LFM-20 not working with door switch


(Adwait Joshi) #1

I have 3 garage doors and I have installed 2 LFM-20’s to it. Two of the three work fine. But one of them is giving me trouble. As soon as I connect the power to the LFM-20, my door switch stops working. Its weird because this works fine in the other 2 cases. Anyone have any idea what might be going on ?


(Edward Pope) #2

If they are wired the same way, and the others work, I would assume that the one that is not working has an issue of some sort.

How do you have them wired? And have you tried moving one of the working ones to the one that is not working to rule out a hardware issue?


(Adwait Joshi) #3

I figured out what was happening. This relay switch has a on and a off mode. When the switch is on, the door switch doesnt get any power (I am assuming) so the door switch doesnt work. When the LFM-20 turns off the door switch shows power.

When I added the switch to my ST Hub, something went wrong and the switch wont go in the off position. I removed the device and re-paired. Nothing was wrong with the switch or the wiring. Thanks for your help and hope this thread serves as a solution for someone who gets stuck!


Liftmaster Wall Switch partially working with LFM-20