LiftMaster 3840 Support Question
LiftMaster 3840 Support Question
Find answers below for this question about LiftMaster 3840.Need a LiftMaster 3840 manual? We have 1 online manual for this item!
Question posted by jmbfoto on July 30th, 2014
Door Will Not Close!
When I press the button to close door, it goes down a couple inches and then reverses and goes back up. The only way to close the door is to hold your finger on the button. I've tried re-aligning sensors, checking the wiring, and making sure there is nothing obstructing the door itself.
Current Answers
Related LiftMaster 3840 Manual Pages
3840 Manual - Page 1
... read this manual and the enclosed safety materials carefully! ■ Fasten the manual near the garage door after installation. ■ The door WILL NOT CLOSE unless the Protector System® is connected
and properly aligned. ■ Periodic checks of the opener are required to ensure safe operation. ■ The model number label is located under the light...
3840 Manual - Page 8
... 2x4 into masonry. • NEVER try to the highest point of Garage Door
2x4
OPTIONAL CEILING MOUNT FOR HEADER BRACKET
Structural Supports
Level (optional)
Installation procedures vary according to garage door types. Open your door.
1. This height will provide travel as shown here and on header wall or ceiling, otherwise garage door might not reverse when required.
You can attach...
3840 Manual - Page 11
... cm) above garage floor.
Safety Reversing Sensor 6" (15 cm) max. If it is closing .
above floor
11 The sending eye (with an amber indicator light) transmits an invisible light beam to clip onto the track of the door as long as the wall framing. The units must be connected and aligned correctly before the garage door opener will flash...
3840 Manual - Page 16
... is recommended to operate or play with the Safety Reversing Sensor wires along the top of the bell wires. Strip 7/16"
2-Conductor Bell Wire
Push Bar
Quick-Connect Terminals
(11 mm) of insulation from moving parts of closing garage door:
• Install door control within sight of door, at lower temperatures although the door control remains fully functional. To prevent possible...
3840 Manual - Page 17
...open door falling rapidly and/or unexpectedly. • NEVER use emergency release handle unless garage doorway is clear of the outer trolley.
• Adjust rope length so the handle is 6 feet (1.83 m) above the floor. Then the lights will turn OFF.
• Reverse... wires from motor unit to pull door open or closed. Battery Battery Cover
INSTALLATION STEP 9
Install the Lights
• Press ...
3840 Manual - Page 18
...light will not close. To reduce the risk of alignment or obstruction. TROUBLESHOOTING THE SAFETY REVERSING SENSORS 1. To avoid installation difficulties, do not run the opener at opener connections. • Incorrect wiring between sensors and opener. • A broken wire. 2. If the sending eye indicator light does not glow steadily
after installation, check for an open , it receives the...
3840 Manual - Page 21
... shown in Figures 1, 2 and 3. Trolley will re-engage automatically when opener is fully closed. SECTIONAL DOORS ONLY
Make sure garage door is operated. Proceed to outer trolley with a ring fastener.
• Fasten curved section to the door bracket in straight arm, disconnect straight arm.
Figure 3, Hole alignment alternative:
• If holes in curved arm are above holes...
3840 Manual - Page 22
... section to the longest possible length (with a 2 or 3 hole overlap).
• Make sure the garage door is being opened or closed .
See Figure 5.
• Connect the curved door arm section to the trolley using the 5/16"x1-1/4" clevis pin and ring fastener.
• When setting the up limit on the emergency release handle ...
3840 Manual - Page 23
Press and hold the purple button until the door reaches the desired UP (open door provides adequate clearance. NOTE: Make sure the door opens high enough for a binding or sticking garage door.
• After ANY adjustments are made, the safety reversal system MUST be too much pressure on the door, you may toggle the door back and forth using the black and purple buttons. Immediately...
3840 Manual - Page 24
... ANY adjustments are made, the safety reversal system
MUST be SERIOUSLY INJURED or KILLED by a closing garage door. • Too much force on garage door will interfere with 1-1/2" (3.8 cm) high object (or 2x4 laid flat) on contact with proper
operation of force required to open and close the door fully, inspect the door to enter unit into the Force Adjustment...
3840 Manual - Page 25
... or buckling of the garage floor. • Any repair to or adjustment of the door.
• Press the remote control push button to close from a remote if the indicator light in either sensor is off (alerting you to fail the Safety Reverse Test, call for a trained door systems technician. If the opener closes the door when the safety reversing sensor is not traveling...
3840 Manual - Page 26
... when the Light feature on again.
26 ALL repairs to disengage trolley ONLY when garage door is 100 watts maximum. If obstructed while closing , the door will reverse. If fully open or closed . They will also turn on , then off , press and hold the light button for five seconds.
6.
To restore this feature may be turned off as follows: With...
3840 Manual - Page 27
... the contrast. If you disable the motion sensor when using the opener lights as working lights.
To activate, press and hold the Lock button again for 2 seconds. Using the Smart Control Panel®
THE SMART CONTROL PANEL®
Press the push bar to open and close the door. Press the button of these side buttons
to increment the hour or minute displayed...
3840 Manual - Page 28
...manually. If it is unbalanced or binding, call
a trained door systems technician. • Check to disengage trolley ONLY when garage door is CLOSED. See Adjustment Step 3. The lockout feature prevents
NOTICE
the trolley from a falling garage door:
• If possible, use handle to pull door open door falling rapidly and/or unexpectedly.
• NEVER use emergency release handle unless...
3840 Manual - Page 29
...Dispose of a button.
After the opener lights flash, release all buttons.
The Proximity Sensor may cause undesired operation. This allows the sensor to the remote control, the LED lights turn on a non-metallic surface. THERE ARE NO OTHER USER SERVICEABLE PARTS. With the door closed, press and hold the Light button on the Smart Control Panel®.
4. Press and hold the remote...
3840 Manual - Page 32
... and secure brackets. • Verify door track is programmed with jumper wire. If the sensor indicator lights do not glow steady.
• Inspect sensor wires for the sensors. If motor unit activates, replace door control wires. Diagnostics Located On Motor Unit
"Learn" Button LED or Diagnostic LED
"Learn" Button
Installed Safety Reversing
Sensor
Your garage door opener is firmly secured to...
3840 Manual - Page 33
... receiving eye.
• Align sensors, if the indicator lights glow replace the wires for more than one second.
Meaning: This message will appear if the Safety Reversing Sensors are out of the opener:
Message
SAFETY SENSORS CHECK ALIGNMENT, BLOCKAGE OR MISWIRING. Meaning: This message will appear when the Prog button has been pressed on the door control. Meaning: This message...
3840 Manual - Page 34
... will be programmed to operate other Security✚® garage door openers.
34 Within 30 seconds, press and hold the "learn indicator light goes out (approximately 6 seconds). Press and release the "learn" button on any unwanted remote, first erase all codes:
Press and hold the button on motor unit until the learn " button on the hand-held remote* that technical measure. If...
3840 Manual - Page 35
... hours (up to a certain number of times this feature press and hold buttons 1 and 9 for your choice on the keypad. One Button Close: Opener can be used up one person without using a ladder. 1. To activate or deactivate this temporary PIN will no longer open the door.
Then press and hold the # button.
LOCK
LIGHT
3. It has learned the code.
To set...
3840 Manual - Page 36
...DESCRIPTION Smart Control Panel®
2 373P
3-Button remote control
3 10A19
3V2016 Lithium battery: LED and opener
7 6
4 10A33
8
5 29C151
3V2450 Lithium battery: proximity switch Remote control visor clip
6 41A2828
Emergency release rope and handle
NOTICE
assembly
11
7 41B4494-1 2-Conductor bell wire, white & white/red
8 41A5047
Door bracket w/clevis pin & fastener
CEILING MOUNT...
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