Home » LiftMaster » Garage Door Openers » LiftMaster 3950

LiftMaster 3950 Support Question

Find answers below for this question about LiftMaster 3950.
Need a LiftMaster 3950 manual? We have 2 online manuals for this item!

LiftMaster Overview Questions Manuals Reviews Videos Research

Question posted by jgrowlett on August 27th, 2012

What Size Shaft Does The Live Sprocket Fit On Door?

The person who posted this question about this LiftMaster product did not include a detailed explanation. Please use the "Request More Information" button to the right if more details would help you to answer this question.

I Know the Answer!

I have the same question
Request More Information

Current Answers

There are currently no answers that have been posted for this question.
Be the first to post an answer!

Remember that you can earn up to 1,100 points for every answer you submit. The better the quality of your answer, the better chance it has to be accepted.

Related LiftMaster 3950 Manual Pages

3950 Addendum Manual - Page 1

... supplier. The axle is important to identify the door type before attempting an installation of the Model 3950 door operator. ADDENDUM DOOR COMPATIBILITY FOR MODEL 3950 IMPORTANT INSTALLATION INSTRUCTIONS It is locked in place while the door opens and closes. Door Type Identiﬁcation Dead Shaft Door MOUNTING OPTIONS: 1 Standard wall mount using the brackets included with the drum...

3950 Addendum Manual - Page 2

... for mounting the door sprocket to the door axle which spans the drive sprocket and the door sprocket. If inside mounted, minimum of shaft is required (2.5" recommended) for "Wall" dimension is required to the outside of side room depends on the mounting option for the Model 3950. The assembly is attached to the Live Door Shaft. (Figure 3) 2 The door sprocket is held up...

3950 Addendum Manual - Page 3

... the 2.25" from center, 3 equally spaced hole pattern. Dead Shaft Door Construction Spring Clearance The Model 3950 requires that an extra drum (Figure 4 - 2nd Drum) is added on the end drum (Figure 4 ). Some door manufacturers require the door to be obstructed by sliding the sprocket on the door shaft to provide an unobstructed platform for Operator), so that...

3950 Addendum Manual - Page 4

The Model 3950 comes with a selection of spacing. 4 Drum Holes To Inspect For Obstruction Door Construction The Dead Shaft Door must not have more than a 2" inset from the curtain edge to provide a maximum 3" of spacers that can be present) 2.25" Figure 5 - Mounting Hole (PEM nut may be used in conjunction to the drum.

3950 Addendum Manual - Page 5

For a standard wall mount to the outside of the door opening, a minimum of side room depends on which the Model 3950 is required for the operator, however, the door brackets must not be bent or damaged in order for installation to the sprocket well and could derail the chain. Minimum Side Room The minimum amount of...

3950 Addendum Manual - Page 6

... MOUNT ALIGNMENTS Sprocket inner position 1" Sprocket middle position 1-3/8" Sprocket outer position 1-5/8" 6 OPERATOR DRIVE OPTIONS WHEN USING MODEL 3950MB MOUNTING BRACKET The operator drive sprocket can be attached in one of three positions when inside mounted or one of two positions if outside mounted that provide offset from the outer edge of the door guides: Refer...

3950 Manual - Page 1

® DOOR OPERATOR Model 3950 For Light Duty Commercial Use The Chamberlain Group, Inc. 845 Larch Avenue Elmhurst, Illinois 60126-1196 www.liftmaster.com Com patible with Owner's Manual ■ Please read this manual and the enclosed safety materials carefully! ■ The door WILL NOT CLOSE unless The Protector System® is connected and...

3950 Manual - Page 2

... safety instructions 6 Install the door sprocket 6 Mount the operator 7 Attach the emergency release rope and handle 8 Install the single button control station 8 Electrical requirements 9 Install The Protector System 10-12 Adjustment 13-15 Program the travel limits 13 Set the force 14 Test The Protector System 15 To open door manually 15 Operation 16...

3950 Manual - Page 3

... Door Height 12 feet Maximum Door Size 14 feet x 12 feet (not to be installed to the door manufacturer for more information. Specifications Volts 120 Vac - 60 Hz, ONLY Current 1.0 AMP Rated Load 325 in. If your door binds, sticks or is mounted below 6 feet (1.83 m). For live shaft type doors the drive shaft needs to extend 1-1/2" beyond the door...

3950 Manual - Page 4

...material. 2-Conductor Bell Wire White & White/Red Mounting Bracket (4) Operator Door Sprockets Safety Labels and Literature Hardware Inventory Installation Hardware Tubular Spacer 1/2" (6) Tubular...20 x 1/2" (2) Single Button Control Station Safety Reversing Sensor Bracket (2) 12 Tooth Drive Sprocket with Drive Chain The Protector System® (2) Safety Reversing Sensors (1 Sending Eye and ...

3950 Manual - Page 5

... purchase (see accessories). 1. Position two mounting brackets on your installation. Figure 1 Output Shaft Drive Sprocket Bolt Bolt ASSEMBLY STEP 2 Attach Mounting Brackets The operator can be mounted to the wall with the door sprocket. 1. Align the center holes in the drive sprocket with the hole in the alignment of the operator. 2. Finger tighten the bolts...

3950 Manual - Page 6

...above floor. 6. Live shaft type (Figure 1): 1. Slide the door sprocket onto the end of the door shaft. 2. Mark and drill a hole through bolt and nylock nut. An improperly balanced door may not reverse when required and could be made by a trained door systems technician BEFORE installing operator. 4. Figure 1 Door Door Shaft Through Bolt Door Sprocket Nylock Nut...

3950 Manual - Page 7

... are under EXTREME tension. • ALWAYS call a trained door systems technician if door binds, sticks or is parallel to door shaft and sprockets are not aligned, the drive sprocket can be fastened to wall using appropriate method and hardware (not provided). Live Shaft Chain Mounting Hardware (not provided) Dead Shaft Operator Chain Mounting Hardware (not provided) 7 Operator Secure...

3950 Manual - Page 8

... 132A2112-2 WARNING To prevent possible SERIOUS INJURY or DEATH from a falling door: • If possible, use emergency release handle unless doorway is no...open door falling rapidly and/or unexpectedly. • NEVER use emergency release handle to disengage door ONLY when door is not connected BEFORE installing door control. • Connect ONLY to prevent slipping. 2. DO NOT EXCEED 10 DOOR...

3950 Manual - Page 9

...5. To make it fit outlet. This plug will only fit into the outlet you have, contact a qualified electrician to establish permanent wiring connection. • Door installation and wiring MUST...to proper length and strip insulation. 7. Reinstall the cover. If the plug doesn't fit into a grounding type outlet. INSTALLATION STEP 5 Electrical Requirements To avoid installation difficulties,...

3950 Manual - Page 13

... by using the black and purple buttons to reach the desired closed position. 7. Press and hold the black button until the door reaches the desired UP (open) position. NOTE: Make sure the door opens high enough for your vehicle. 3. Figure 1 LED Black Button Without a properly installed safety reversal system, persons (particularly small children) could...

3950 Manual - Page 14

... travel through a complete cycle, up and down, in order for the force to close the door. 1. If the garage door opener cannot open and close the door (DOWN). Figure 1 LED Black Button Purple Button Figure 2 Push Purple button twice to enter into Force Adjustment Mode BLACK PURPLE Figure 3 14 The LED will ...

3950 Manual - Page 16

... fully. WARNING OPERATION IMPORTANT SAFETY INSTRUCTIONS WARNING To reduce the risk of children. ALWAYS keep door in sight until the door starts to adjust the garage door opener properly may not reverse when required and could result in the opening , the door will close. 5. ALWAYS keep remote controls out of reach of SEVERE INJURY or DEATH: 1. NO...

3950 Manual - Page 17

... the operator should be able to the door shaft, sprocket and chain are off. • Remove the bell wire from the door control terminals and operate from the remote control... are the springs broken? HAVING A PROBLEM? (TROUBLESHOOTING) 1. The door doesn't open completely: • Is something obstructing the door? See Installation Step 6. • See Adjustment Step 2. Repeat safety...

3950 Manual - Page 21

DESCRIPTION 6 41A5266-1 Safety reversing sensor brackets (2) 7 41A7279 Live shaft sprocket kit 8 41A7280 Dead shaft sprocket kit 9 41A7278 12 tooth sprocket kit 10 41A7314 Drive chain (#48) NOT SHOWN 114A4066 Owner's manual Motor Unit Assembly Parts 5 2 1 3 4 KEY PART NO. DESCRIPTION 1 APBS 1 Single button control station 2 41A6298-5 ...