jackshaft opener question

[bpcobra]

I need a jackshaft opener for a high lift 8x16 wooden door. The horizontal rails are about 11 feet off the ground. The vertical section is about 9 feet high. The ceiling is vaulted so there is a 4 foot long, 25 degree sloped up rail between the vertical and horizontal sections. The door is supposed to weigh just under 700 lbs.

To lift the door by hand it takes a maximum of about 50 pounds of force to get it all the way up.

The installer is saying the Liftmaster 8500 is inadequate for the application and says a commercial opener is required. He hasn't given a good reason for that statement though. Has anybody else successfully installed a residential opener in a similar setup? Any recommendations on openers?

 

[tdkkart]

I think the Liftmasters specify "up to 140sq/ft door", ie:14x10,12x12 etc.

The other determining is making sure the springs are set correctly. In most cases, this means that if you open the door to the halfway point it should remain stationary, neither raising or dropping on it's own.

A phone call should answer your question.

 

[bpcobra]

The square footage of the door should have nothing to do with how well it can open. It should be the how well the door is balanced since the opener has to make up the difference between the weight of the door and the spring force.

The door will remain up and there is a spot where it stop in the middle. It is most definitely not a constant force to lift.

I've called 4 times and asked 4 different tech support people. Nobody can give me a straight answer. I just hear it weighs more than 650 pounds so therefore it won't work.

 

[JakeKohl]

50 lbs is too much for the 8500 to handle. I can attest for that. My springs were just a little out of adjustment on one of my doors and the opener wouldn't work reliably. It was considerably less than 50 lbs required to lift the door. I had to put a turn on each of the two springs for it to work properly.

 

[bpcobra]

What about using an additional set of gears such as the sheet door set for the 3950? That would give a good increase in lifting force.

 

[Dcampbell98xj]

Liftmaster makes a medium duty commercial jack shaft opener. It's not as fancy and stylish but it's more then enough to lift a door that size. Remotes and keypads will work with it but there is no battery back up feature. http://www.liftmaster.com/lmcv2/productdetail/1689/medium-duty-jackshaft-operator/

 

[bpcobra]

It wouldn't be cobbled together. It would be an off the shelf setup which comes with an extra gear reduction set for more torque at the jackshaft.

I think that the Liftmaster MJ is going to be the way to go which is what Liftmaster customer support also recommended. I have reservations about using a commercial opener, but I think I have to get over it. Thanks Dcampbell.

 

[jstroede]

I have reservations about using a commercial opener, but I think I have to get over it. Thanks Dcampbell.

Why if I may ask?

John

 

[bpcobra]

1. Lack of reversing if the door hits an obstruction. It only reverses if the light is tripped or it can be set up with a pressure sensitive strip under the door, but not both. I think the light is more beneficial since I'd rather avoid hitting a person or car than reverse after contact.

2. Hassle passing inspections if we resell the house.

Why if I may ask?

John

 

[wildbill23c]

If it takes some considerable force to lift a garage door by hand, your door springs are either incorrect, or they aren't adjusted properly. It shouldn't require 50lbs of force to open any garage door regardless of what it weighs. Something tells me your springs aren't wound properly.

Test your door by opening it about 1/2 way and letting go. Given your amount of force required to open the door it will probably try and close on its own. If that's the case you need to have someone re-wind the door springs, you can do it yourself, but be extremely careful, and DO NOT get any parts of your body around those springs while you are winding them. Unless you know what you are doing call a door installer and have them adjust the springs and get the door within specifications. When I was installing garage doors, all of mine were set, so that a small child could open the door by themselves. My boss always said, that the door should be able to be easily opened by grandma. Anything more than that, the door is actually out of adjustment and a 50lb lift requirement is not close to specs. There are dozens of spring sets for different size and weight doors, I'd call a door installer and have them come out and inspect the springs, and adjust or replace them if needed.

No, that opener will not work on that door because of the lift load that is currently on it. You need to drop that load considerably for that opener, or any opener for that matter to properly work. All the opener would do if it was installed is attempt to open the door overload and reverse itself. It would never work properly and would never be reliable.

Once the door is properly adjusted to open manually with very little effort, then you could get away with your Liftmaster 8500 just fine.

 

[jstroede]

You can use multiple safety devices with an MJ5011. The manual shows how to wire in CPS photo eyes with the sensing edge.

John