Dear Dave,
I don’t want heat from the RV’s furnace in my bedroom. Can I just cover the vent somehow? —Lynne, 2016 Sabre
Dear Lynne,
I assume you are referring to a Forest River Sabre. Since you did not provide a model, I will also assume it is a 5th wheel as I do not see any other models listed on any reseller sites. What I can find on interior photos looks to be mostly remote vents supplied by flexible foil or vinyl wrapped ducted hoses rather than residential style plenums. [From Merriam-Webster: plenum: an air-filled space in a structure, especially one that receives air from a blower for distribution (as in a ventilation system).]
These hoses have a coiled wire support that creates ridges and airflow resistance. It is rather slight and typically doesn’t affect airflow enough to worry about. However, closing vents could make a difference.
According to the floorplan photos, there are vents in the kitchen island, in the steps going to the bedroom, and on the bed pedestal. I have also found a few photos that have a floor vent in the bathroom.
What’s your point?
With most of the vents having the hose connection which I have always called “elephant trunks,” there is airflow restriction. Closing vents will cause increased airflow at the furnace. This could create increased temperature which would make the limit switch shut the furnace off. Or it could cause limited airflow, which would not allow the sail switch to raise enough to open the LP valve.
I would suggest shutting the vent and see if the furnace continues to run. If yes, then you are OK. If not, then you need to find a way to either divert the airflow in the bedroom hoses, or increase airflow in another area. This is why the hose versus plenum is important, as you can detach a hose from the vent and reroute it, but not a metal plenum.
In the case of your 5th wheel, the hose typically comes off the furnace, goes through the basement, and comes up into the bed pedestal.
This can easily be detached and routed into the basement which would still provide proper airflow at the furnace but not heat the bedroom. A rigid plenum would be much harder to reroute.
You might also enjoy this from Dave
My RV’s furnace ductwork is exposed to the elements. How do I insulate it?
Dear Dave,
My furnace heat is distributed through cut-out channels in the RV’s flooring. It’s all surrounded by the floor Styrofoam and is quite efficient. However, the duct over to the floor inlet is just plain painted steel, under the coach, and exposed to frigid air. What would you suggest to insulate the “naked” duct under the floor? It’s about 20″ wide, 8″ deep, and 40″ long. Insulating even the belly of it (20″ x 40″) would, I think, have benefits. —Gregory, 2003 Winnebago/Itasca Sunova
Dave Solberg is a leading expert in the RV industry and the author of the “RV Handbook.”
Read more from Dave here.
HAVE A QUESTION FOR DAVE?
Send your inquiries to him using the form below.
##RVDT2248
Aren’t all 5th wheels just warmer in the bedroom because heat rises? Not bad in the cold, but no fun in warmer weather?
Not all 5th wheels have the bedroom on the front upper deck, but I get your point.
You’re right Capt. I’ve seen some living rooms or kitchens in front that I really liked.
If you shut off one you should make another. My fifth wheel didnt have one in the bathroom and was running hot so I added 2 new ones. The temperature of the furnace went down and bathroom became warmer.
Don’t forget, everything is made as cheaply as possible. I used insulated 4″ ducting . Mine had 3 ducts coming from the furnace so I ended up with 5