AC air flow problem SOLVED

Same here

Guess we will have to look to some more modifications too. We already had the "tent" which helped immensly (Thanks Tim) however when it was 97 here this weekend the best it could do in our 3055 sitting in the shade was 77 and the unit ran all day until approximately 8:00 pm.

Me too!

I have been reading all of these wonderful ideas over the AC issue and I finally gave it a go. I started with the main plenum in the unit itself. Took off the plastic grille held inplace with (6) screws just like Jim said. I first started with trying to soften the corners were the screw that clamps the unit from inside-out is in-line with the squirrel cage fan. Also created transitional areas in all corners leading to the (2) main plenums of the coach. I have not done the "tent" thingy yet. I have gone to the end of the run vents in the ceiling and created a conical form so that the air hits the form and deflects out the vent instead of the air going past the vent and then down.

One big thing that I did was to pull off the rotating vent and then the round ring that is screwed to the ceiling in the bathroom and basically taped off the entire round ring area that would be in the ceiling. I no longer have a freezer for a bathroom and it feels just fine even in this 90+ degree weather that we are having.

I will try the "tent vent" soon but wanted to take "baby steps" along the way to see how much changer there is for the little things I've done so far. And I have to say I feel a difference so far, hopefully better as I progress through these mods.

Later

Congrats on your success thus far Mark.

Wonder how difficult it is to cut in more vents by one's self? If it is a do-it-yourselfer, maybe I'd try to order the vents from HL and cut them in this season.

Too bad I don't know anyone that owns their own HVAC business, while there are other air-flow testers used, this one looks pretty neat. Measures flow and temperature. Love to have/borrow one for flow and temp readings before and after mods.

For a clear explanation of RV air conditioners and heat gain ,
check this link ,, look for poster 'Garth"
http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/17960844.cfm

I called Heartland today on another subject and asked about adding outlets to the duct system and was told that they feel there are enough vents installed and that they do not recommend adding any. The tech svc rep did say he had heard about the diverter success and that they were looking into that, but I was surprised by his first comment. Personally, I see no downside to doing it, if it works, it works.

Jim, the Velocicheck appears to be a neat tool, but at $525 it is beyond my budget. I would think it would be beyond any dealership budget also. It would make it easy to evaluate mods though.

Clark,

Found several much less expensive units by Extech. See them here at a retailer. For $100 - may be worth having...

Jim

The two cheaper units are more like it, probably accurate enough for this intended use. I did notice the $90 unit had a 2pack of impellers as an option, the other did not. I wonder why it would be needed? I think I could use the instrument here in the mountains when I'm away from my weather station.

The Kestrel line seems to be very popular--lots of sites online carry them. The 2000 as low as $80, 2500 and 3000 are more. They measure quite a few factors.

Just MHO don't waste any time with added vents, witches brew or any Voo Doo. Timks "vent in the tent" is the real cure. After parking the rig today I plugged in the shore power and turned on the air. Went in a little later. So cool you could make a meat locker out of it. The amount of air coming from the LR vents went from a wanna be breeze to a cat 4 hurricane!

Unoriginal Fix

Howdy, living in the Southern Calif desert, my fix was much less imaginative. After 3 weeks of 100+ temps I pulled the front vent out and slapped a 13.5 BTU Dometic in the hole put some open/ close vents in the duct system and cranked her up. Just like Nome in January now!!

Uncle Rog
I like your fix, there is nothing wrong with more power! Only stop then the 50amp break trips, then add a second cord and keep on truckin.

We need more power Scotty.

"Great Stuff"

With the temperature in lower Michigan hovering in the high 90's, I decided to work on the air conditioner and possibly install the tent defectors. I also wanted to play and read temperatures with my new Laser Heat Gun thinking it must be good for other things then checking tires and axale bearings. Some of the readings I took are as follows:
I. Before working on AC-
A. Outside temp at noon 95 deg.
B. when turned air on a themostrat 96, ceiling 100, windows 105
c. At 4:00 PM 100 out, 85 inside @ therm. Evap. temp 75, & AC
vents 78 deg.
II. Next day after AC updates
A. Outside @ noon 98 deg.
B. Inside at therm. 87
C. At 4:00, 100 out & 78 inside, no shut downs
D. Evap temp 68. & vents 72
I still have not installed tent deflectors and might not. Upon inspection of unit, I found there where many open gaps in the framing, around duckwork plumum, and that the Sticky tape to seal between the air return and out put had gaps big enouh to put your finger thru. This was allowing cold conditioned air to be sucked and recirulated back into the return air, not allowing air to be pushed into the duct work.
Fix, I tried carefully to readjust the tape, but was affraid I would tear it and gave up. Then I fastened the tape that was in proper position, to surrounding sheet metal with self taping sheet metal screws. Then I installed 2x4 blocking and shim shingles in the duck work to keep ducts from deforming. I then covered the floor with a paint trap and proceded in spray Great Stuff expanding foam (I have worked with this Great Stuff or years and it can cause a real mess and expand too much ) into a gaps and holes in framing, around ductwork, and filled and sealed cold air side of tape separating air return. Their are two types of spray foam, mininal and regular expanding, use the mininal type. The next day after the foam was set and fully expanded, I trimed everything up, removed spacers, wire tied wires neaty, and installed covers with a new type filter from Home Depot.
The heat gun laser sensor can be shined right up into the vents, return air, evaporator coil, etc. and really gives the full story how verything is working. The gun told me just what I suspected with the Bighorn, windows are gaining alot of heat along with the ceiling.

Another Vote for TIMK for President

I made the Tent in a Vent mod this week plus installed diverters into the registers to deflect the air into the room. Airflow improved by 75% easy. This is still Texas and its still hot, but it is getting cooler. Thanks TIMK

Texan: Did you notice much change when you did the individual vents? I have the "tent in the vent" and it did wonders. Just wonder if doing the others would make much difference. I have read that leaving duct work past the vents is part of the designed in deal so you get equal flow to the others.

ChopperBill said:

Texan: Did you notice much change when you did the individual vents? I have the "tent in the vent" and it did wonders. Just wonder if doing the others would make much difference. I have read that leaving duct work past the vents is part of the designed in deal so you get equal flow to the others.

Click to expand...

I have read the same thing. But my ductwork ends just past the last register. So I decide to put deflectors in several registers. It is an elbow shaped piece of sheet metal the directs the air down into the vent.

Tony

timK, even with my 2nd unit I put in the diverter just so It doesn't sound like a freight train in the rig........good job

Looks like the tent invention is catching on. We had our unit in for some work a couple of weeks ago and the factory suggested that fix for our unit.

Roger

Bowtorc, You said the "factory" suggested that fix for your a/c on your unit. Did they offer to do it for you or suggested you repair it yourself?
Jim

OK - Once again, can someone explain perhaps with pictures this modification. All of these post and still no one has provided details for the rest of use.