Interesting RV A/C trick/hack/fix

I was doing some cleaning of the return air filters for the A/C. After removing the filters and housings I noticed the duct work to have collapsed to nearly close off the duct in spots. I checked the A/C outlets as well and found a similar situation. Since these are cardboard, there’s not much rigidity to the ducts. This probably explains the low air flow from some of the vents further away from the A/C unit.

I’d heard about some people inserting PVC piping into the ducts to open them back up, but that can be a bit challenging since the openings are small and the PVC doesn’t bend. I thought about maybe using a smaller sized “pool noodle” since those could more easily slide into the ducts.

As I was searching for options I ran across this tip from a fellow Vanleigh owner: RV low airflow fix . It’s pretty ingenious in its simplicity, and quite inexpensive (less than $10). I picked up a bag of practice golf balls (the type with holes) and will be placing them in the ducting to keep them from collapsing.

I’m thinking this simple trick should improve the A/C airflow and efficiency. Once I’ve had a chance to see them in action I can share the results.

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I have heard of many corrections that folks have tried, from pool noodles, pizza box holders and floral foam blocks. The PVC is the option I went with. I cut the 1.5 OD PVC into 5.5" sections that allowed it to pop up into the holes of the returns. This has worked fairly for me over the past 3 years. Taking a large section and scoring it at 5" so it “folds in” will allow you to open up the ducts all the way down. Vanleigh placed seems in random places that will also collapse midway and not just at the return points.

Last year while touring a keystone facility in Elkhart I ran across the same ductwork that VL used being used in the Montanas. They however patented a plastic insert that fits into the ductwork that keeps it rigid and from collapsing. They have been allowing other manufacturer’s to use this same method and saw it used in subsequent plant tours I took. Although this would be impossible to retrofit.


Montanaduct

Thanks for that info Ryan. I hadn’t thought about scoring the PVC as you indicated to allow for longer runs, that’s pretty cool! If the golf ball experiment doesn’t return the results I’m hoping for, I’ll probably duplicate your solution. Did you place the PVC in the center or offset in the ducts?

That keystone modification sounds like the best solution on new installs. Too bad it wouldn’t be viable on existing models without a major teardown.

Interesting solutions for sure. Another option to throw into the search fodder mix: https://www.irv2.com/forums/f44/2020-vilano-320gk-a-c-issue-546533-4.html#post6276426

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Thanks Beerdude for link to other forum!

I have 3 ac units in the 2021 Beacon 41FLB. The floor plan has 3 steps up to rear headroom & 3 steps up to front living room.

Originally had 3 Furrion heat pumps but when bought it second hand the middle & front heat pumps were shot & replaced with 2 Furrion FACR 14SA-BL 14.5 BTU AC. This due to supply chain issues for heat pumps being unavailable!

The galley is down at step entry level & has more cubic feet to cool plus the ceiling vents are different than the other ceiling vents which are louvered & galley vents are not.

With all 3 units on & in high fan mode seems to cool ok. However if just the middle unit is on I don’t feel any air out of galley ceiling vents. Also I’ve not figured out how to remove them - the nut does not turn!

I’ll check to see if there is a collapsed vent in galley ceiling & report back

The cold air duct is not blocked. Photo is from bedroom vent to the front living room vent. Seems ok & no collapse

However the return vent in galley is collapsed between living room & bedroom. So I have to select a method to open it plus add a deflector in galley cold air vents if I can get the covers off!

Hey Taj, those cap nuts on the metal air outlets and returns should turn. They can be a little difficult to remove as I found out when I removed a couple of mine.

I found if applying downward pressure while turning it helped break them free. One thing to note is the way they were attached makes it even more difficult to re-assemble. Those cap nuts attach to a threaded bolt that is attached to a metal cross brace in the duct. On mine that threaded bolt wasn’t held onto that cross brace with anything other than gravity, which made it nearly impossible trying to reattach the cap nut. I’d suggest wrapping the bolt head with tape (or maybe gluing) where it attaches to the cross brace to hold it in place while reattaching the cap nut. Once the nut is started on the threads it’s much easier to get it secured down the rest of the way.

They do look nice, but there are a PITA to remove and put back IMO. At least there are only 4 of them! :wink: .

Thanks for a great tip Stuart!

I’m always a little nervous about cranking on cap nuts.

Bob

I glued mine. Now replacing the cap nuts is no issue. I also only finger tight the cap nuts.

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That metal insert looks exactly like what Tish put into my return lines to open them up.

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Has anyone considered using PEX piping to create the space in the return line? It may be flexible enough at the 1.5" diameter size to go through the vent hole and perform the same function as the PVC pipe sections. A guide string could be fished from one vent to the other to help guide the PEX and make it lay against a side of the existing duct. Once in place, the existing duct should hold it in position. I may try this as I have found my return ducts to be closing up.

That could be another option as the PEX is more flexible than PVC. To properly support the duct it should really be down the center as that seems to be the point of collapse and contact that I’ve seen in our ductwork.

Might also want to make sure when placing it in the ducts that the flexibility of it doesn’t end up curving from one side to the other which would end up blocking the duct off.

I considered the curve of the PEX in the size to fit the duct, you can purchase straight 10’ sticks through AMAZON. I’m not sure there is a good method to straighten the rolls of PEX that are also available. I did cut some 1.5" PVC to 4" lengths and stuck in the return duct right beside the intake vents to see how that works. I need to buy a boroscope/endoscope to really get a look down the duct to see where the pinch points are located. I will also look at the AC discharge duct to see what condition it is in and determine if anything needs to be done to it also.

We have a 2023 Ambition 399th. There is almost no airflow from the rear a/c unit to the garage. Nor does any heat flow back there. I am new at this so i am not sure what to look for, or how to open the vents.

Check all of your ducts by pulling off the ceiling vents. The adjustable vents on the curb side are the supply and the non adjustable on the street side are the return. It is common for the return vents to be collapsed as you may have gathered from this thread. Most use 5" pieces of 1.5 outer diameter PVC on both sides of the vent to hold it open. I have seen many other things used from floral foam to pizza holders.

Also check in those vents for separation / openings in the ducting. I used an inspection camera / scope to run up and down checking for openings - most I was able to address. I was replacing the inner bezel for the bathroom fan and found that they completely cut the ducting open and the supply air was escaping into the attic space. You can see from this pic that it is cut open the length of the fan.

I cant say much about the heat but in our Grand Design toy hauler there was a vent just at the step into the garage area. That was hooked to ducting that ran in the underbelly up to the heater. We never had good heat in our garage in that unit. Not sure how Vanleigh ran that in the toy haulers but seem to recall it was in the wall.