Can I stop that cold draft from the furnace area?

[danandbetty]

I know we've talked a lot about how drafty all RVs are but I have a specific question about my 2011 3400RL. On this model the furnace return air is through two decorative wood grills in the steps that go up to the bedroom. The problem is that when the furnace is not running there's a terrible blast of outside air coming from under the stairs that reaches across the floor into the living room. It would blows out candles (if there were any) on the end table in the living room. This is a BAD draft depending on how much wind is blowing outside.

I removed the bulkhead panels in the basement and inspected the area behind the furnace and steps to find that there's nothing to stop outside air from blowing in through the sheet metal box that houses the furnace from traveling into the belly area (tanks and water lines) as well as into the living area of the trailer. I can see daylight past the furnace. I know that gas furnaces must be vented well but it doesn't make sense to me to expose the water lines (and the inside of the trailer) to this much cold outside draft in between furnace cyclings.

My old '02 3655FL Montana did not have this problem so what gives with this new Montana? (everything else is wonderful, by the way, and we love this trailer)

Is there a fix for the draft problem? Have any of you all out there encountered this problem and found a way to manage it? Thoughts or advice?

PS: While inspecting this area I also found my main 3" flex heater duct was disconnected from the main sheet metal duct work that runs the length of the trailer. It was only taped on during assembly so I reaffixed it and added screws to hold it. If your floor vents are not blowing a good volume of air check to see if the furnace flex duct has disengaged from the sheet metal ducting...apparently that fitting is only taped in on this model and needs to be secured better. For clarification...this is not part of the draft problem. That's a separate issue.

Thanks for any help you can give on the draft problem.

[hookman]

If it is under warranty I would take it to the dealer and show him what you found. Our 2008 is the has the same cold air return in the stairs and we have no draft when the furnace is off.

[camper4]

I had to build a wall of sorts. I didn't have a breeze but I could see day light past the furnace. I did not do a perfect job. It would have taken a lot of work to seal the bottom up and since I don't camp below freezing very much, I stopped there.

[bigred715]

We have a draft when the furnace is not running. Sometimes we use just the fireplace for heatand I cut 2 pcs of cardboard to block off the stairs. Tis works for us. Its been in the high 30's at night here in Mesa, Az.

[exav8tr]

I have placed an air filter behind these grills to halp filter the return air to the furnace. We have no drafts coming from this area in our '06. Perhaps these filters would work for you. I did have to cut to size......

[Clemson1881]

How high of a volume of air would some of you say comes out the floor vents? We were using ours in Pigeon Forge last week and I was disappointed at the volume of air coming from the vents. The furnace kept the trailer warm in 29 degree temps, but I didn't think enough air was blowing in.

[jackel1959]

danandbetty,
Try this link: http://www.montanaowners.com/forums/...ad.php?t=39628
This is what I did to remedy the problem in both hot and cold weather in our 3455SA. The layout of our rig is "similar" to yours from the entry door rearward.

Jack

[berridge]

I have blocked off one of the risers completely and built a sliding door to block the second riser. When the furnace is running we open the slide door. When the furnace is off we close the door so both risers are completely blocked. Without this we have a blast of cold air coming in! The Montana system is like locating your home furnace in the garage and then cutting a hole in the wall to let the return air back. We also had the air supply duct from the furnace to the plenum fall off. It was held on by tape only. I added 3 metal screws to secure it.

[c214dick]

"PS: While inspecting this area I also found my main 3" flex heater duct was disconnected from the main sheet metal duct work that runs the length of the trailer. It was only taped on during assembly so I reaffixed it and added screws to hold it. If your floor vents are not blowing a good volume of air check to see if the furnace flex duct has disengaged from the sheet metal ducting...apparently that fitting is only taped in on this model and needs to be secured better. For clarification...this is not part of the draft problem. That's a separate issue."

We found the same problem on our 08 3400 RL while we were tracing wiring related to our slide problem. With it now attached, we have noticed a considerable improvement in the heating of our coach.

[danandbetty]

Well, OK. I'm getting the idea that my Montana isn't alone with it's draft problem. You've given me some good ideas. I was thinking about framing the face of the vents on the stairs with velcro and cutting a decorative piece of thin plywood or possibly Naugahyde to fit so they're removable when the furnace is in use. The other possibility is to make a bulkhead to block off the air flow behind the furnace (to keep the cold air off from water lines and tanks as well as from inside the trailer).

I looks like Jack's handi work is by far the most practical and innovative. I'll be looking for some decorative closable vent covers like yours....thanks for the creativity.

I would simply not use the trailer in cold temps but I leave Alaska in the fall to avoid cold temps and you know how the winter cold has been unusual all over the lower 48 this year (I hate this global warming). We left Texas and returned to Tucson because of it but it's been pretty chilly here off and on also. It seems that even a full timer can't avoid some freezing weather. Also, we return to Alaska in late April/early May and sometimes travel through some freezing temps on that trip so I WILL be modifying my Monty to get rid of that draft!

Currently at Davis-Monthan AFB fam camp (Agave Gulch)in Tucson.

[summers]

I really like the mod that jackel 1959 did, one other thing that could be added to this would be light wieght back draft dampers. They would open when the furnace is drawing return air and shut when the furnace is off, this would keep you from having to open and shut the registers. This wont help with the under belly but would keep air from entering the living space. You will have to build a box to enclose the registers and have the damper enclose the opposite end.

[Hooker]

These things leak like sieves. I put a piece of cardboard behind the vent in the stairs, stuffed pads in the overhead fans, stuff towels, rags, etc where the corners of the slides met the floor...still extremely drafty. I can't imagine any vent needing to be open for the furnace intake, there was plenty of air on the floor for furnace use.

[richfaa]

We do have the drafty when windy package and we did today check the vent under the stairs. There is s draft coming in at the far right corner. Good summer project.

[MuddyPaws]

It must be part of enjoying the great outdoors.