Routing your own furnace vents...

[TurnThePage]

My trailer has in floor ducting. The most important of the three vents has never worked that well, and has gotten worse. Now the floor actually gets warm where the duct is likely leaking. I thought I could just block that vent and reroute to a new vent installed in the side of the cabinet where the furnace is housed. It turns out the the three vent hoses/ducting from the furnace feed into a manifold that disappears under the floor before it separates out to the various ducts. That particular section of floor is not accessible from under the trailer.

I'm now considering sealing all three floor vents and the manifold, then routing the three furnace ducts through the cabinets that span most of that side of the trailer. I will have to penetrate a couple walls, etc.

I guess I'm just looking for advice or a bit of wisdom.

[Bammer4]

SoundGuy wrote:

TurnThePage wrote:
I guess I'm just looking for advice or a bit of wisdom.

One winter a mouse (and perhaps his family) got into the camper and apparently wintered in 2 of the 5 lengths of ducting. I discovered this when I first started up the furnace in the spring :E but thought I could simply clean them out. Not a chance, I ended up having to replace the affected ducting with brand new - that turned out to be not a difficult task at all because it was all above floor. Had this been underfloor ducting this job would have been a nightmare as I'd have had to first remove the Coroplast to get to the ducts. :M

[ktmrfs]

DutchmenSport wrote:
My last camper was an Outback 298RE travel trailer. It had a "Polar Package", whatever that means.

I always winterized as normal, but we'd continue using the camper without water in the tanks or lines in some pretty cold weather.

What I found out pretty quick, was the air ducts are designed somehow, to keep the underbelly warm because the water lines ran right next to them. And it seemed to use a LOT of propane. Floors always felt warm when the inside of the camper seemed to struggle, and the furnace would run constantly.

Well, considering the water lines had nothing but RV antifreeze in them, I got a little creative. The furnace was located under the refrigerator and I removed the intake cover and saw it had 3 wire-plastic ducts coming off. I ended up removing one of them, the one that led to the bedroom, as we maintained an electric heater in there. And then I did not replace the intake cover.

What happened was, the open duct port could now blow directly into the camper living space, and this simple change, changed everything. The floor was not as warm any more, and the inside of the camper warmed up much faster and much more. The furnace ran less, and we used less propane. It was a win-win. And yes, this was a 35 foot TT.

Anyway, it's just something to consider, change the air duct so the furnace blows air right at the furnace and really, doesn't go through duct work under the floor at all.

It sounds like you don't need the underbelly duct work for keeping the pipes from freezing, so this may be an alternative.

Anyway, this worked for us for 5 winters.

our 295RE was similar. I found a couple of things that really helped as well.
1) the ducting was flimsy foil lined stuff like is often seen for dryer ducting. This has two issue, one is very high airflow resistance, second is lots of heat loss. Not a very good heat insulator.

To solve this problem I dropped the underbelly and replaced all the ductwork with the 4" full metal ductwork I wrapped with the adhesive foil insulation. That got airflow up, and much more heat into the trailer vs. underbelly.
To keep the underbelly warm in cold camping I pulled the floor duct in the bedroom and kitchen and drilled a 1/2" hole in the side of the pan to allow airflow into the underbelly.

End result, underbelly stays well above freezing, trailer warmed up quicker and used less propane.

One big error on keystones part was the placement of the thermostat close to the heat vent near the bedroom. so, heat goes straight up to the thermostat, it thinks the trailer is warm, (it isn't). My solution was to install a hunter thermostat that also lets you use an external sensor and placed on on the credenza. the thermostat then averages the two readings, much more comfortable.

[Beentherefixedt]

Hi, If you open up the inside and outside access to the furnace and look carefully you will see that more than likely your furnace has some round plates about 5 inches in Dia. on both sides and probably on the front (the side facing into the camper)These are for the round flexible ducting.

You could install these and make openings in strategically placed cabinets. However this means taking the furnace out which sounds daunting but is pretty simple actually.

I just removed my furnace, cleaned it and removed a mouse mansion in the main duct and rebuilt the furnace mounting (which was one of the few things on this trailer I have found done truly badly but could have been done by an RV dealer on repair rather than the factory)

I have floor ducts also and before I would do any of the above I would get a plumbers snake and attach a wet rag to the end and run it through the ducting. You may have a mouse who has constructed a mouse mansion in your ductwork.

As for shutting down certain ducts this is not a problem for the furnace unless you shut down more square inches in exhaust opening than there is at the furnace outlet. Part of the problem with so many ducts in a small area is that you are experiencing a "pressure drop" in the air flow resulting in less force coming out of the ducts.

I also agree that a camera look in the ducts might be a good idea to see if there are holes.

Now my water pipes all run inside the cabin except for a short run from the water inlet/water heater to the Kitchen Sink area. I added extra insulation for them myself where they can be reached. I can use water well below freezing as long as the hose doesn't freeze up.

Good Luck

[time2roll]

I added two ducts to supplement the floor ducting. I added one to each side of the furnace from the existing knockouts. Connected to a vent on each side of the furnace through the cabinet. Tons of heat from the added vents and still a little from the floor.

[Lwiddis]

“Rent a camera...” Great idea. I never would have thought of that.

[SoundGuy]

TurnThePage wrote:
I guess I'm just looking for advice or a bit of wisdom.

I'd say you're on the right track installing your own above floor ducting. Although our previous K-Z Spree had an enclosed underbelly the furnace ducting was just as you describe, above floor and through various cabinets. One winter a mouse (and perhaps his family) got into the camper and apparently wintered in 2 of the 5 lengths of ducting. I discovered this when I first started up the furnace in the spring :E but thought I could simply clean them out. Not a chance, I ended up having to replace the affected ducting with brand new - that turned out to be not a difficult task at all because it was all above floor. Had this been underfloor ducting this job would have been a nightmare as I'd have had to first remove the Coroplast to get to the ducts. :M

[DutchmenSport]

My last camper was an Outback 298RE travel trailer. It had a "Polar Package", whatever that means.

I always winterized as normal, but we'd continue using the camper without water in the tanks or lines in some pretty cold weather.

What I found out pretty quick, was the air ducts are designed somehow, to keep the underbelly warm because the water lines ran right next to them. And it seemed to use a LOT of propane. Floors always felt warm when the inside of the camper seemed to struggle, and the furnace would run constantly.

Well, considering the water lines had nothing but RV antifreeze in them, I got a little creative. The furnace was located under the refrigerator and I removed the intake cover and saw it had 3 wire-plastic ducts coming off. I ended up removing one of them, the one that led to the bedroom, as we maintained an electric heater in there. And then I did not replace the intake cover.

What happened was, the open duct port could now blow directly into the camper living space, and this simple change, changed everything. The floor was not as warm any more, and the inside of the camper warmed up much faster and much more. The furnace ran less, and we used less propane. It was a win-win. And yes, this was a 35 foot TT.

Anyway, it's just something to consider, change the air duct so the furnace blows air right at the furnace and really, doesn't go through duct work under the floor at all.

It sounds like you don't need the underbelly duct work for keeping the pipes from freezing, so this may be an alternative.

Anyway, this worked for us for 5 winters.

[MFL]

I like having my heat ducts factory installed through cabinets. My FW is ADVERTISED as a 4-season, so ducts travel near water lines. I have only one floor vent, near the shower stall. A small duct blows into enclosed/insulated basement. I have a duct that runs through basement area, next to waterlines, and also right beside water pump.

While most are not truly 4-season, I have to say, mine was really well thought out, with the duct placements. I have camped in the low 20s, with great results, and even heat throughout. With ducts going through cabinets, no need to leave doors open, to heat water lines.

Jerry

[midnightsadie]

rent a camera ,push it threw the duct you,ll find out whats going on. did this to a sewer drain on a house ,like watching tv.

[garyemunson]

I thought the same as you about the warm floor, careful examination just showed it gets warm because the duct is right up against the bottom of the floor. My furthest ducts don't provide the airflow I would like while the ones closest to the furnace put out too much. Still working on a fix for that. Am concerned if I partially block the closest vents, the furnace itself may overheat from the restriction. An added duct right at the furnace plenum is probably the best idea to carry heat to where it is needed and relieve some of the excess flow by the furnace. This would fix the issue without causing a restriction right at the furnace. I think adding additional vents would be more productive than closing existing ones and installing new ones.