A/C not keeping up

sparky1266 · 07-10-2017, 01:15 PM

Greetings

We have a 2014 3970 with an epic all-weather package. It has two air conditioners with one being in the bedroom and the other one for the main area. We are finding that the main air conditioner does not keep up at all. Even in temperatures that are around 25 Celsius it has a difficult time cooling the area down. Right now we have a bit of a heat wave up here where we are sitting at 35 to 37 Celsius and we practically have to sleep in our vehicle for any measure of comfort. We have cleaned the coils out up on top but they were not dirty. We have cleaned the return air intakes which were a little bit discolored but nothing serious for being plugged. Does anybody else have this problem? The one in the bedroom is overkill as it is very loud and throws a bunch of cold air which is obviously working properly. Is there anything else I can check to see why this main air conditioner is not functioning like I think it should? Or is this just a design flaw in the engineering process?
Thanks,

Patrick

RVNevada · 07-10-2017, 03:02 PM

patrick, unless your ready for some work......Anyway, a lot of us have taken the A/C's off and retaped the box, they did a poor job and your cold air isn't getting to where you want it to go, the cold air is just going up in the unsealed ares of the roof. There are 4 screws to remove it, just make sure you have a good cover for your roof, so you don't damage the roof, and as you move it, be careful of the wiring, double check the wiring when you move it back

ATCguy · 07-10-2017, 04:05 PM

Quote:

Originally Posted by RVNevada

patrick, unless your ready for some work......Anyway, a lot of us have taken the A/C's off and retaped the box, they did a poor job and your cold air isn't getting to where you want it to go, the cold air is just going up in the unsealed ares of the roof. There are 4 screws to remove it, just make sure you have a good cover for your roof, so you don't damage the roof, and as you move it, be careful of the wiring, double check the wiring when you move it back

Yep, most of us have had to do this. Remove the unit from the roof, clean up & retape the entire box (we've found wood shavings, trash, and even empty soda cans left in there!)... and then inside your rig, remove all of the duct vents, and retape all of those (including the one in the bath, garage, and bedroom).

Even then, though... I find in seriously hot weather, that running both A/Cs is necessary. I usually keep the bedroom A/C thermostat set 10 degrees (F) lower than the main, and the bedroom door open.

Hvacman · 07-10-2017, 09:50 PM

I used spray foam to repair the leaking ductwork along with cleaning out all the sawdust. In addition on my 3970 I cover the living room windows on the inside with the foil type sunscreen material. Makes a difference. Good luck

joebedford · 07-11-2017, 01:48 AM

Welcome to the club. Re-tape everything and remove construction debris from ducts. You may need to put sections of PVC tubing in where the duct has collapsed. I added a new vent above my easy chair in the LR and that helps a lot (subjectively).

otr_pwc · 07-11-2017, 07:45 PM

We tried retaping and resealing. It helped. What really made a difference was blocking/taping almost all the ductwork ports at the a/c unit and just letting the cool air exit the a/c unit directly into the main living area like a non-ducted unit. We cut out the sliding baffle on a ducted cover to allow maximum air to exit. On our trailer it significantly increased cooling. Can put it back to stock by simply removing some tape and replacing the ceiling cover ($25).

We did use an aluminum baffle to force some air into one duct that fed the bathroom (we taped off the remaining ducting). We bent the baffle slightly to adjust the amount of air fed into the bathroom. Works perfectly.

Yes, a bit noiser, but very effective. YMMV.

You can test the effectiveness of doing this on your unit without risk by removing the ceiling cover and temporarily blocking the existing ductwork and taping some cardboard where the ceiling cover would normally go.

joebedford · 07-12-2017, 12:47 PM

He's got a 3970. Doesn't that have that ceiling thingy that prevents direct access to the LR A/C? (like my 3950)

Sinecure · 07-12-2017, 01:58 PM

I'd love to see some pictures of this if you have some.

Quote:

Originally Posted by otr_pwc

We tried retaping and resealing. It helped. What really made a difference was blocking/taping almost all the ductwork ports at the a/c unit and just letting the cool air exit the a/c unit directly into the main living area like a non-ducted unit. We cut out the sliding baffle on a ducted cover to allow maximum air to exit. On our trailer it significantly increased cooling. Can put it back to stock by simply removing some tape and replacing the ceiling cover ($25).

We did use an aluminum baffle to force some air into one duct that fed the bathroom (we taped off the remaining ducting). We bent the baffle slightly to adjust the amount of air fed into the bathroom. Works perfectly.

Yes, a bit noiser, but very effective. YMMV.

You can test the effectiveness of doing this on your unit without risk by removing the ceiling cover and temporarily blocking the existing ductwork and taping some cardboard where the ceiling cover would normally go.

calewjohnson · 07-15-2017, 10:04 AM

I went a step further with the air intake. I am not one to shy away from cutting and modifying stuff. After seeing how crappy the filters were, I cut both ceiling returns and boxed them in such that they can take a regular home 12x12 filter. That alone increased the amount of air coming from the main AC unit. Think, the system cannot push out more air that it breathes in.

Also pulled down all the vents, cut them larger, taped them, and installed some that provide directed air.

I have also added another vent in the main living area.

I have used Reflectix on all my windows. Put pieces in each window, then velcroed a single large piece on each window. With IR thermometer, window is 120F, single layer Reflectix 95F, with second layer Reflectix 80F.

We have three AC units, I keep the main unit at 76F, bedroom at 73F, and garage at 75F. The trailer stays comfortable and the units all cycle on/off on Maryland 95-100F days, in the direct sun.

If someone could figure out how to bypass the stupid thermostat algorithm to allow the fan to blow on high when the AC turns on, that would be great. In AUTO, the fan blows low...there needs to be a 6F split between actual and demanded air temperature.

When I leave the trailer for the weekend, I turn all off, when I come home, it is 95-100F inside....turning all three units ON, with the fans manually set to high will put the trailer into the 70's within an hour.

Cale

poplejeune · 07-15-2017, 05:23 PM

Quote:

Originally Posted by joebedford

He's got a 3970. Doesn't that have that ceiling thingy that prevents direct access to the LR A/C? (like my 3950)

Im with Joebedford, I have a V-3950, and have a center Console over sink Island, that has light fixtures hanging down from it. No way for A/C to dump straight into living/kitchen area. So how did you remove to get to A/C?

calewjohnson · 07-15-2017, 05:49 PM

Have to remove it from the roof side. The lag bolts are probably less than adequate, due to the clowns at the manufacture over tightening them. I went up one size and all is right with the world now.

Cale

CSCLARK · 07-16-2017, 11:28 AM

Quote:

Originally Posted by calewjohnson

I went up one size and all is right with the world now. Cale

Ditto on 1 size over lag bolts. Still curious Cale how you cut the extra vent in the living! Did you just mark in between the front and back vent and stay in the middle of that duct chase, then cut right next to the island light drop down? Or did you somehow remove the light fixture island?

calewjohnson · 07-16-2017, 01:05 PM

Quote:

Originally Posted by CSCLARK

Ditto on 1 size over lag bolts. Still curious Cale how you cut the extra vent in the living! Did you just mark in between the front and back vent and stay in the middle of that duct chase, then cut right next to the island light drop down? Or did you somehow remove the light fixture island?

I will send pictures when I get back this evening (in Baltimore now), but I took two vents off and used a chalk line to mark the edges of the holes, then used a hole saw. My luck, I hit part of the "frame" that went across the ceiling (just nicked it). Taped it all up and it looks factory. I need to put one in the loft also, as it gets stuffy up there.

Cale

ATCguy · 07-16-2017, 04:07 PM

Quote:

Originally Posted by CSCLARK

... Did you just mark in between the front and back vent and stay in the middle of that duct chase, then cut right next to the island light drop down? Or did you somehow remove the light fixture island?

Just a thought... we all have different model rigs with different floor plans. You've got an Island light, many others don't. What worked for cale may not work for you (and vice versa).

calewjohnson · 07-16-2017, 10:41 PM

Quote:

Originally Posted by ATCguy

Just a thought... we all have different model rigs with different floor plans. You've got an Island light, many others don't. What worked for cale may not work for you (and vice versa).

Sure, but one can also ask for ideas and do their due diligence before cutting into their own rig. I have also gone as far as putting flashlights in the ducts and going down a vent or two with a camera and looking to see the duct integrity. What we pass along here are lessons learned that hopefully others can use. It is by no means the "bible."

Big thing across the various models is tape, tape, tape the vents and air boxes. I had air leaking out of my ceiling lights located near vents. Tape remedied that. If I ever get the roof replaced, I may have them rear the plywood off and install real ducting...

Cale

calewjohnson · 07-16-2017, 10:52 PM

Quote:

Originally Posted by CSCLARK

Ditto on 1 size over lag bolts. Still curious Cale how you cut the extra vent in the living! Did you just mark in between the front and back vent and stay in the middle of that duct chase, then cut right next to the island light drop down? Or did you somehow remove the light fixture island?

Here is my extra vent and you can see the air return that has been enlarged.

I had to put it on the couch side of the trailer, as the stove side has that thing attached to the ceiling.

This gives me five vents in the main living area.

Cale

CSCLARK · 07-17-2017, 05:08 PM

Quote:

Originally Posted by calewjohnson

Here is my extra vent and you can see the air return that has been enlarged.

I had to put it on the couch side of the trailer, as the stove side has that thing attached to the ceiling.

This gives me five vents in the main living area.

Cale

My thoughts too right in front of the couch outside that thing, right. Thanks Cale perfect pic for me to gauge my mod too.

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sparky1266 · 07-19-2017, 03:26 AM

Quote:

Originally Posted by joebedford

He's got a 3970. Doesn't that have that ceiling thingy that prevents direct access to the LR A/C? (like my 3950)

Joebedford you are correct. There is no ceiling access unless you took a jigsaw and made one. We have ceiling access in the bedroom air conditioner but not in the main area.

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