Potter Amseco PTS-C Plug-type Supervisory Switch

The Potter PTS-C is a plug-type fire sprinkler valve supervisory switch with a sealed reed-switch mechanism, SPDT Form C supervisory contacts, and a NEMA 4/6P (IP67) weather-resistant enclosure. Designed for special applications involving non-rising stem gate valves, it uses an 8-foot waterproof cable that pulls a plug from the switch housing when the valve is operated. The PTS-C includes a separate cover tamper switch, operates from -40 F to 140 F, and is UL/cUL Listed and FM Approved. It is intended for installations where conventional valve supervision methods are impractical.

Potter PTS-C Plug-Type Fire Sprinkler Valve Supervisory Switch

The Potter PTS-C is a special-application plug-type supervisory switch designed to monitor fire sprinkler control valves, particularly non-rising stem gate valves where conventional valve position monitoring devices cannot be installed practically. Manufactured by Potter Electric Signal Company, the PTS-C uses a removable supervisory plug connected to an approximately 8-foot (2.43-meter) waterproof cable to identify valve operation. During installation, the cable is routed through the valve handwheel and adjusted so that movement toward the closed position removes the plug from its receptacle. Removing the plug changes the state of an internal sealed reed-switch contact, allowing a compatible fire alarm control panel or supervisory monitoring system to register a valve supervisory condition. The PTS-C can also monitor selected gates and other mechanical equipment where removal of a secured plug provides an appropriate indication of operation. Its specialized design supports commercial, industrial, institutional, and municipal fire protection installations containing unusual valve configurations that cannot accommodate standard supervisory switches.

The Potter PTS-C incorporates a single-pole, double-throw (SPDT) plug-operated supervisory contact and a separate SPDT enclosure tamper switch for monitoring both valve operation and unauthorized access to the switch housing. The plug supervisory contacts are rated at 100 mA at 28 VAC/DC or 250 mA at 12 VAC/DC, while the cover tamper contacts are rated at 250 mA at 28 VAC/DC. Its sealed reed-switch design minimizes exposure of the switching contacts to moisture, dirt, and other contaminants, helping reduce contact corrosion in demanding environments. The cover tamper mechanism activates when the enclosure cover is removed and can be wired into the same supervisory circuit as the plug contact or connected to a separate circuit for independent monitoring. Because the PTS-C operates through a mechanical plug and magnetic reed-switch arrangement, it does not require a separate electrical power supply to detect valve operation. The connected alarm or supervisory control panel provides the circuit supervision necessary to recognize changes in contact state. The unit includes tamper-resistant cover hardware and a special hex key required to access the plug receptacle for restoration.

The PTS-C features a non-corrosive composite enclosure rated NEMA 4 and NEMA 6P (IP67) when installed with suitable electrical fittings, providing environmental protection for indoor and outdoor applications. Its weather-resistant construction supports installation in sprinkler valve pits, wells, underground areas, and other locations where temporary flooding or moisture exposure may occur. The enclosure measures approximately 7 inches long, 3.75 inches wide, and 3 inches deep (177 x 95 x 76 mm), including the mounting bracket, and weighs approximately 13.6 ounces (386 grams). The device operates across an ambient temperature range of -40 F to 140 F (-40 C to 60 C). Installation involves securing the switch housing near the monitored valve, inserting the supervisory plug into its receptacle, and routing the supplied two-conductor, 18 AWG waterproof cable through the valve handwheel. The cable is adjusted so that closing the valve mechanically withdraws the plug, activating the supervisory contacts. The manufacturer specifies that no more than 2 inches (50 mm) of excess cable should remain inside the housing and that wiring must be routed away from the cover tamper mechanism. Once activated, the plug cannot be reinserted without opening the tamper-resistant receptacle cover using the supplied hex key.

The Potter PTS-C is designed for special fire sprinkler supervisory applications involving non-rising stem valves, difficult-to-monitor valve assemblies, and other installations where approved conventional supervisory methods are unavailable or impractical. The unit is UL and cUL Listed, FM Approved, California State Fire Marshal (CSFM) Listed, and accepted by the New York City Materials and Equipment Acceptance program (NYMEA) according to Potter's published product documentation. However, the manufacturer specifically identifies the PTS-C as a special-application supervisory device rather than a conventional NFPA-compliant automatic valve restoration monitor. Unlike standard valve supervisory switches that automatically return to their normal condition when a monitored valve is reopened, the PTS-C requires manual plug reinsertion after activation. Potter instructs users to verify that the valve is fully open before restoring the supervisory plug and emphasizes that the device should be selected only where another approved or listed valve supervision method is unavailable or impractical. The manufacturer recommends quarterly testing, or more frequent testing when required by the authority having jurisdiction, to verify correct switch operation and supervisory reporting. Identified by Potter stock number 1010201, the PTS-C provides a specialized monitoring solution for unusual sprinkler valve configurations that require a mechanically secured, tamper-resistant supervisory connection.