Spent 4 hours on a door contact because of a hidden metal shim

Had a job in a 1950s house where the client wanted a sensor on a solid wood front door. The magnet wouldn't align with the contact, no matter how I adjusted the bracket. Kept getting a tamper fault. Turns out, a previous owner had put a thin strip of sheet metal inside the door edge to fix a hinge problem, and it was messing with the magnetic field. Finally figured it out by holding a spare magnet along the edge until it stuck. Had to move the whole assembly 2 inches up. Anyone else run into old hidden repairs throwing off your installs?

2 comments

2 Comments

anthony_fox901d ago

Yeah, a compass is smart. I just use a spare magnet from my kit to sweep the area first. It shows you the dead spots before you commit to a spot.

nancys901d ago

That "hidden metal shim" problem is a classic. I've found a small compass from a hardware store is great for spotting magnetic interference before you drill. It saves a lot of backtracking on those old houses.