I have two 12'w x 14' tall doors and one 16'w x 14' tall door in my metal building.
I installed Liftmaster 8500s on both 12' doors with no issues.
The 16' door is too heavy for the 8500 opener.
A MJ50 or MH50 opener is necessary for the heavier door.
The 8500 has a cable tension monitor that prevents the cable from being unspooled if the door doesn't close due to an issue and/or an obstruction.
The 50s do not have any such tension monitor.
What prevents them from unspooling the cables in the event of an issue?
I installed Liftmaster 8500s on both 12' doors with no issues.
The 16' door is too heavy for the 8500 opener.
A MJ50 or MH50 opener is necessary for the heavier door.
The 8500 has a cable tension monitor that prevents the cable from being unspooled if the door doesn't close due to an issue and/or an obstruction.
The 50s do not have any such tension monitor.
What prevents them from unspooling the cables in the event of an issue?