Another poor AC air flow to front bedroom...

Roberson4 · 06-02-2012, 07:48 AM

I have read numerous threads about poor AC air flow from the forward vents. Ours had this problem also. This is what I found out when trying to fix our air flow problem.

Our 5ver has all rectangle duct in the ceiling as far as I can tell. The vents are round with round holes cut into the rectangle duct with the vents screwed into the duct into the ceiling.

I removed the AC cover on the ceiling and this is what I found.

This picture shows there is a piece of insulation board with soft foam insulation stuck to the bottom and side edges. This piece should separate the blower side from the intake side. It is cocked sideways in this picture and this allowed the blower to pump the output air straight into the intake instead of into the forward ductwork.

I straightened up the separator piece and put the AC cover back on and turned on the fan. There was a very noticeable increase of air flow from the forward bedroom AC vent. I forgot to take pictures of how the piece should look in its proper place. So, I removed the AC cover again to take pictures. The piece had already moved out of place. I straightened it again and put vent duct tape around the edges on both sides to hold it in place.

This is how it should look when the separator piece is in the proper place.

This is the same piece in the proper place with vent duct tape helping hold it in place.

therink · 06-02-2012, 08:46 AM

I would additionally recommend to purchase some hvac foil tape and redo all visible seams in the ac plenum. Then remove all ceiling vent covers and retape the spaces between the rectangular duct and the vent opening. This will ensure that no air is getting into the roof cavity. On mine, I also used foam and filled the front and rearmost ends of the main duct (just past the farthest forward and rear ceiling vent openings) to help increase air flow efficiency to these end of the line vents. I hope this helps.

Roberson4 · 06-02-2012, 08:58 AM

Thanks. I will do this also.

Roberson4 · 06-02-2012, 11:42 AM

Quote:

Originally Posted by therink

I would additionally recommend to purchase some hvac foil tape and redo all visible seams in the ac plenum. Then remove all ceiling vent covers and retape the spaces between the rectangular duct and the vent opening. This will ensure that no air is getting into the roof cavity. On mine, I also used foam and filled the front and rearmost ends of the main duct (just past the farthest forward and rear ceiling vent openings) to help increase air flow efficiency to these end of the line vents. I hope this helps.

Did you use the spray foam or pieces of foam to fill the space? I took the vents off the very front and the very back. Looks like I could also benefit from filling these 'voids' in the duct past these vents.

RVUSA · 06-06-2012, 12:39 AM

Get some spray foam and plug the holes on the intake side where the wires come in. That pulls attic air in and lowers the cooling somewhat. Then drop the plastic trim around the vent fans and foam the sides so the opening is sealed from the attic. They leak attic air into the rig like crazy.

I'm surprised your a/c didnt freeze up with that much cold air leaking into the inlet.

mouse101uk · 07-17-2013, 03:20 PM

I recently upgraded from a 28ft travel trailer to a 2013 Hornet 285RKS. In the 10 nights we have camped so far I was less than impressed with the A/C in comparison to our old trailer. On investigation I had exactly the same issue as Roberson4, so went off to a local A/C parts store and got some foil tape. Did all the fixes for the overhead unit and while I was at it blocked the area beyond the last vent at both ends and re-taped around all vents. Airflow seems much better than before (can't test cooling as I only have 15A outside the house), can't wait to go camping again now and experience the difference

Thanks for the tips guys

Nick

labs4life · 07-17-2013, 03:27 PM

Hd the same issue with my sprinter. I fixed the barrier between inlet and outlet and foil taped it good. Then I blocked off the end of the runs past the last vents on both ends. MUCH better airflow throughout the entire unit!!

Essness · 07-17-2013, 04:08 PM

I'm amazed that this particular issue continues to pass QC at Keystone

My first outing with the new camper was terrible. 85 + deg and high humidity. I couldnt cool it down.
Thanks to the folks on this forum, I was able to locate this issue and fix it. I was able to hold 75-76 deg in the camper last Monday when the outside temps were high 90's.
And, it cools significantly quicker!

Bob Landry · 07-17-2013, 04:47 PM

This appears to be a problem with almost every Keystone trailer. This information needs to b a sticky.

Robby9 · 07-21-2013, 07:31 PM

Wow! That's really shoddy work from Keystone.

Thanks for posting the pictures. That will really help me check my rig, since I'm not happy with the cooling either.

I read on another forum that the dead space at the end of a duct run is intentional. It's supposed to somehow equalize the airflow to all of the vents on that run.

**JRTJH** · 07-22-2013, 05:08 AM

Quote:

Originally Posted by Robby9

Wow! That's really shoddy work from Keystone.

Thanks for posting the pictures. That will really help me check my rig, since I'm not happy with the cooling either.

I read on another forum that the dead space at the end of a duct run is intentional. It's supposed to somehow equalize the airflow to all of the vents on that run.

There is an "over-run" at the end of the ductwork. The theory I've heard is that it allows air to flow past the furthest duct opening and acts as a buffer to prevent "air rush sounds at the vent. Apparently, in some units there can be a whistle if the duct run is terminated at the vent. The extended ducting apparently stops this noise. On mine, I put a piece of foam weatherstripping in the duct and used a stick to push it to the end of the duct run. It stopped the air leak and there's no noise. Since I didn't try to plug the duct at the last vent, I don't know if there would have been any increased air noise or not. Of course, with the A/C sitting 5 or 6 ft away, I don't know what "air rush noise" would be greater than the sound of the compresser and fan in the main unit. Noise seems to be a part of A/C operation in small closed spaces anyway.

EricLynnAllison · 07-22-2013, 05:32 AM

I had the exact same issue with my Raptor. Used a lot of foil tape to seal everything up.

Bob Landry · 07-22-2013, 08:58 AM

Quote:

Originally Posted by therink

I would additionally recommend to purchase some hvac foil tape and redo all visible seams in the ac plenum. Then remove all ceiling vent covers and retape the spaces between the rectangular duct and the vent opening. This will ensure that no air is getting into the roof cavity. On mine, I also used foam and filled the front and rearmost ends of the main duct (just past the farthest forward and rear ceiling vent openings) to help increase air flow efficiency to these end of the line vents. I hope this helps.

Did all of that on my Outback also. It's hard to imagine that anyone who has been reading this forum for any time at all hasn't figured out to do all of this. This is a pretty common problem with Keystone manufacturing that keeps popping up.

Quad · 07-22-2013, 09:16 AM

Amazing the lack of QC there is on these units.

Terrydactile · 07-22-2013, 11:57 AM

I did the same repairs to the plenum, duct ends and vent cut outs on my Passport back in 2008. Its been a problem for a long time.

**JRTJH** · 07-22-2013, 12:31 PM

Just thinking out loud, but Keystone may not consider it a "quality issue" They may well have crunched the numbers and come to the conclusion that it's cheaper to "throw the ducting" together, ship it out to the dealer for sale and "IF/WHEN" the customer complains, pay the dealer to repair it. So many of us just "tape it up and let it go" that it may be that Keystone's conclusion is correct. Why spend a lot of money on an issue that the customers don't complailn about, and the few that do, just pay to fix it under warranty.

After all, isn't "quality control" about satisfied customers? So, if there's no "rush to complain" then Keystone "must be doing it right" (at least the feedback would trend that direction).

As I said, just thinking out loud.

Quad · 07-22-2013, 04:08 PM

Would they even fix it under warranty if that's is their standard they ship them all out it??? (Minus the baffle falling over)

therink · 07-22-2013, 04:18 PM

Quote:

Originally Posted by JRTJH

Just thinking out loud, but Keystone may not consider it a "quality issue" They may well have crunched the numbers and come to the conclusion that it's cheaper to "throw the ducting" together, ship it out to the dealer for sale and "IF/WHEN" the customer complains, pay the dealer to repair it. So many of us just "tape it up and let it go" that it may be that Keystone's conclusion is correct. Why spend a lot of money on an issue that the customers don't complailn about, and the few that do, just pay to fix it under warranty.

After all, isn't "quality control" about satisfied customers? So, if there's no "rush to complain" then Keystone "must be doing it right" (at least the feedback would trend that direction).

As I said, just thinking out loud.

10-4 on that. I believe there are many areas such as this that the manufacturers (not just Keystone) take this approach. Let the dealers and customers work out the QC issues.

TTCAMPER · 09-08-2013, 06:45 AM

Just got done taping up the inside of the blower area, found that the whole access hole for air to go through was not even open, that explains not much air being blowin in the back kids area.
After taping all the corners and seams turned unit on and I got 10 times the amount of air blowing out the back vent.
Thinking of putting a block off at the back so it forces air down instead of to the back wall of the camper.
Will see if helps cool better in a couple weeks.

therink · 09-08-2013, 07:30 AM

[QUOTE CAMPER;95156].
Thinking of putting a block off at the back so it forces air down instead of to the back wall of the camper.
Will see if helps cool better in a couple weeks.[/QUOTE]

I did this at both front and rear vents and it helped quite a bit with airflow. I also did this with the floor heat vents have as the duct also continues past the vent locations.

You may also like: