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Installing a Jackshaft Garage Door Opener

by Lorenz Prem
published on October 11 2009 6:56 pm

I decided to install a garage door opener on the new doors I installed earlier this summer. A conventional garage door opener cannot be installed in my garage. A beam sits right in the path of the track.

Liftmaster 3800

I did some research and found the Liftmaster 3800 jackshaft opener (on Amazon). These openers are installed on the side of the door instead of above the door. The Liftmaster and the Wayne Dalton appears to be the only residential models on sale in the US today.

LiftMaster Elite Series
LiftMaster 8500 (new)$359.00
LiftMaster 3800$395.25
LiftMaster 3900$459.68

Jackshaft garage door openers can only be installed on doors equipped with torsion springs. The opener sits at the end of the torsion shaft or tube. To open the door the opener spins the shaft. Conventional openers pull the door open through an extra connection in the center of the door.

Official Liftmaster installation Video

Instructions

Despite the number of chapters of the installation video, installation of the Liftmaster 3800 is a relatively simple task. There were no surprises, except for the problem with the cable tension sensor I'll get into later. It's one of those products where the install has been thought through.

The Motor

Begin by installing the motor unit on the torsion shaft. Simply lift it in place. The unit will "hang" on the bar making it easy to drill a few holes for the mounting plate. Screw the plate onto the motor and drive a few carriage bolt through the plate into the framing. That's it for the opener. Most of the work is in installing the sensors and the control unit.

The Control Panel

The unit comes with a hardwired control panel. The panel must be connected to the opener for the unit to function. Locate a good place for the panel and connect it to the opener using the provided two pole wire.

Safety Sensor

Like conventional openers the Liftmaster has a light beam running across the bottom of the door. When the beam is broken, the door will not close. In my case the two beam assemblies directly clipped onto the door rails. No fasteners required. Running the wire to the opener took more time than attaching the sensors. This is very good design, to say the least.

Automatic Lock

The automatic door lock took a bit more time to install. Unlike conventional openers, a jackshaft opener cannot keep the door closed when someone is trying to open it from the outside. It cannot push down.

To prevent unauthorized access, the Liftmaster comes with an automated latch that mounts on one of the rails. When the door is closed the control unit locks the door. A bolt protrudes through the rail and into the path of the door. When someone tries to open the door, one of the rolls catches the bolt blocking any movement. Installing the lock is a matter of drilling a few holes and connecting the lock assembly with screws.

Cable Tensioner

The last of the safety devices is the cable tension monitor. This device is a latch riding on one of the doors wires. If there is enough slack in the wire the latch closes and lets the opener know that there is no cable tension. The unit reverses and opens the door (reels in all the cable until there is tension again) This is important to prevent a certain type of accident.

In my case there was not enough space to mount the tensioner. Either the door or the torsion spring would come into contact with it during the cycle. I had to cut the mounting brackets off the tensioner and install it a bit out of square. The tensioner functions properly now.

Finish Up

At this point you are done. Program the door and enjoy the convenience of having an opener. I spent an hour cycling the door, just because... As I mentioned earlier, I installed a jackshaft opener because I had no space for a conventional one.

Now that I know how it works, I would never want to go back to a conventional opener. The jackshaft opener is very quiet. All it does is spin the torsion bar. There is no chain, belt, and carriage to make noise. It's also super easy to install and does not take up any room above the door. The doors opens just like it should.

Manufacturer's site: http://www.liftmaster.com

About the Author
"Lorenz is the founder of Hingmy. When he is not reviewing power tools or improving the site, he is building things in his workshop or playing hockey."