Collapsed return air vents

Ddubya · 07-25-2018, 01:46 PM

I have done the mods on my air vents to seal them and have considerably more air flow so I decided to check out the return air plenums. Now I wish I had not opened up this can of worms.
When the return air plenum in the living area was installed (I use the term loosely) they cut the entire bottom of it off so that the air is totally exposed to the back side of the ceiling. Instead of it being a sealed rectangle it is three sided. Needless to say it is not sealed where it comes in contact with the back side of the ceiling so the hot air in the attic area is sucked into the return air.
On top of that they ran electrical wiring under the sides of the plenum where it contacts the ceiling making an even larger area for attic air to be sucked into the return system.
In addition to that, the plenum is collapsed in the center so even if it were sealed it would still severely restrict the return air flow.
I have read of people using 1 1/2 inch PVC pipe to open up the collapsed areas but that will do little due to the gaps between the plenum sides and the ceiling.
Waiting on solutions from you very smart RV owners.

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5J's · 07-25-2018, 02:01 PM

Any chance you're still under warranty?

SC Dreamer · 07-25-2018, 02:45 PM

Block those off, open vents on a.c. to dump directly and use a fan to circulate air around inside of camper.

Ddubya · 07-25-2018, 02:46 PM

Out of warranty. Doubt Keystone would do anything anyway.

5J's · 07-25-2018, 04:23 PM

You might try them anyway.

ChuckS · 07-26-2018, 05:59 AM

If it where me I’d try inserting two pieces of the PVC pipe and see how it does.

Keystone Alpines are not perfect and I’d bet a good cup of coffee that none of the other brands are either.

If you are getting adequate cold air flow after sealing your AC ducts and blocking off the furnace returns that’s really all you are after.

My 2014 has lots of “why’s this done this way” items but in the long run they work so I don’t try to rebuild the whole RV.

Only other recourse for what your after is drop the entire ceiling. And there’s no way I go to all that trouble.

Ddubya · 07-26-2018, 06:38 AM

ChuckS, The PVC trick is what I was thinking about but I contacted Keystone and they told me that although it is out of warranty they may cover a repair. We will see.

Pull Toy · 07-26-2018, 12:25 PM

Let us know how you make out

Good Luck,

5J's · 07-26-2018, 02:50 PM

I was hoping for that response. Good luck.

E Rod · 07-26-2018, 03:11 PM

I have a 2017 Alpine 3660FL. I added additional vents and return air vents. The return air are directly under the a.c. unit. Ac works much better now. It should work for you as it did on my alpine. U could just block off the old return air ducts.

Ddubya · 07-27-2018, 01:00 PM

E Rod, My return air vents are on each side near the walls in line with the A/C unit. Is that where yours were? Did you add two more returns just closer to the A/C unit?

E Rod · 07-27-2018, 01:07 PM

Mine are on each side as well. I added one additional in center at each unit. I also added 7 additional air vents. 2 in bed room, 3 in kitchen and 2 in living room . Made a HUGE difference.

GaryAnita · 07-28-2018, 07:26 AM

I have seen some of the threads regarding the A/C ducts collapsing along with the return air ducts. I have a front kitchen 5th wheel and I am having a hard time cooling it. It has the window in the front cap. I have put the foil insulation in the inside of that as well as the same on the rear double windows in the rear bedroom. The rear unit seems to cycle continuously until it gets the bedroom cooled of and then cuts off as it should. The front unit will eventually catch up after dark and cut off. I have seen it get up to 92 degrees in there during the middle of the day with both units running. Any suggestions?

E Rod · 07-28-2018, 09:44 AM

Check your duct for debris or blockage. I used an inspection camera. Also added extra vents and return air as written in above replies. I only had two vents in living room, two in kitchen and two in bed room. I added 2 to living room right as the air exits the unit into the duct and added 2 to bed room and did same as the front living room. Added 3 to kitchen and added a return air grille right underneath the a.c. unit. Made a huge difference. Other than very hot days i can run one a.c. instead of two.

Ddubya · 07-28-2018, 10:10 AM

GaryAnita, Pull all of the vents off and see if they are properly sealed where they meet the duct. Most are not. Use aluminum HVAC tape to seal them. That will improve your air flow.
You can use your Cell phone in Video mode with the light on to look in the ducts if you do not have an inspection camera.

Barseven · 07-29-2018, 03:15 PM

Quote:

Originally Posted by E Rod

I have a 2017 Alpine 3660FL. I added additional vents and return air vents. The return air are directly under the a.c. unit. Ac works much better now. It should work for you as it did on my alpine. U could just block off the old return air ducts.

E-ROD looks like we ordered the same vent covers you have. We haven't installed them yet, but I was wondering if you had to remove the base from the old vents or were you able to use the new vent covers with the old base?

E Rod · 08-02-2018, 12:39 PM

Quote:

Originally Posted by Barseven

E-ROD looks like we ordered the same vent covers you have. We haven't installed them yet, but I was wondering if you had to remove the base from the old vents or were you able to use the new vent covers with the old base?

I removed them completely. Taped up the gap between ceiling and duct. These vents have much better airflow than the original.

RayT · 08-02-2018, 04:07 PM

What vent covers are you using?

TIA

-Ray

E Rod · 08-02-2018, 08:21 PM

Quote:

Originally Posted by RayT

What vent covers are you using?

TIA

-Ray

Not sure on brand. Got them through Amazon like $6 a piece. I added 7

louielouieohoh · 08-07-2018, 07:52 AM

Quote:

Originally Posted by E Rod

Check your duct for debris or blockage. I used an inspection camera. Also added extra vents and return air as written in above replies. I only had two vents in living room, two in kitchen and two in bed room. I added 2 to living room right as the air exits the unit into the duct and added 2 to bed room and did same as the front living room. Added 3 to kitchen and added a return air grille right underneath the a.c. unit. Made a huge difference. Other than very hot days i can run one a.c. instead of two.

Erod ... there's a few of these vents on Amazon. I want to make sure what I buy will fit in my "current" vent locations. Can you please take a picture and give us some dimensions, please?? Maybe give us the link to the Amazon item too, please?

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