Why does nobody talk about how door interlocks fail in the cold

Found out from a Otis manual last winter that below 20 degrees the lubricant in the lock mechanism can thicken and cause false open signals, has anyone else had ghost door faults on a cold morning?

2 comments

2 Comments

scott.grace20d ago

That bit about the lubricant thickening tracks with what I read in a Schindler service bulletin a few years back. They said the contact pressure drops when the grease gets stiff, which can make the door relay think the lock hasn't fully engaged. Had a building manager in Minnesota tell me they had to switch to a synthetic grease with a lower pour point to stop the false open signals on their elevators.

beth_stone20d ago

Oh man, that's rough. Those false open signals are such a pain, especially in a place like Minnesota where the cold gets really serious. I remember hearing from a guy who managed a building in Chicago and they had the exact same problem every single winter. The grease would get so stiff the door lock sensors just couldn't tell what was happening. It's wild how something as simple as the right grease can make or break the whole system. Good on that building manager for figuring out the fix, it's not always obvious what's going on when the sensors start acting up. You really have to get into the nitty gritty of how the mechanics actually work down there.