More then likely its your ductwork. Its either light guage and flimsy or when it was fabricated they ever crossbroke the metal. A crossbreak is a slight bend at 45 degree angles formed into the metal panels of the duct to make it more rigid. If you had the furnace replaced its a pretty good bet they made up new supply and return plenums and thats the source of the noise. When the blower comes on the duck expands outward and could sometime sound like thunder. Seen/heard it before many times. What you need is a tech whose got some exposure to furnace install as well as duct install. He has to attach 1 inch angle strips to the ducts with sheet metal screws to make it more rigid. It's no big deal unless the ductwork has been covered over or boxed in.

By noise, I mean the noise of combustion. The air handler fan does not make excess noise.

Can't see video due to broken link. This post was edited by ionized on Wed, Sep 24, 14 at 20:16

I can't blame a layman or old timer for confusing the terms when in fact years ago there were hot water furnaces. And in fact still are outdoor open system wood boilers/furnaces. You see the term furnace also depicted an open hot water heating vessel. The proper term boiler became prevalent when describing a closed system vessel. So going back to the 50's and before, when risers and open tanks were used in attics, sometimes with feeders, in fact they were "hot water furnaces" judiec, Any fix yet? Being related to an appliance with a solenoid that uses water, I'm betting on a singing PRV on the boiler or it's the tank water heater, or piping.