HVAC Duct Detector Installation

Remove the paper from the seal-adhesive template that comes with a duct detector. Press the template against an area of the ductwork that is accessible and sits 24 to 30 inches away from duct fittings, branch lines or elbows.

Secure a 1 1/4-inch hole saw in the chuck of a drill motor. Drill one hole at each location marked on the template. Drill slowly to avoid binding the teeth of the saw in the sheet metal of the duct. Push the end of a tape measure into one 1 1/4-inch hole. Continue pushing until the tape measure contacts the other side of the duct.

Cut a piece of sampling tube to the measured length with hacksaw. Ensure the cut is square. Slide the end of the sampling tube in the intake port of the duct detector. Rotate the tube to aim the line of intake holes with the front side of the detector. Push the supplied exhaust tube in the exhaust port in the detector's exhaust port. Tighten each holding screw -- preset at the base of each port -- with a Phillips screwdriver.

Remove the paper backing from the two supplied foam washers. Drop one washer over the intact tube and one over the exhaust tube. Press the washers firmly against the detector body. Align both tubes with the 1 1/4-inch holes. Push the detector tight to the side of the duct. Secure a 3/32-inch drill bit in the drill motor. Drill a hole at each mounting hole in the detector body. Run one supplied mounting screw through each 3/32-inch hole with the Phillips screwdriver.

Remove the screws holding the clear cover to the detector by turning them counterclockwise with the Phillips screwdriver. Pull the cover off the body and set it aside.

Cut 3-inches of insulation from one end of a Romex cable by sliding the blade of a utility knife along its center and around its circumference. Pull the insulation off the end of the cable. Strip 1/2 inch of insulation from the end of each wire with a sire stripper. Push the exposed wires through the cable hole. Tighten the cable clamp located inside the entry hole with a flathead screwdriver.

Stretch the cable 12 inches past the nearest available junction box or subpanel.

Turn off the breaker to the power source. Remove the cover plate from the junction box or subpanel. Remove the outer cable insulation as described in step 6. Strip 1/2-inch of insulation from the end of each wire. Strip 1/2-inch of insulation from the end of each of the house wires in the power source. Match the wires from the cable to the corresponding house wire. Put the ends of the like wires together. Thread a wire nut onto the end of each set of paired wires. Replace the panel or box cover.

Refer to the detector installation manual to determine the correct wire configurations for your specific application. Slide the end of each wire into the correct power terminal of the duct detector. Turn each terminal screw clockwise with a flathead screwdriver.

Slide the clear cover onto the detector body. Tighten each mounting screw with the flathead screwdriver.