Hoping someone can be a hero on this one... not much online ~ not sure who/how to fix it; whenever the heating in my condo turns on, minutes later there is a rhythmic tapping (constant) in the ceiling on the opposite site of the condo along where the heating ends. I'm not sure what it could be (contracting due to hot/cold) but I need to figure out what it could be so I can find someone to fix it (probably involve opening up the ceiling?). Any input? Seems like a common problem but how is it obsolved? Thx

First of all exactly what kind of heating system do you have?

Sounds like thermal expansion of the duct system binding against the structure. May not be a quick fix-hero scenario.