To clarify; I have not yet sprayed anything into the dial mechanism.
This used to be a light switch, but my son kept leaving it on. So I swapped it out for one of these dials about 2 years ago. Now it seems to be getting stuck around the 10-min mark and being left on all day.
I’d prefer not to replace this dial again; the house is old and the wiring in that receptacle was already pretty hard to work with. But I mean I’m not going to burn my house down in an effort to save myself 10 minutes and $10.
Is it safe to use a silicone based spray on it?
Contact cleaner was my first thought too, I’ve used it successfully to unstick potentiometers like volume knobs.
In this case, depending on the source of the failure, neither that nor the silicone spray might be sufficient. There’s probably a spring in there which could be stuck or partially rusted from moisture (in which case a selective dose of WD-40 would help, followed by some form of lubrication). I’d try to take the cover off and take look at the mechanism first.