I've Discovered a Design Flaw

[dieselguy]

I believe I’ve discovered a design flaw in the newer Montanas with the dropped frame. I’ve never been too impressed with the heating and cooling of my 2011 Montana. It’s also been the draftiest fiver I’ve owned. There’s a 1.5” thick aluminum framed wall that separates the main cargo bay from the kitchen level of the fiver. When I removed the white partition from the back of the convenience center as well as the pressed board wall from inside the cargo bay … I got a big surprise. There is a 1.5” gap between the main floor area and the partition wall. This gap allows air conditioned or heated air to fall into the belly and into the dead space between your frame and the lower aluminum skirting both of which are by no means well sealed. On a windy day this gap also allows air from the outer dead space and belly to blow up into your fiver to a certain degree depending on open windows or vents. There is also about a foot of wall missing right behind the convenience center. With the white panel behind the convenience center removed, you can look right at your hot water heater and furnace or on into the living area. Finally, there is about a 2.5” gap between the bottom of the bedroom floor and the top of the aluminum framed wall in-between the floor joists.
As seen in the photos, I added four 24” by 10.5” pieces of insulation in-between the main floor and the cargo partition wall. I then cut a 12.5” by 31.5” piece of plywood to cover the hole behind the convenience center. (notched out for water and drain lines) I also added blue foam insulation in-between the aluminum frame in the cargo area and the bedroom floor. I‘ve already noticed my draft is gone and with the cool nights lately, I’ve noticed the furnace doesn’t cycle as much. Time will tell this summer as to A/C improvement. One last note … since I had the wall removed, I cleaned up the installation of the electrical wiring, cable lines, and furnace vents as well as checked all water connections.

[BrokenElbow]

nice job.

[stiles watson]

Just one design flaw?

[dieselguy]

I suffer from "tunnel vision" I'd guess ...

[kramperD]

Nice work, DG! Thanks for the pics!

[Lee F.]

Question: Will that cause any problems with the heated areas that keep the pipes and holding tanks from freezing?

[Mudchief]

Nice work and thanks for the pictures.

[dieselguy]

Lee:
There is a 2" duct that goes thru the floor directly off your furnace that is supposed to heat the underbelly enough to keep it from freezing up. This is a standard feature.

[zman08]

DG. Nice job with good supporting pics. Looks like another summer job for me...

[jackel1959]

Looks like another project to add to the "Mods & Improvements" list for the home on wheels. Thanks for the post!!!!!!

Jack

[Lee F.]

Thanks Dieselguy,

Looks like a very worthwile mod.

[SlickWillie]

Wonder if it is that way on other units? I'm thinkin' the craftsman that built your unit may have a memory like me; went to lunch and forget where he left off at.

[Parts Ed]

All the water connections make it look like a Rube Goldberg contraption.

[scductman]

Not to be a smart butt But every day I love my old 06 more!! I already fixed most of the problems I had and now I just camp and try to keep up with the mods of you folks and you know who you are!!!! LOL.
Bobby

[Parts Ed]

I think he is pointing his index finger at you Ozz.

[CORattler]

Interesting that you should post this now. I was at my Monty this past weekend and had pulled off the back of the service center to check things out and saw the same thing. I tightened up some loose water connections, repositioned and zip tied some wiring into a more manageable bundle and re-routed my hot water heater igniter wire which was hooked around a sharp edge on the furnace. I also tightened a loose furnace duct. Thanks for the pics and ideas. I intend to do the same to make a good RV even better.

[Ozz]

I had that big white cover off mine again so I could route my coax through there. I noticed my heat duct (3") was tied in to the main run with a small boot. It was hanging down where it attach's, so 1/4 to 1/2 of the airflow leaked by and didn't even go into the duct. The boot and flex was just taped onto it, no screws...
The main run is a rectangle probably 8"x2", being fed by a 3" flex hose. Does not compute.... not big enough, so I am installing a take-off boot and a 4" run to it. P.Poor work by our Old world craftsmen...

[jackel1959]

Ozz,
For those of us who are not real familiar with HVAC, some photos of what you end up doing would be.....well as they say "worth a thousand words" Just one more thing to add to the list.

Thanks,
Jack

[jliveit]

Nice job, but how is the heat from the belly to get to the convience center and cargo area? I was told that it was that way to let the heat get to those areas when I was going to do the same thing. Only time I have noticed drafts inside was if I had a cargo door open.

[berridge]

Because of these many openings the area under the stairs in my 3075 there is a large volume of cold air comming through the stair riser vents and into the main cabin when the furnace is not running. I, as well as others, have installed some form of sliding shutter device to shut off these vents except when the furnace is running. Adding insulation to fill the gap from the underbelly is now on my "to do" list. Thanks for the post.