Dripping/popping sound question

I just got a brand new furnace with new ductwork. I noticed a Dripping sound behind one of my walls and the supply vent. I checked for anything in the attic, looked for any signs of leaks, and couldn't find anything. There are no water lines anywhere near or above this system, so I'm not sure what it could be. It happens for 10 minutes or so randomly and then stops. It has been very cold here so not sure if it's normal. The noise doesn't bother me, but just wanted to see if anyone knew what it was and if I should have it looked at. Thanks.