STI STI-3150CR Weather Stopper Protective Cover

Overview

The STI-3150CR is a clear polycarbonate protective enclosure designed to guard manual fire pull stations against accidental and intentional false activations while permitting legitimate emergency access. Operating at 9VDC when a horn is added (standard units are battery-powered; see Compatibility), this unit includes a custom-label faceplate and integral spacer for frame mounting. The closed-cell gasket design handles outdoor exposure without degrading seal performance—critical for sites where pull stations face rain, temperature swings (-40°F to 250°F), and UV exposure. Unlike simple guards that slow response time, the Stopper II mechanism is designed to maintain rapid legitimate alarm triggering while raising the friction cost of false pulls.

Compatibility

The STI-3150CR fits standard manual pull station openings and accommodates larger or surface-mounted stations when paired with the optional STI-3100 conduit spacer (included in this SKU). The 9VDC specification applies only to models equipped with the piezo horn option; standard battery-powered units do not require external voltage. Verify your pull station geometry and frame depth before ordering—the spacer is fixed, not adjustable. If your installation uses a remote-powered horn variant, confirm 9VDC availability from your existing panel or UPS system; no step-down transformer is needed.

Installation Notes

When covering an outdoor pull station, UL requires the station itself to be listed for outdoor use—the cover does not upgrade an indoor-rated station to outdoor duty. Mount the spacer flush to the frame and verify gasket compression around all edges to maintain weather resistance. The polycarbonate is rated for normal use (no deliberate impact testing); avoid mounting directly where it faces routine bumping or vibration. Ensure 9VDC power runs on a dedicated circuit if the horn is activated by the same control panel as the alarm—horn draw can spike during pull events.