Humidifier
Winter humidifiers leak quietly into mechanical closets.
A cracked tray, a stuck valve, or a clogged drain can wet the closet, the carpet, and sometimes the suite below. It can look like a heating-pipe leak if nobody opens the cabinet.
Look at the humidifier before you blame the boiler.
A wet jacket around the furnace cabinet is a different story from a pinhole on a domestic line.
Shut the humidifier saddle valve if it is labelled and dry.
Leave a note. Heat can stay on without the humidifier in many suites.
Condensate is not domestic water, but it still damages.
The finding should say which system wet the floor so the repair matches.
Questions people ask
Can a humidifier stain a ceiling two rooms away?
It can if the closet sits over another suite. Distance does not prove a different source.
Should I keep running it to ‘put moisture in the air’?
Not while it is leaking. Dry air is cheaper than a wet floor.