A/C cooling on a hot day

[guru1961]

Good post Richfaa! As the owners of a 2014 Big Sky Montana with "unsurpassed hot weather comfort" according to the brochure that came with this hunk of...well fiberglass/metal. Our unit will maintain 80 degrees when it gets 90...and 85 when it gets 95...and 88 when it gets 100. Similiar conditions as you described...no shade...ours is pointed west so most of the sun is beating down on top during the heat of the day. Had both AC's units tested (working fine according to techs) and took temp readings at vents - 58 air at LR vent and 60 air at BR vent on 93 degree outside day. We have also installed insulation wrap on all windows & door & skylight. Very little difference. Keystone has took the position - unit is not defective. Working as designed. I am considering adding a 3rd 15k btu AC to the kitchen area since my selling dealer nor Keystone will even consider testing the unit for comfort! We got what we got - which is...well I think all know what I am thinking. I have considered trading unit for SOB - but we would be so upside down it wouldn't be worth it. We will just suffer with this inferior product until we can get something better. You can bet your sweet biffy it won't be anything from Thor or K.stone. We were pleased with our 2006 Montana 3400RL and are amazed at the quality dropoff since then. Night and day--oh yea AC's work great after dark!

[bncinwv]

I must be of the lucky sort, we were at Hilton Head (105 heat index - temp 94) for a week and Topsail, FL (heat index - 107 - temp 94) for two weeks and never had a problem keeping the unit at 76 to 78 degrees inside. Leaving the rig into the oppressive heat would fog glasses, cause instant sweat attacks, feel like an oven, and cause you to quickly catch your breath. We do run the AC's at high fan and do crank them up first thing in the morning. Only open shades on the side without direct sunlight) and leave front door open with vinyl covering the screens. When the overnight temps dropped into the mid-80's, we could run one ac and maintain the 76-78 temp inside. Not sure what we are doing different. We have black ac covers, black slide toppers, lots of black and gray paint, but we do have double pane windows. One other thing is when we are at the rig, we keep one basement door open since I need ready access to the dorm fridge and the cold drinks inside. I personally cannot complain about the ability to keep the rig comfortable during high temps and high humidity levels. Color me blessed, I suppose??
Bingo

[richfaa]

guru1961 You would do no better with a SOB. We observed that the outside temps had little to do with it but the temps of the sidewalls and the inside walls did.

[guru1961]

J-Co Pinnacle does advertise 8 hours @ 100 degree tested and gives 72 as high temp. Now I would venture that putting it in a 100 degree room for 8 hours is not the same as baking in sunlight but I believe it would be better than what I am getting out of this RV. Also the OPN Range 3X has way better numbers on their testing. I find it hard to believe that someone can say with a straight face that 86-88 is acceptable for "unsurpassed hot weather comfort". Well I didn't get to see their face---which in the long run is probably best! Hopefully the 3rd AC dumping another 15k into the middle will help close the gap on the heat. I also got the great help from K-Stone to run the fantastic vent fan while the other 2 AC's are on to pull the hot air out of the RV. Yea that works great...where does it get the air to pull? Temps went up like 5 degrees in 15 minutes. Wonderful idea!

[richfaa]

guru1961.The temps you measures at the A/C vents 58 and 60 are excellent your A/C's are operating normally. In our case the sun beating on the roof and sidewalls was causing extremely high temps on the sidewalls and much of that was being transmitted to the inside walls of the Montana. I mentioned that the inside wall of our bathroom was at 92 degrees and it was hot in the bathroom. Check you vents some of ours were obstructed. When we blocked the roof vents and windows we got the temps down to the mid 70's on a very hot day. One can only put so much insulation is any RV .

[davidaf]

Outside temp is 98 inside is 78. We are in direct sun w/o shade. Most of the blinds are closed and both ACs are running. We have a large solar screen in the picture window for later in the day when the tail is in full direct sunlight. The sunshade guy should be here any minute to install covers on some of our windows. I expect we'll hit 81 in the living room today w/o the sunshades as the sun moves over us. I can live with 81. If it gets better with the shades I'll be that much happier.

[guru1961]

Yes richfaa I can relate to the heat transfer to the inside walls as some are hot to the touch in places. I have had the ducts checked by service center 3 weeks ago and removed all kinds of debris from the return vents. They also stated the return vents were collapsed or almost closed. They opened them up...but I will use the 1.5" PVC pipe trick explained in another post here to open up for sure and good! They also repaired like 4 - 2" holes in the main duct they could reach that were just letting cold air escape the ducts. I did receive an interesting phone call this afternoon from a Keystone service rep who stated they were sending a rep to my location here in OK to check out the unit....well that will be something different and much appreciated!! I might forget about SOB! I will followup with a post about the results and path forward after the tech pays me a visit.

[richfaa]

guru. If you are getting the temps you posted at the A/C vents I doubt that the ducts are collapsed.

[Virginia Young]

guru1961 - We have the exact same unit you have and are in central FL. We are on a lot with no shade and have stayed very comfortable for the past week. I did remove all the vents and trimmed them down so they didn't stick up into the ductwork very far. That did seem to help a little with the airflow. I have covered the floor vents with those magnetic covers from Home Depot and installed the silver bubble insulation behind the step vents. I keep the fans set on High and had the thermostat set to 72 for the first few days, but hubby said I was turning him into a popsicle, so I turned it up to 75 on both units during the day. We like it cooler at night and turn the bedroom down to 73 when we go to bed. I guess I should put the pillow in the kitchen vent - forgot about that . . . TV is on most of the day. Shades are all down in the bedroom, but up in the living area - except for the ones the sun is shining directly into. Those I pull down until the sun moves. Awnings are out and we do have a Sun shade on the big front awning. Hope this helps you a little.

[guru1961]

Thanks Gina. I will show the Keystone tech your response. All I've heard from service and salesman is this unit is doing all it can. I agree the AC's are putting out the proper cold air but the insulation is not doing its job. This was advertised as a 4 seasons living RV-it's not in the summer in Ok. Hopefully they will figure it out.

[richfaa]

guru.. four seasons Rv means you can live in them all four seasons. That's it. We are able to cut that down to one season since we summer north and winter in Florida but still have cooling problems. We have never had a keeping warm problems as we rarely have had to use the furnace. The fireplace does the job.

[Firsterin]

I saw a post with a jury rig fix to help AC, something to do with 1.5" PVC pipe but now I can't find that post. Will the original poster or some other kind soul please direct me to that particular post. Thanks!

[rohrmann]

http://www.montanaowners.com/forums/...ad.php?t=60791

[richfaa]

More interesting information. Since we are grounded for the summer I have got way to much time on my hands. Installed my new TST tire monitor system. It measures tire temps, my replaced system did not..The Montana is sitting in the driveway one side in the direct sun the other in shade. Tire PSI set at 110 PSI. Tires in the direct sun 114/115 PSI tire temp 84/85 Degrees.
Tires in the shade PSI 109/110 Tires temp 80/81. The Wheels are not turning and have not been turning. That is just the sun on the tires. Think about the temps on the gel coat on the sun side and why we have problems cooling. After taking all these reading with my trusty IR thermometer I better understand the cooling issues and have the data to back it up.

[guru1961]

Keystone RV tech arrived as planned yesterday at 2pm and tested our RV air system (AC's and ducts). He took temp readings of all areas. He made a couple repairs to duct system up on roof after removing the unit over LR area. He verified all fan blower operations of both units. After all that testing and work, it was 89 in RV when he turned AC's back on. It was 82 inside when he started (95 ambient). 30 minutes later it was 85 and didn't get any cooler until sun begin to set (by that time he was gone). He will report his findings to his supervisor but he feels the unit is...wait for it... NOT maintaining the temperature it should. I will wait for his supervisor's response.

[bncinwv]

What I have learned over the course of dual air conditioners in the three rigs we have owned is simple. If you do not cool the rig immediately in the morning, you will not catch up in any manner during the heat of the day. The AC's keep and kept all our rigs cool as long as I followed this process.
Bingo

[Crow317]

We have a 2014 High Country RL343. The AC in the living area has gone bad! Had unit less than a year. Keystone has agreed to replace it. Waiting on unit to arrive. Going to have thermostat checked out as well. Unit never cycles off even when temp on thermostat is set high! Here s my question in dealing with all this we have discovered the smaller unit is in the larger vented living area. It is a 13500 btu. The drop down unit In the smaller bedroom is a 15000 btu. We have been round and round with keystone. They say unit is designed that way. Bedroom will freeze you out!! Living area HOT!! High ceilings just not enough force to blow cool air! Does anyone else have this configuration with a/c units?

[bigskyjimmy]

Yep we love the high ceiling's but it does make it harder too cool in the living area and the bedroom gets ice cold ,but like Bingo said start the cooling early and also we close the bathroom door and leave the bedroom door open and the ice cold air comes down into the living area since we do that it works great and we stay nice and cool,it was 100 degrees last week and we were all good

[Lkelly3400]

Bigskyjimmy, I have a 2015 3610 RL and have the same AC Configuration. The front blows cold air through the vents throughout the RV. The rear will do a quick cool of the bedroom OR you can close the louvers and it will blow through the same vents as the LV AC. I've had no cooling issues when coming back to a hot rig when I use both AC units blowing through the vents.

[bigskyjimmy]

Thanx for the info ,I did not know if you close the bedroom louvers it will go thru the living room vents I will try that

quote:Originally posted by Lkelly3400

Bigskyjimmy, I have a 2015 3610 RL and have the same AC Configuration. The front blows cold air through the vents throughout the RV. The rear will do a quick cool of the bedroom OR you can close the louvers and it will blow through the same vents as the LV AC. I've had no cooling issues when coming back to a hot rig when I use both AC units blowing through the vents.