PLEASE HELP SAVE MY MARRIAGE BY ELIMINATING THIS HVAC NOISE!
I live in Louisville, Kentucky and recently bought a large house built in the early '90s. It has a RUUD Delux 90 Plus forced air natural gas heater. The master bedroom is on the first floor and there are finished rooms in the walkout lower level below the master.
I've had the heat for only a couple weeks and have noticed at night (ambient temp in low 40's) that every time the heater kicks on, about 1 minute into the heat cycle a loud "pinging" noise comes from the vent on about 30 second intervals. It will continue the whole time the unit is on and then for maybe another 3 or 4 minutes once it shuts off. The HVAC unit itself is pretty far from where the noise is and I am pretty sure it is thermal expansion in the ducts. The ducts are your typical rectangular metal (sheet metal or whatever). They are the uninsulated but above the drywalled ceiling in our finished, heated lower level.
The noise actually comes from two different vents - one that services the master bedroom and one directly under the master bedroom that services the room below. The thing sounds like chitty chitty bang bang driving through my bedroom at night and is driving my wife crazy.
So the obvious questions....
What exactly is causing this and is there anything I can do to fix it without ripping into the drywall? The rooms are nicely finished with crown molding, etc. - I really don't want to have to tear into all that. The main duct in that area is boxed in on the ceiling and the individual vents in question run between the floor joists.
Please tell me someone has a solution???