A/C ????

[Sdgood1]

2014 3150RL 2 A/C units. Second trip for the new to us ride. Went to LV for a few days, temps running in mid to upper 90’s. In the morning with the sun on the back and drivers side, the ducted A/C barely kept it in the upper 70’s. Of course the bedroom stayed nice. Reading some of the posts on here that’s about normal. Any input?? Solutions??

[Texan]

Most likely your return air vents in the den on the ceiling are partially collapsed and so not working properly. I cut me 1 1/4'' diameter pvc pipe 9'' long and installed them in the return air ducts to open them up. I used 2 in each vent where some have used 1. I stuck my pipe in the vent parallel with the vent then turned the pipe and inserted it in the duct toward the center of the rv. You can push it the whole length of the pipe or more up in the duct and this will help the return air work much better. I am sure there are some other ideas others may have but this is something many on this forum have done that is very easy to do for less than 10 bucks.

[ebds2019]

Originally Posted by Texan

Most likely your return air vents in the den on the ceiling are partially collapsed and so not working properly. I cut me 1 1/4'' diameter pvc pipe 9'' long and installed them in the return air ducts to open them up. I used 2 in each vent where some have used 1. I stuck my pipe in the vent parallel with the vent then turned the pipe and inserted it in the duct toward the center of the rv. You can push it the whole length of the pipe or more up in the duct and this will help the return air work much better. I am sure there are some other ideas others may have but this is something many on this forum have done that is very easy to do for less than 10 bucks.

OK folks I have read about this mod several times and finally decided to look into it more seriously. But still having some understanding issues. I have a 3810MS with an arched roof. A little while ago I took the cover and filter off one of the returns in the living room. I measured the distance from the top of the return to the bottom of the return right at the air register. It measured about 1". I don't have a ladder with me so I can't get up high enough to actually look into the register (going to try to use my phone camera with flash later).

I am confused. If the vent measured 1" at the opening and the pvc you are all recommending is 1-1/4" how does that make much of a difference? What am I missing here? Where is this closed up vent supposed to be?

Also, in my 3810MS there are two A/C units, one in the living room and one in the bedroom. If I turn on the living room unit there is also some cool air coming out of the bedroom vents. How can that be? Aren't they two separate cooling subsystems?

[Mikendebbie]

I have a 2018 model. Below is a screenshot from the sales brochure. These ducts look semi-rigid like duckboard. This shows the supply side. I have no idea if return ducts are similar. Are these the ducts that have the collapse issue?

[Ram Montana High Country]

Originally Posted by ebds2019

OK folks I have read about this mod several times and finally decided to look into it more seriously. But still having some understanding issues. I have a 3810MS with an arched roof. A little while ago I took the cover and filter off one of the returns in the living room. I measured the distance from the top of the return to the bottom of the return right at the air register. It measured about 1". I don't have a ladder with me so I can't get up high enough to actually look into the register (going to try to use my phone camera with flash later).

I am confused. If the vent measured 1" at the opening and the pvc you are all recommending is 1-1/4" how does that make much of a difference? What am I missing here? Where is this closed up vent supposed to be?

Also, in my 3810MS there are two A/C units, one in the living room and one in the bedroom. If I turn on the living room unit there is also some cool air coming out of the bedroom vents. How can that be? Aren't they two separate cooling subsystems?

IMHO - get a work platform of ladder to easily work from. once up there: see if you can easily push the top of the duct up to increase the space by 1/4". If it opens up, that gives you 25% more space. The return side is more of an issue. On the pressure side, limiting obstructions is important to not hinder flow. kinda like a rock in a stream


If you are a gadget person, get a bore scope to run off your phone. This allows you to see all sorts of places normally not accessible .

[mtlakejim]

Originally Posted by ebds2019

OK folks I have read about this mod several times and finally decided to look into it more seriously. But still having some understanding issues. I have a 3810MS with an arched roof. A little while ago I took the cover and filter off one of the returns in the living room. I measured the distance from the top of the return to the bottom of the return right at the air register. It measured about 1". I don't have a ladder with me so I can't get up high enough to actually look into the register (going to try to use my phone camera with flash later).

I am confused. If the vent measured 1" at the opening and the pvc you are all recommending is 1-1/4" how does that make much of a difference? What am I missing here? Where is this closed up vent supposed to be?

Also, in my 3810MS there are two A/C units, one in the living room and one in the bedroom. If I turn on the living room unit there is also some cool air coming out of the bedroom vents. How can that be? Aren't they two separate cooling subsystems?

The "quiet air" return air ducts will only be on one unit (usually the living room unit). The ducts will collapse in the middle about half way to the center of the unit where the actual AC unit is located. It will be particularly noticeable when the unit is running and pulling a bit of vacuum on the ducts. So the short answer is you will have to get on a step stool and look down the vent to see what everyone is talking about. No real surprise as the ducts are not much heavier than a cereal box with the weight of a roof on top of them!!!

The discharge ducts are tied together with the AC units on either end of the unit. So yes, you will get some air out of all the vents even with only one unit running. There should be an option on the AC unit that does not have remote "quiet air" return ducts to dump the discharge air directly out of the unit without it going to the vents. That feature is handy to cool off the bedroom quickly. We leave the dump cracked open just a tad to make it cooler while sleeping.

Trust the folks on here and just do all the mods. They will work.

[Mudchief]

You need to do what Texan said above. I did that and it made a difference.

[DQDick]

Since we summer in Kansas we made a number of changes. First we did as suggusted above. Then we took the supply ducts off the ceiling and cut every other fin off to improve air flow and before we put them back we cut the sleeve down so it didn't protrude into the air ducts anymore. Both of those things made a real difference. Last we gave up an added a third AC and wired it so it can run at the same time the other two did.

[Ram Montana High Country]

Ditto advice above - the air return can easily be done there - opening the vents like DQ mentioned helps - this is harder to do at a campsite, might just try removing 4 of them - 2 in bedroom and 2 in main cabin just to get you running but do the air return first

[McIver]

Not too long ago I read that someone had made modifications to the vents on the units themselves. Testing with a meter it seems the lovers on the units restrict air flow significantly. He cut them out and replaced them with wire screens. The modifications allowed the units to vent more efficiently and therefore run much more effectively. Simple fix.

[Ram Montana High Country]

Originally Posted by McIver

Not too long ago I read that someone had made modifications to the vents on the units themselves. Testing with a meter it seems the lovers on the units restrict air flow significantly. He cut them out and replaced them with wire screens. The modifications allowed the units to vent more efficiently and therefore run much more effectively. Simple fix.

my only thought is the louvers provide air direction - good for when an individual may not want air directed at them and also would aid in stirring up the general air - food for thought. and screen might actually slow down air movement … not sure - would need an AIR Expert

[MidMOTraveler]

Just pop a couple of the directional vents off. You will be amazed at the difference.
I did do the pvc fix in the return air. But we had another issue with the back unit not being mounted directly over the opening. Had some water coming through the back return vents, mobile service found and repaired. Submitted pictures and bill to Keystone and they reimbursed.
That really made a difference!

[1retired06]

Originally Posted by Sdgood1

2014 3150RL 2 A/C units. Second trip for the new to us ride. Went to LV for a few days, temps running in mid to upper 90’s. In the morning with the sun on the back and drivers side, the ducted A/C barely kept it in the upper 70’s. Of course the bedroom stayed nice. Reading some of the posts on here that’s about normal. Any input?? Solutions??

Not normal. Blocked/collapsed ducting a common problem. Follow some of the posted recommendations and you will feel a difference.

[Sdgood1]

Thanx all. Home now , so will really look into the problem and try some of the fixes.

[McIver]

The vents on the roof unit are the ones I am talking about.

[Texan]

I forgot to mention you can buy the air-ducts that have the vent slats further apart and are directional at PPL. This allows more volume of air. I believe they are about 8 bucks each. I installed these on mine. You can also add a couple of extra ducts to bring in more air at a particular area. When you are running in the mid to upper 90's you tax the limits of the a/c. If you can keep the inside 20 degrees cooler than the outside then consider yourself lucky.

[Chasnracin]

What is PPL?

Originally Posted by Texan

I forgot to mention you can buy the air-ducts that have the vent slats further apart and are directional at PPL. This allows more volume of air. I believe they are about 8 bucks each. I installed these on mine. You can also add a couple of extra ducts to bring in more air at a particular area. When you are running in the mid to upper 90's you tax the limits of the a/c. If you can keep the inside 20 degrees cooler than the outside then consider yourself lucky.

[Ram Montana High Country]

Originally Posted by Chasnracin

What is PPL?

https://www.pplmotorhomes.com/rv-parts-rv-accessories

[Woodworker]

Does anyone have some photos of this procedure? I can't quite wrap my head around this. We are spending a couple of weeks in Branson. It's hot. Need relief.
Thanks.

[MidMOTraveler]

Steve a quick help not the fix is just pop off the vent covers. This allows so much more air flow. They are kinda hard to get off the first time and you’ll think it going to break but will come off. Just pull down and you’ll notice that some spots move some don’t . Put your fingers on either side and pry down.
As for the pvc in the return air ducts take the cover and filter out then take the plastic mounting down.
Insert a pvc pipe and turn as you do this the return duct only runs cross ways, push to the sides carefully so as not to damage the duct. Do this to both sides so 8 pieces of pipe are needed.
I wish we could post pictures from I phones on this site, don’t have a computer.