LiftMaster 3840 3840 Manual - Page 18
Installation Step 11, Installation Step 12
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INSTALLATION STEP 11 Electrical Requirements To avoid installation difficulties, do not run the opener at this time. To reduce the risk of electric shock, your garage door opener has a grounding type plug with a third grounding pin. This plug will only fit into a grounding type outlet. If the plug doesn't fit into the outlet you have, contact a qualified electrician to install the proper outlet. To prevent possible SERIOUS INJURY or DEATH from electrocution or fire: • Be sure power is not connected to the opener, and disconnect power to circuit BEFORE removing cover to establish permanent wiring connection. • Garage door installation and wiring MUST be in compliance with ALL local electrical and building codes. • NEVER use an extension cord, 2-wire adapter, or change plug in ANY way to make it fit outlet. Be sure the opener is grounded. RIGHT WRONG PERMANENT WIRING CONNECTION If permanent wiring is required by your local code, refer to the following procedure. To make a permanent connection through the 7/8" hole in the top of the motor unit (according to local code): • Remove the motor unit cover screws and set the cover aside. • Remove the attached green ground terminal. • Cut black and white wires and strip away 1/2" (1 cm) of insulation, 3" (7.5 cm) before spade terminals. • Remove the power cord from opener. • Install a conduit or flex cable adapter to the 7/8" hole. • Run wires through conduit, cut to proper length and strip insulation. • Attach with wire nuts provided. Attach the ground wire to the green ground screw. The opener must be grounded. • Properly secure wire under plastic ties so that wire does not come in contact with moving parts. • Reinstall the cover. To avoid installation difficulties, do not run the opener at this time. Black Wire Wire Nuts Ground Tab Ground Wire Green Ground Screw White Wire INSTALLATION STEP 12 Complete Safety Reversing Sensor Installation ALIGNING THE SAFETY REVERSING SENSORS Plug in the opener. The indicator lights in both the sending and receiving eyes will glow steadily if wiring connections and alignment are correct. The sending eye amber indicator light will glow regardless of alignment or obstruction. If the green indicator light in the receiving eye is off, dim, or flickering (and the invisible light beam path is not obstructed), alignment is required. • Loosen the sending eye wing nut and readjust, aiming directly at the receiving eye. Lock in place. • Loosen the receiving eye wing nut and adjust the sensor vertically and/or horizontally until it receives the sender's beam. When the green indicator light glows steadily, tighten the wing nut. TROUBLESHOOTING THE SAFETY REVERSING SENSORS 1. If the sending eye indicator light does not glow steadily after installation, check for: • Electric power to the opener. • A short in the white or white/black wires. These can occur at staples, or at opener connections. • Incorrect wiring between sensors and opener. • A broken wire. 2. If the sending eye indicator light glows steadily but the receiving eye indicator light doesn't: • Check alignment. • Check for an open wire to the receiving eye. 3. If the receiving eye indicator light is dim, realign either sensor. NOTE: When the invisible beam path is obstructed or misaligned while the door is closing, the door will reverse. If the door is already open, it will not close. The opener lights will blink 10 times (if bulbs are not installed, 10 clicks can be heard). See page 11. 18