Underbelly Heating

[RVFun4Us]

Opened the partition in the storage area of my 3270RS Bighorn today for the first time. Wanted to scope things out down there. I located the converter in there, obviously the furnace and all the electric and water lines. I then vacuumed up metal and wood shavings. I then noticed the two duct hoses coming out of the furnace on the storage side. One I believe went up into the bathroom area, the other probably hooked into the lower family area. What I would like to know is exactly where these duct hoses come out into the floor area? Do only two hoses heat the whole rig? Or did I miss one? Second question: Is there also a duct hose that heats the underbelly? On my 3055, it was very obvious. But I can't see one in the 3270?

 

[danemayer]

If your furnace is mounted horizontally, there could be 2 ducts attached to the rear of the heat chamber. Our 2011 Rushmore has 6 ducts - 5 are 4" and 1 is 2" that heats to the underbelly. 2 ducts were attached to the rear of the heat chamber. One to the front, and 3 on the left side.

One duct to the bedroom, one to the bathroom, one to the stairs, one to the middle of the living room, and one at the rear of the living room.

How many floor registers do you have?

 

[RVFun4Us]

Dan,

We have three in the main living and kitchen areas (one at the end, one by the island and one by the refrigerator), one in the bathroom, and one in the bedroom. The only two ducts I could see coming out of the furnace were both on the same side. The furnace does lay horizontally. Just could not see any other ducting unless the underbelly blows straight out of the furnace. Wonder if there are any diagrams of the heating duct routing from the furnace on a Bighorn? Need to know how they are routed, especially in the underbelly for the winter months. If I truly only have two heating ducts coming out of the furnace, that has to mean that the heat registers are sharing the same ducting system. Am I missing something here?

 

[danemayer]

I doubt there's any doubling up of duct connections to the furnace. There has to be enough ducting attached to allow air from the blower to move through the combustion chamber, or the furnace will overheat and shut off. I'd bet that if there were only 2 ducts attached, your furnace wouldn't work.

With drop-frame units, the furnace ducting to the middle and rear of the living area, and the 2" stub to the underbelly, all go down and back. If you take out a few of the mounting screws in the front section of the coroplast, you'll probably be able to see some of that ducting. To see the rest, you'd have to cut into the rear section of the coroplast.

Is this simply curiosity, or are you planning on winter usage?

 

[RVFun4Us]

Plan on camping during some of the winter months, mainly over the holidays. I only took out the partition next to the UDC. If I took out the middle partition also, I may be able to see more around the furnace, especially into the drop-down area. So you say there is a 2" stub where heat is flowing into the underbelly? If so, that is probably why I could not see it. The ducting is probably there but just not visible from where I was looking.

 

[danemayer]

In our case, the 2" duct stopped right at the drop-frame transition, so it wasn't really providing much heat to the rear 2/3s of the trailer underbelly. I extended our with a loop through the rear section per someone else's modification. The loop has slits in the duct about every foot.

That said, if you're thinking about sub-zero (F) weather, you'll need to do more. Check out our Water Systems Winter Usage Guide for tips.

 

[RVFun4Us]

Obviously the water lines are my main focus here. As long as there is some heat flowing around them when the furnace is running, then they should be OK. Not sub-zero temps, but mainly in 20s and low 30s. Also could run a flood light behind the UDC if necessary but that should be a last resort. Sure everything is OK, just learning the basics of the new rig. Thanks Dan.

 

[travelin2]

Obviously the water lines are my main focus here. As long as there is some heat flowing around them when the furnace is running, then they should be OK. Not sub-zero temps, but mainly in 20s and low 30s. Also could run a flood light behind the UDC if necessary but that should be a last resort. Sure everything is OK, just learning the basics of the new rig. Thanks Dan.

You and your BH will be just fine in below freezing temperatures as long as you are running the furnace for heat. You can supplement with electric heater(s) but not so much the furnace doesn't run.
We've spent a number of nights in ours with both day and nighttime temperatures below freezing as well as with strong cold winds blowing against the walls.
At those times fill your FW tank because your basic water hose will freeze. We've been in parks in March and April where we were told the water would be turned off due to freezing temps. Another reason we carry water on board.
I think we probably have the same furnace as you and there are 5-6 runs coming off mine. I know this because a mobile tech had mine out last May when we had a failure (another story).
Place a remote thermometer sensing unit in the basement behind the wall away from your converter to monitor the under belly temperature.