We have a seasonal travel trailer at a site in Delaware. We went down from PA this weekend to winterize. Spent the night Saturday only to realize over night the furnace wasn't operating properly. the unit would kick in and it sounded normal with the fan motor but there was very little air flow from the floor ducts. The registers were warm but no real air flow. So I assumed since I heard the fan motor that I might have a blockage. The furnace is under the sink counter. I didn't take time to resolve or dive into the issue as we had to leave early to come home. So I took these pictures. It's all I can see from three vantage points. I'll assume by what I see is there must be a opening on the bottom of the unit that lines up with a hole in the floor to the duct work? Are these fastened to the floor or just sitting there? The one end is against the inside wall of the trailer which is the exhaust to the outside. Then it sits on the floor. I'd like to plan on pulling the unit out but I'm not sure what to expect? Are there any diagrams with typical floor duct installation that I could look at? We bought the trailer used and there are not manuals for any appliances. So I'm not even sure of the manufacturer of this? I know I'm not providing much info but that is all I got from the limited time available. Thanks!

Sounds like one of your air ducts might have separated and not allowing the full air flow. Instead, it's blowing under the floor. More than likely, the age of your trailer, the air ducts are that soft aluminum ducts, not the plastic stuff wrapped around a wire spring. I had a 2006 Springdale, 31 feet long, and it had weak air flow from the beginning, because I'm pretty sure the main line running down the middle of the floor was pinched and squished. I was able to run a very long vacuum hose down the duct and found a spot where it wouldn't pass. I kept working the hose. I think the hose eventually pushed its way through the crumpled part, because after that it started blowing better. I also learned the junction points were just simply taped to hold them together. So, it's possible yours separated somewhere. The tape finally deteriorated. I'm assuming it blew stronger in the past?

Before you pull the furnace, one way to check and see what is going on with the ducts is to use an inspection camera. I have one and have used it many times at home and in the RV...You can rent one at Home Depot or most any local tool rental outfit..

On the way home I had a thought. I should have removed one of the block off discs to verify air is pushing from the unit. That thought came after 2 hours of driving:)

I think the camera idea is great ,first hands on is better than taking it apart.

I think a vacuum should be the first tool you use. You can get an endoscope from Amazon for +/- $35.Taking out the furnace would be my absolute last choice, considering it is gasketed to the outside wall and has a gas line connection that has to go back on leak free.

Help with floor ducted furnace, lack of air flow

fairlaniac
Explorer
Nov 12, 2018
Dusty R wrote:
fairlaniac wrote:
On the way home I had a thought. I should have removed one of the block off discs to verify air is pushing from the unit. That thought came after 2 hours of driving:)

Those block off discs, are knock out plugs, and once removed will not stay back in.

Be very careful what you use to push down a duct as it is quite likely you could poke a hole in it.

Dusty

Actually the plugs are discs that have an indexing tab and twist to lock.

That is my concern about poking in the duct work. I assume to access the duct work you must pull up the floor? Lets not go there yet :D
wrktfsh
Explorer
Nov 12, 2018
I used a 35 dollar WiFi endoscope from amazon to ferret out the problem with a weak a/c vent. Turned out that tape sealing the plenum got pushed over that run.
Dusty_R
Explorer
Nov 12, 2018
fairlaniac wrote:
On the way home I had a thought. I should have removed one of the block off discs to verify air is pushing from the unit. That thought came after 2 hours of driving:)

Those block off discs, are knock out plugs, and once removed will not stay back in.

Be very careful what you use to push down a duct as it is quite likely you could poke a hole in it.

Dusty
fairlaniac
Explorer
Nov 12, 2018
Here is picture I found on the internet that is very similar to my trailer. The red line indicates where the duct runs down the center of the trailer and the 90 degree dashed line heads to the furnace under the sink/counter. No sure the easiest way to get the scope in the register opening, down and around to the furnace other than the wire I mentioned in the post above.
fairlaniac
Explorer
Nov 12, 2018
Jack_Diane_Freedom wrote:
I had the same problem in a previous trailer. Plastic wire coil ducting had disconnected from the floor vent. Took vent out of the floor and reconnected. Might work for you.

I have an endoscope that I use on my iPhone. I mainly use it for looking in car engines. I can give it a shot, it has a 5 ft. cord. I may need to put it on a rigid wire to fish it around a corner. I assume the duct directly out of the furnace goes towards the center of the trailer and intersects with the long duct down the center length of the trailer.
Jack_Diane_Free
Explorer
Nov 12, 2018
I had the same problem in a previous trailer. Plastic wire coil ducting had disconnected from the floor vent. Took vent out of the floor and reconnected. Might work for you.
SageCrispin
Explorer
Nov 12, 2018
I think a vacuum should be the first tool you use.

You can get an endoscope from Amazon for +/- $35.

Taking out the furnace would be my absolute last choice, considering it is gasketed to the outside wall and has a gas line connection that has to go back on leak free.
midnightsadie
Explorer II
Nov 12, 2018
I think the camera idea is great ,first hands on is better than taking it apart.
fairlaniac
Explorer
Nov 12, 2018
On the way home I had a thought. I should have removed one of the block off discs to verify air is pushing from the unit. That thought came after 2 hours of driving:)
downtheroad
Explorer
Nov 12, 2018
Before you pull the furnace, one way to check and see what is going on with the ducts is to use an inspection camera. I have one and have used it many times at home and in the RV...

You can rent one at Home Depot or most any local tool rental outfit..