rear floor furnace vent issue

[1320quick]

I purchased a 2014 Heartland Sundance XLT 285TS back in July. I have an issue with the rear heat duct. I noticed that the rear floor heat duct has maybe 1/3 of the air flow that the bathroom and bedroom floor ducts have. The front bathroom and bedroom are super hot and the rear living area is freezing when using the furnace because of this issue. I included this issue on my list of things I wanted the dealer to fix. I picked up the camper today from the dealer and they said there was some foam in the ducting so the cleaned it and tested it and it was now fine. Well I tested it when I got home and it may be a bit better but in my opinion it is still not acceptable. I can understand that maybe the air blowing out of the vent might not be as warm as the front vents because of the distance from the furnace but it seems like the volume of air should be the same as the front vents if the ducting is sealed up. Is this common for a 5th wheel and just something I have to live with or does it need to go back to the dealer again?

[therink]

Sledge Hammer wrote:

therink wrote:
I had same issue with my 2013 Keystone Fifth wheel. Then rear most floor vent did not get as much flow as the others. First thing I did was remove all floor registers and placed a small mirror into the duct at each register using a flashlight to see down entire duct to confirm there were no obstructions (all was clear). Using cardboard and foil tape I then fabricated and barrier in the duct at the rear floor register opening so air would no longer flow in the duct beyond the rear register. This appeared to add about 25% flow improvement to the rear without having to restrict flow to the front registers. While I was at it, I did the same at the front register. In my opinion, the extended duct ends served no purpose in my rig but to trap and restrict air flow.
Steve.

I wonder if those extended duct ends you speak of are what heats the underbelly and keeps the water tanks from freezing.

Not in my rig, but should be verified as needed.

[Sledge_Hammer]

therink wrote:
I had same issue with my 2013 Keystone Fifth wheel. Then rear most floor vent did not get as much flow as the others. First thing I did was remove all floor registers and placed a small mirror into the duct at each register using a flashlight to see down entire duct to confirm there were no obstructions (all was clear). Using cardboard and foil tape I then fabricated and barrier in the duct at the rear floor register opening so air would no longer flow in the duct beyond the rear register. This appeared to add about 25% flow improvement to the rear without having to restrict flow to the front registers. While I was at it, I did the same at the front register. In my opinion, the extended duct ends served no purpose in my rig but to trap and restrict air flow.
Steve.

I wonder if those extended duct ends you speak of are what heats the underbelly and keeps the water tanks from freezing.

[Dayle1]

Old-Biscuit wrote:


Back to dealer and have them check that register and duct work with a mirror, camera or by removing the underbelly cover.
It is probably crushed, torn or is not properly attached at furnace.

I don't know about the Heartland, but on many units removing the underbelly will not expose the main furnace duct because it is between the floor joists and hidden by a second layer of Darco fabric.

On the other hand, a poor connection to the furnace is a valid issue. Depends on if there is a single connection for all registers or if the upper bathroom/bedroom registers have their own furnace connection.

[austinjenna]

For me the problem was crushed duct work. We noticed the same thing when going through the inspection, that one vent had hardly anything coming out of it. The dealer removed the bottom of the trailer and the duct was all crushed up.

[therink]

I had same issue with my 2013 Keystone Fifth wheel. Then rear most floor vent did not get as much flow as the others. First thing I did was remove all floor registers and placed a small mirror into the duct at each register using a flashlight to see down entire duct to confirm there were no obstructions (all was clear). Using cardboard and foil tape I then fabricated and barrier in the duct at the rear floor register opening so air would no longer flow in the duct beyond the rear register. This appeared to add about 25% flow improvement to the rear without having to restrict flow to the front registers. While I was at it, I did the same at the front register. In my opinion, the extended duct ends served no purpose in my rig but to trap and restrict air flow.
Steve.

[Old-Biscuit]

Depending on size of furnace MAX CFM from blower can be as low as 140 up to 440.
Suspect you probably have a 30-35000 btu furnace so air flow should be around 350-370 CFM
Any bends can lower air flow. Loose ducts at furnace can lower air flow, crushed duct can lower air flow. Duct work should run as straight as possible.
The air flow should be reasonably the same at all ducts if properly sized and installed.

Back to dealer and have them check that register and duct work with a mirror, camera or by removing the underbelly cover.
It is probably crushed, torn or is not properly attached at furnace.

You should have fired up the furnace at the dealers and had them show you how fine it was. Then you could have had a discuss with them right then and there.

[mdamerell]

Rooms/vents closest to the furnace will be hottest is my experience. You can buy floor vents with adjustable vents to help balance your heat. By shutting off some air flow in the hottest rooms, I was able to balance temps.

[old_guy]

get your self a magnetic floor cover for the vent, they do make them I have seen them, put it over the one in the bed room since you want it to be cooler in there than the living area, test it again and see if you have any improvement. other wise just get something solid and put it over the vent and do your testing. you do want to be careful, these furnaces need to have a certain amount of air flow, you don't want to over heat that furnace.