 mm) below the required water level. Pressure tank installations position the mounting flange at the required water level and use both high- and low-level supervisory contacts. For existing steel tanks equipped with a 2-inch threaded flange, the optional Potter 5020126 reducer bushing adapts the installation to the WLS mounting connection. Wooden gravity tanks require the separately available Potter 5180199 brass buttress-thread adapter, while optional mounting components include the 6660225 forged-steel flange, 6660083 bronze buttress nut, and 5330025 neoprene gasket. The unit must be installed vertically with the electrical conduit entrance oriented toward the bottom of the tank to maintain proper float movement and switching operation.

The Potter WLS incorporates a NEMA 4/IP54-rated enclosure suitable for indoor and outdoor installations when the factory-installed gasket and appropriate conduit fittings are used. Its housing features a weather-, UV-, and flame-resistant high-impact composite cover with a zinc-plated steel base, providing environmental protection for the internal electrical contacts and mechanical switch assembly. The enclosure measures 5.56 inches high, 3.50 inches wide, and 2.56 inches deep (141 x 89 x 65 mm) and weighs approximately 3.25 lbs (1.47 kg). The device operates in ambient temperatures from 40 F to 140 F (4.5 C to 60 C) and includes two tamper-resistant cover screws that require a supplied special key for removal. The WLS is designed for fire sprinkler water storage tank supervision in commercial buildings, warehouses, industrial facilities, institutional properties, and other locations using gravity or pressure tanks. For gravity tank installations, the high-water supervisory contact is not required, allowing installers to configure the device for low-level monitoring only when appropriate. Identified by Potter manufacturer stock number 1010117, the WLS provides dedicated mechanical water level supervision and is backed by a five-year manufacturer warranty. Its separate high- and low-level contacts, weather-resistant construction, and adaptable mounting options make it a practical solution for monitoring fire protection water supplies in accordance with applicable system design and inspection requirements.