Furnace noise on 2009 3605RL

[stimpy123]

I've had a furnace "bang" about 1 minute after the furnace has ignited, and then about 2-3 min after the blower stops on shutdown. The sound is similar to the sound of someone hitting the bottom of a wash tub with a wooden spoon.
I've taken our rig to Las Vegas RV and they had to install reinforcement to the ducting to stop the sound.
I'm certain that I'm not the only owner with this issue, and wondered if someone in the engineering dept. would address this in future production.
Thanks
Steve

[Rondo]

Steve-- Check past posts or search under furnace! There have been several threads on the "bang" sound from the furnace. If I'm not mistaken it is the ducts expanding and contracting. I know Ozz explained it in one thread. I'm sure there will be posts coming along to let you know what's up!