Liftmaster 8500 phantom opening

[kabinenroller]

I have two 8500’s operating the doors on my shop. One of the doors is for the “cold side” of the building which is divided from the main part of the shop by a full height insulated wall so the door is not visible from the main shop. I have a limit switch mounted on the door that activates a wall mounted light in the shop when the door is open.
Today I had a strange occurrence, I was welding in the shop using my Tig welder, when I looked over and saw the indicator light on and the door fully open. The wall mounted control panel for both doors was in the lock position which does not allow a signal from a remote to operate the door (s). The only thing I could think of is that the use of the welder caused a rouge signal that the operator picked up and caused the door to open. I have used the tig and mig welder countless times without this happening, having the door open for no reason especially in winter is not good. If it was not for the indicator light the door would have stayed open for hours instead of minutes.
Has anyone else experienced this issue?
Thanks!

 

[Skellyii]

The last 8500 I had installed had a defective circuit board that would open the door randomly, no rhyme or reason.

 

[46MGTC]

I've got a 3800 that's doing the same thing. The original wall control was a 398LM that had the display going wonky. I assumed that was the problem and replaced it with a similar wall unit from Liftmaster. Same problem so I assume the problem is with the board in the unit.
I've since replaced the wall unit with a simple Home Depot push button and after 6 months I've had no spurious openings.

I was getting annoyed waking up in the morning and seeing the door open and the heat pump running all night trying to cool the neighborhood. For a while I was turning the power to the opener off when I wasn't in the shop.

 

[HoosierMark]

To be safe just pull the disconnect red handle, Then it cannot open by the motor and door is still locked by dead bolt.

 

[kabinenroller]

Thanks for the replies. I did replace the controllers under warranty a number of years ago, this is the first time the door has phantom opened since then. I did pull the motor release rope to disable the operator from the door. Good thing is that this particular door is on the unheated side of the building and is almost never opened in the winter, I use that part of the building for vehicle storage.

 

[wssix99]

Did you see all the info on the silent recalls for the 8500 where Liftmaster changed the wall remote units to correct the phantom opening problem?

I have three of these and had the issue but it has been years of trouble-free operation since moving to the new wall remote design.

 

[wssix99]

I just posted at the same time you did. I should have mentioned that I replaced my remotes under warranty twice with Liftmaster. (The second time was the charm....)

The first time, they gave me new "old" remotes. The second time was a different design.

 

[kabinenroller]

Thanks.
What is strange is that since I replaced the control panels I have had no issues of false opening until yesterday when I was tig welding. I have used the welder countless times over the years without issue.
I might understand if I was welding using high frequency but I am not. Also only one of my doors has this issue, the door for the heated portion of the shop never opens falsely. I wonder if Liftmaster will still cover the controllers under warranty.

 

[wssix99]

This thread has some good history: https://www.garagejournal.com/forum/threads/lm8500-wall-controller-failure.365279/

Lots of tricks and conspiracies ^ but the replacements I got in October 2017 were new "old" units. In late 2018, Liftmaster made a change and allowed everyone to swap units. Around December 2018, new remotes were sent with a blue dot on the package -> these units have been good to me for 7 years. (I'm knocking on wood now...)

It looks like Chamberlain screwed the pooch again and had to recall some other wall remotes made in 2022: https://support.chamberlaingroup.com/s/889LMMC-041A7928-3MC-warranty-replacement

 

[dante2]

I did a pre-emptive strike and removed the control unit after reading about the random openings. Now it's just a push button by the door and the remote in the vehicle. Never felt the need to open or close the door with the app anyway.