Check the limits. The closed limit is
probably right on the edge of triggering.
Basically, it is probably opening
because it "thinks" there is an object below
the door. That object is probably the
floor heaving up when it gets cold.

mcq142 wrote:
I have Mac Lift Merlin Series that opens on it's own, especially during
the night. It is used on a one car door size. The larger 2 door model
instaledd in the next bay never has this problem. This has only been a
problem during below freezing temps. Thanks, Tom