How does the furnace heat the underbelly??

[RGF911]

I have a 2010 300bh outback. I emailed Keystone and they said there is a 2" duct that heats it, but I dont see that size duct connected to the furance. Its brand new and the front bedroom duct wasnt even connected to the furance I had to do that my-self. I found the vent wasnt blowing heat.

[hankpage]

The plenum on your furnace should have knock-outs on five sides. They may have used a bottom outlet for the 2" duct to the under-belly. Remove the plate from one of the unused outlets and you may be able to see if this is so. I think my Cougar has one 2" branch off the end of the main duct in the center of the floor.
No air-flow should have been picked up on your dealer walk through and corrected then.
JM2¢, Hank

[RGF911]

Cool, Thanks I will have to look under the furance. Thanks again

[LarryD]

Many units and brands have the main rectangular duct running front to back in the main floor between two floor joists. In some cases, the manufacturer simply cuts a hole thru the bottom of this duct to provide air flow to the underbelly. This hole is unlikely to be centered directly under one of the floor registers, but you may be able to search for it by removing the register and using a flashlight and small mirror to look along the duct.

On my brand, I found the hole while I had the entire underbelly panel removed. I covered the hole up, I couldn't see wasting propane to heat the underbelly when temps were in the 30's to 50's. Besides, the underbelly is also heated by radiant heat from the entire main duct anyway because with the typical 3" floor joist (really 2-1/2") there is no room for insulation under the duct anyway. So, a 20 ft long duct that is maybe 11" wide will radiate a lot of heat into the basement.

Several more points. The basement is not air tight, if it was, then the furnace could not force air into it anyway. And having a direct path between the living area and the basement means that when the furnace is off, cold air will enter the living area thru that opening. So, I depend on just the radiant heat to keep the tanks from freezing. Also, the first thing that should freeze is not the tanks anyway, but the fresh water pickup tube for the pump. Since shutting off the basement vent a few yrs ago, I have camped in temps as low as 14 degrees and not had a problem with the tanks or the pickup tube.

I've got 22 yrs camping experience with 5 different brands, but do your own research and make your own decision.