LiftMaster 3800 Questions

[Jeff F]

Couple of question about the LM 3800 openers. Lots of threads about them here, but if it's been answered before I can't find it.

I just installed a pair of these on 10H x 12W Amarr Classica 3000 doors.

1: When the doors were installed, the installers asked if I was going to put openers on them, and I told them yes. They wound the torsion spings pretty tight-- if I unlatch the door and pull up the slightest bit, they fly up, and I have to pull pretty hard to get them to go down. My guess is that they did this because it would be easier on a (regular) opener. Well, with the 3800s the door goes down kind of slow, especially at the top of the travel. Could this be because the spring has so much tension? Or does the 3800 pretty much have a fixed shaft speed regardless of load? I could have them come out and take some tension off, but I'm not sure if this would be wise, or fix anything.

2: Is it just me, or is it hard to mount the cable tension monitor in the way that they recommed? On my door, there is a metal angle that holds the door track and prevents it from being mounted on the outside of the door. I ended up with it mounted to the door header, inside the track, hinge down. Works fine (the door clears it on the way up... barely), except that it seems like if I ever tried to run the door all the way back on the track, it would exceed the travel of the sensor and yank it off. Seems like this would be a problem if it were on the outside too?

3. I haven't installed the remote lights yet, but before I decide where they go, I was trying to figure out if I could set them up so that BOTH lights went on when EITHER door was opened. I'm also considering wiring them up so that they just turn on the general overhead lights instead-- bascially just making it like another switch in parallel with the wall switch. Anyone done this? Also thinking that I could do this with one of the 395LM Remote Light Controls http://www.liftmaster.com/consumerweb/pages/accessoriesmodeldetail.aspx?modelId=839 but I still need it to respond to either opener. Thoughts?

 

[nova65ss]

They really shouldn't fly up but alot of guys set the springs a little strong knowing they are going to weaken a little over the 1st couple of months. If you have a 3800 you want to have them almost at a perfect balance not flying up and not falling down.

This is basically how you want it on the inside.

Problem is in this pic there is not a 2 x 6 jamb so you will need to add a small 2 x 6 to mount it to to make it flush with everything else. Not sure if this is what you were describing?

I have never done both lights to come on at the same time. It is easy to try though just press the learn button on the light and then press the button to make the op go up or down and then do it again for the other light. It may lose the 1st code and only remember the 2nd not sure?

 

[Jeff F]

Ah, that makes more sense now. Since this is a pole building, the header over the door doesn't have to be very tall-- there is a 6x6 post on either side of the door supporting the structure. The builders added built up "stanchions" at the ends and center to support the torsion spring, but there isn't anything else in that gap.

You can imagine what would happen if I tried to run the door all the way up the track-- the tension sensor would get to about 45 degrees, then it would try to yank it out. All I need to do is put a 2x4 stringer between the header and the ceiling, then flip the sensor over and swap the roller to the other side so the pivot is close to the drum, then I can get the door to go all the way up.

It is possible to program the light to both doors. In fact I programmed a light to go on with either door and also to go on with button 2 on the remote. Cool. My plan here is to wire it through a realy to the exterior lights, so I whenever I open the doors the exterior lights go on, and it also allows me to turn the exterior lights on/off seperately from the house via the remote.

 

[Cryptic1911]

I know I'm going to get yelled at by the real garage door guys, but you can eliminate the tension sensor assembly if you put a 1k ohm resistor into the two spring clips where the wires go into the motor assembly. both of mine are bypassed this way and work fine

 

[nova65ss]

I know I'm going to get yelled at by the real garage door guys, but you can eliminate the tension sensor assembly if you put a 1k ohm resistor into the two spring clips where the wires go into the motor assembly. both of mine are bypassed this way and work fine

You can bypass it by just taking the arm off so the switch is always open. But you didn't here that from me!

 

[Cryptic1911]

yeah totally, its just cleaner with the resistor trick since you don't have to have wires and the sensors on the wall anywhere. Just bend the leads on the resistor so its a U shape, and stick one lead into each spring clip and blammo, it fakes it out

 

[mrobins297aaa]

I have my 3800 on a 18x8 door in my pole barn, the door is well balanced.
when the door closes the last 6" of travel are very slow, I think that is normal.
Also I couldn't put that tensioner where they told you to put it in the instructions, i had to raise it up real close to the pulley in order to clear the door. I have a high lift door so it travels straight up 4' before it rolls back.

I also have a 10'w x 12'h door that I haven't put a opener on yet but when I unlatch the door it wants to go up just like yours. I'm not a door guy but I think because the door is so tall they have to have a lot of tension on the springs or by the time the door is fully opened the cables would be slack

 

[Jeff F]

I understand the resistance to some of the "safety" features, but I think the cable tension monitor is an important one.

Usually the opener works on the "door" side of the system, so the torsion spring can't ever get slack in it. On this one it is unwinding the torsion spring. Imagine that you are lowering the door and for some reason it jams up and the force monitor doesn't catch it, or the user unwittingly holds the wall button to force it down. The opener would just keep going, unwinding the spring and making a huge mess of the cable. Then if it were to become un-jammed, the door would fall with nothing to stop it. Scary.

Another question:
Can anything be done to extend the range of the antenna? It's not too bad now, but the building is metal and it could be better. Can I just attach a wire to the end of the anteanna and run it up into the attic where there is a window?

 

[PurdueSD]

IMO the cable slack sensor is one of the most important features.

The sensor saved my big door from 1 crash already. Broom handle slid between the track and the wall on one side. Why would you remove it?

 

[jdub63]

I recently installed the 3800 on my door and I assumed that the opener slowed at the top and bottom of travel. It seemed pretty controlled getting started (going down) then slowed again just prior to the door making contact with the floor. Isn't this normal operation?

My door was a little on the light side (I normally controlled the opening speed with the rope so it wouldn't "fly" up)

 

[PurdueSD]

I recently installed the 3800 on my door and I assumed that the opener slowed at the top and bottom of travel. It seemed pretty controlled getting started (going down) then slowed again just prior to the door making contact with the floor. Isn't this normal operation?

My door was a little on the light side (I normally controlled the opening speed with the rope so it wouldn't "fly" up)

That is how mine are. Believe they are designed that way...

 

[StarWolve]

I've thought about bypassing my tension sensor, because the darned thing keeps the door from going down smoothly. Every time I put it down, it gets about 1' down, and then it stops and goes back up. My installer has been out to the house twice to fix it, and each time he gets it working, but within a week it's acting up again.

I know it's the tensioner, because if I pull down on the door on the side with the sensor, it closes just fine.

Has anyone else had that problem? Other than that, I love the opener. And the speed does slow down at the ends of travel, it's designed to do that.

 

[jdub63]

I've thought about bypassing my tension sensor, because the darned thing keeps the door from going down smoothly. Every time I put it down, it gets about 1' down, and then it stops and goes back up. My installer has been out to the house twice to fix it, and each time he gets it working, but within a week it's acting up again.

I know it's the tensioner, because if I pull down on the door on the side with the sensor, it closes just fine.

Has anyone else had that problem? Other than that, I love the opener. And the speed does slow down at the ends of travel, it's designed to do that.

Is the sensor on the same side as the opener/motor?

 

[StarWolve]

Is the sensor on the same side as the opener/motor?

Yes, it's on the same side. He's moved it around on that side a few times, trying to find just the right place. Again, if I pull down on that side of the door as it's closing, it closes just fine.

 

[ovilla]

IMO the cable slack sensor is one of the most important features.

The sensor saved my big door from 1 crash already. Broom handle slid between the track and the wall on one side. Why would you remove it?

+1

My old POS i-Drive didn't have the cable tension monitor and just kept on unspooling a door that got stuck on the way down (due to a broom that got in the way - which the door sensor never even saw either). Anyway, why bypass something that takes a few minutes to install properly?

Thanks everyone for the tip on getting one light to turn on from either opener. By the way I got both of my key pads set up now to close either/both doors by just hitting ENTER.

Anybody figure out how to remotely turn on their regular lights with the opener light? My 3rd bay has my BendPak, so I'd like to be able to open the door and have a spot light come on instead, to light up the area under my other car. I think I'll just try hooking up an outlet into the light socket for now but don't like that for a long term solution.

 

[darkk]

The cable sensor is not truely a safety feature. It mearly stops motor movement if the cable becomes too loose so it eliminates any cable damage. The door should stop anyways because it has a tension sense built into the motor. If it binds, it stops, just like if something is under it when it is closing. If you door slams down then you have an incorrectly adjusted spring setup. The correct spring tension will hold the door at whatever position it is stopped at. If you want to test this theory, just pull the motor release rope and try the door. It should stay where ever you let go of it.

 

[Jeff F]

Another question...

It seems that the opener must "know" the position of the door based on the motor position and counting revolutions of the shaft. Does that mean that if the emergency release is used, it has to be reattached at the same door position? Otherwise the door position and force settings have to be done again?

For example if I release the door while it's closed, open it, then re-attach, the door "thinks" it's still closed.

 

[pattenp]

Another question...

It seems that the opener must "know" the position of the door based on the motor position and counting revolutions of the shaft. Does that mean that if the emergency release is used, it has to be reattached at the same door position? Otherwise the door position and force settings have to be done again?

For example if I release the door while it's closed, open it, then re-attach, the door "thinks" it's still closed.

No. The position is based on the location of the drive gears in the opener. When you pull the release it only disconnects the motor from the drive gears. The drive gears are still connected to the shaft so when you change the location of the door the drive gears are also moved to the new location so the opener still knows where the door is. Clear as mud?

 

[Jeff F]

Ah, that makes perfect sense.

 

[Grape Ape]

I've thought about bypassing my tension sensor, because the darned thing keeps the door from going down smoothly. Every time I put it down, it gets about 1' down, and then it stops and goes back up. My installer has been out to the house twice to fix it, and each time he gets it working, but within a week it's acting up again.

I know it's the tensioner, because if I pull down on the door on the side with the sensor, it closes just fine.

Has anyone else had that problem? Other than that, I love the opener. And the speed does slow down at the ends of travel, it's designed to do that.

I have this exact problem. It is frustrating!

 

[C G]

I bought my 3800 from nova65ss. I also have a pole style building. I think my door is 8x14. The guys that put in the door balanced it perfectly. Before I installed the 3800 I could open the door and it would stay wherever I wanted it.

When installed in the opener I had to add a piece of wood to the garage door header to mount the cable sensor correctly. Overall I think the install on these things is super simple. Manual is easy to understand and it took very minor tweaking to get it all dialed in.

I think its been up for two years now and I haven't had to do anything to it. I installed it myself so I would have a good working knowledge so I wouldn't have to rely on someone else to come adjust it. I think most of those guys are used to the more common style of opener anyway. Over the years I think Ive installed four of those, and they were a giant pain in the **** to do.

Cant help you with the lighting question. I just have the one it came with since I only have one door.

 

[darkk]

I have this exact problem. It is frustrating!

I've thought about bypassing my tension sensor, because the darned thing keeps the door from going down smoothly. Every time I put it down, it gets about 1' down, and then it stops and goes back up. My installer has been out to the house twice to fix it, and each time he gets it working, but within a week it's acting up again.

I know it's the tensioner, because if I pull down on the door on the side with the sensor, it closes just fine.

Has anyone else had that problem? Other than that, I love the opener. And the speed does slow down at the ends of travel, it's designed to do that.

This is exactly why ours are bypassed using the 1K resistors. While our motor assemblies were off for the drywall guys to do that wall, I took the tension sensors and metered them out. I gave the door guy the resistors and he put them in instead of the sensors. Works great now and no more erratic door action.

 

[BHR4CE1]

It seemed pretty controlled getting started (going down) then slowed again just prior to the door making contact with the floor. Isn't this normal operation?

Mine does that exact same thing.

 

[Jeff F]

For those having problems with the tension sensor:

I'm curious where the sensor is mounted, I would think that the farther away from the pulley it is, the more sensitive it would be.

How are your doors balanced? If pulling down on the door as it goes down solves the problem, maybe taking some tension off the spring would allow the door to keep a little more weight on the cable and prevent the problem?

Where do you have the top limit set? Maybe setting it so that it stops just as it clears the header would help? Mine seems to get "bouncy" if I let it go all the way up.

 

[PurdueSD]

Not the best picture but maybe this will help some of you guys. Did you shim the sensor out so it mounts flush with the door jam?

 

[Jeff F]

Has anyone done anything to extend the range of the transmitter like extending the antenna? Mine are installed in a metal pole building with dual-layer steel (insulated) doors, and the range is inconsistent. Sometimes I can open/close from my house (200'+ away) and sometimes I have to get right up to the building.

The building does have a large window in the front attic, and I'm thinking that if I could extend the antenna into the attic near that window it would help. Ideas?

 

[jimmyz80]

I've been having similar problems with my new 3800, and stumbled upon this thread. My installer is a 3800 fanatic, and installs a ton of them. He bypassed the tension sensor on mine because he claims they have nothing but problems with the sensor on high lift door setups. My ceiling is about 14' tall, so the door goes all the way up the wall, and then only cuts in along the ceiling for 2-3' or so. It all works great, except when the door is closing, it gets a bit jumpy for the last foot or so before it hits the ground. Sometimes it's so jumpy that the opener reverses itself and opens the door.

If I pull the disconnect and operate the door manually, it stays wherever I position it, and it moves smooth as silk through the entire range of motion. I'm just not sure what's causing it to be jumpy during that last one foot of closing. Anyone have any suggestions on what to check? It's a pain to have to watch the door close alllll the way, to make sure it doesn't reverse and end up wide open.

 

[Jeff F]

A few thoughts, FWIW.

What are the dimensions in your installation of:
-The mounting surface of the sensor to the mounting surface of the torsion spring
-The mounting surface of the torsion spring to the cable
-The centerline of the torsion spring to the centerline of the sensor roller

Seems to me that the best performance will come from making sure that the sensor is not mounted too "proud" of the cable (which would reduce the distance from the "normal" posiiton to the switch position), and not too far away from the pulley, since any oscillation in the cable will cause more travel the further away it is from the pulley.

If the sensor is positioned too far proud of the cable, maybe try doing something to make the OD of the pulley a little larger?

Also, my door is wound pretty tight (it goes up on it's own) and mine doesn't get jumpy at the end. Maybe have the installer wind the spring a bit tighter?

I did "flip" my sensors:

 

[Teken]

Bullet Points:

- A properly adjusted torsion spring on a OHD should be adjusted so that the door will stay in ANY position in its travel. It should never require so much force to push up, or have the reverse effect of simply rising on its own.

Doing so will affect the GDO motor, sensors . . .

- 90% of the jack shaft installs I have done required that the last door panel be slightly over hanging and not have the door completely horizontal. This affects the top limit sensor reached status of the GDO.

- 75% of the installs did not place the cable tensioner sensor in the required position. As it did not operate correctly installed this way. While the last 25% worked with no problems, can't explain the last 25% as it seemed like a fluke and the install and distance placed was exactly the same with shims and all.

- Extending the antenna is best accomplished by replacing the original purple wire with your own and running it straight up into the ceiling.

- Yearly inspection and testing of all safety devices is mandatory. Such as the stop limits for up and down. Reversing pressure threshold, and the blocked object sensor.

Not inspecting and validating these 3 key area's can cost you dearly in products or life.

A little girl in our area was crushed and almost died because two of the three safety settings were not checked annually for faults / improper limits.

 

[stilinsm]

Guys,
Make sure you plug your 3800s into a surge protector. Just installed 2 units 2 months ago. One stopped working all together. Liftmaster CS indicated that the main board is fried. Asked if I had them plugged into surge protectors... I did not. Asked if we had storms / power outages lately... we did. Apparently damages that maybe attributed to surges are not covered under warranty, eventhough no where does it state that it is not, nor does the instructions recommend the use of surge protectors, nor is it listed as an available option on the instruction sheet, but out of the kindness of their hearts (sarcasm), they're sending me a replacement board.
Just bought two 990lm liftmaster surge protectors off ebay.

 

[marc@kentucky]

Guys,
Make sure you plug your 3800s into a surge protector. Just installed 2 units 2 months ago. One stopped working all together. Liftmaster CS indicated that the main board is fried. Asked if I had them plugged into surge protectors... I did not. Asked if we had storms / power outages lately... we did. Apparently damages that maybe attributed to surges are not covered under warranty, eventhough no where does it state that it is not, nor does the instructions recommend the use of surge protectors, nor is it listed as an available option on the instruction sheet, but out of the kindness of their hearts (sarcasm), they're sending me a replacement board.
Just bought two 990lm liftmaster surge protectors off ebay.

Thanks for the heads up- I am installing 3 of these units next week and I just went ahead and ordered protectors for all 3.