I have a 310QB and when I turned on my furnace I noticed it blew hard from the vent on the side of the dinette. It had a 3" or so duct running to it. The vent on the back of the other dinette seat barely blew. It had a smaller 2" - 2 1/2" duct. The bathroom had the bigger duct and blew so much you couldn't leave the door closed while the heat was on or it was like walking into a sauna. The front bedroom had little to no air flow and the smaller duct. Finally, the vent in the back room where the bunks are is mounted under the seat of the small dinette like the main dinette. It had absolutely no air flow. Took up the seat and discovered there was just a vent there. No duct running to it, just a vent mounted there with nothing. Here's my question. Is there anyone else with this problem? The back of my toilet gets so hot I'm afraid it's going to damage it, aside from it being extremely hot in there if you close the door while the heat is going. Looks like I'll be contacting Heartland to come up with a fix for this problem. If anyone else has experienced this I would like to know how you resolved it. Thanks for the help.