STI STI-TSTAT520F Thermostat Heater Control Module

Overview

The STI-TSTAT520F is a 9VDC thermostat-controlled heater module used to condition the interior of protective enclosures mounted outdoors, keeping call points, sounders, and other enclosed hardware within their operating temperature range through cold and damp conditions. It fits inside weather-rated housings deployed on exterior walls, loading docks, and other unconditioned locations where condensation and low temperatures threaten reliable device operation.

Compatibility

Built to install inside STI Stopper II and Weather Stopper II enclosures — the polycarbonate protective covers STI documents for the STI-1200, 1230, 1100, 1130, 1250, and 3150 device families. Confirm enclosure model before ordering, since fixing-hole spacing and cable entry points differ between the standard Stopper II and the larger Weather Stopper II frame.

Installation Notes

The Stopper II and Weather Stopper II frames it mounts inside are secured with four fixing screws into holes drilled with a 7mm masonry bit. Weather Stopper II installs require the weather gasket to be positioned over the protected device before the frame and screws go on, and unused cable entry holes on surface installs get blanked off with the spacer inserts — install the thermostat module before closing up the gasket and frame so wiring stays accessible. Runs on 9V DC; confirm available low-voltage supply at the enclosure before wiring.