Tuesday, September 27, 2022


Ask Dave: No airflow to RV’s bedroom heat vent. How do I see what’s wrong?

Dear Dave,
We think there are two issues that need to be addressed. But first, there is no airflow to our RV’s bedroom heat vent. Can we open the underbelly cover to see the plumbing and duct system? It appears sealed, but there are larger bolts. —John

Dear John,
From the videos and information I could find online, your 2021 Crossroads Hampton 380RKS has heat vents in the floor similar to residential, rather than mounted to the bottom side of cabinets and under the sofa. Looking at other vents in the layout, they are not in a straight line. So I would assume that you don’t have a “plenum” that runs from the furnace on the underside of the floor supplying the vents. Rather, I would assume it’s the old “elephant trunks”—as we called them—that are corrugated tubing going to the vents with an elbow. Here is a sample of one that is mounted under a sofa.

Why you’re not getting airflow to your RV’s bedroom heat vent

To determine why there is no airflow to your RV’s bedroom heat vent, the first thing I would do is remove the vent in the bedroom from the inside and see if there is room to pull the hose up. Otherwise, you should be able to see down inside and tell if it was connected or not. If it is connected, then you have a kink or loose connection downstream somewhere.

Something we’ve done in the past with an enclosed underbelly, if we can tell the connection is off, is cut a square in the corrugated plastic material on the bottom directly under the area we need to work on. You can purchase this material at any dealership or generally a home improvement store. Cut a piece slightly larger than your square, silicone all around the edges, and screw it to the underbelly material and let it sit for a couple of days. Some people have even applied Eternabond around the edges.

Stay out of the underbelly

You can remove the underbelly material but typically that is a very hard job. There is a ton of expandable foam around the dump stations, drain valves, and sometimes the edge. Check to see which method is easier in figuring out why there is no airflow to your RV’s heat vents. Good luck!

Dave Solberg is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club.

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Thomas D
5 months ago

Some electricians and plumbers have scopes that could be put into the heater hoses and observed by a small screen. Or you could go to harbor freight and buy one (everyone needs more toys, right). That way you could get an idea what or where the trouble lays. I’ve cut plenty of the coraplastic fixing factory goof ups. No big deal. And most of the time I used the same piece to repair the hole. Just cut 3 sides and bend it out of the way. Join back together with zip ties.

5 months ago

I had the same issue in our 2017 Forest River 34QS. Actually it was blowing air, but very little, I discover the problem when I was investigating where my wires were going from my solar charger. I could see all of the  corrugated tubing coming from the heater & one of them wasn’t totally connected. After securing it, we had full heat to our bathroom! Never did find those solar wires!

5 months ago

If you cannot pull the end of the duct out or there is an elbow you can’t ‘see’ around put a small cell phone in there and use the camera to take a video around the corner.

Or use a flexible camera (bore scope, endoscope etc). You can get one that connects to your smart phone for $20-$30.

5 months ago

Dave’s answer is ok if the line is straight. If it’s not which is my problem, the only recourse is to remove a portion of the underbelly. Thisvi am not going to do, not take it in to a dealer. it would cost a fortune.

5 months ago
Reply to  John

Or, as Tim said above, use a bore scope that attaches to your smartphone or tablet and feed it through the corner (s). I bought one and love it for scoping out tight spaces in the RV and around the house and shop.

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