AC not cooling well - Montana Owners Club

napria · 06-23-2014, 06:54 AM

We're back from a week long trip to the Florida panhandle. Lows were in the mid 70's and highs in mid to upper 90's each day. We were in a site shaded by trees and I had the night shades closed all day. Also had the AC set to 74*

That big window in the back still warmed the back bedroom up and the front lounge was not as hot but still very warm. The inside temps stayed between 78* (nights) and 84* (days). Is this normal?

I'm thinking of getting jumbo spring open car windshield sun shades and putting them between the Monty's shades and the window.

DarMar · 06-23-2014, 07:29 AM

WE bought the sunshade vinyl 90 percent UV fabric from Fabric land up here in Canada and cut it to match the glass of the back window. We used the sew on Velcro, 1 inch wide, on the fabric and sewed a strip across the top and about 10 6 inch strips at various places around the edge of the rest. We then used the stick on other half of the Velcro in black color to place on the window glass in the corresponding places. This fabric is wonderful stuff as it severely reduces the heat/light and view coming in yet you can still have a wonderful view looking out. When we move we just peel it off and roll it up. We love this mod!!!

cdaniels · 06-23-2014, 11:26 AM

If you only have 1 air it's not going to do it when temps are in the 90's. We tried it 1year then ordered the 2nd low profile penguin air. Worth every penny spent. Keeping the sun out helps but won't do the trick on a RV your size in those kinds of temps. Haven't had a problem since. Good luck.

nosticks · 06-23-2014, 11:48 AM

Time to get a second a/c.

**DQDick** · 06-23-2014, 03:19 PM

We haven't got above the low 90's yet this summer, but with the humidity, it's quite common for both AC's to be running at the same time during the heat of the day and we have two 15,000's, sunshades on all three rear windows (big back one and both slides), awnings on our slide windows on both sides, slide toppers and four large solar panels on the roof. We stay cool, but we had to spend some money to get that way.

napria · 06-23-2014, 03:32 PM

We do have the second AC (13,500 BTU). We weren't running it all the time though because it was loud in the kitchen/front lounge when it was on. Made it unpleasant when eating and the kids, who were sleeping on the couches up front, said it made it hard to sleep.

I think we need to plan Florida trips for the Spring and Fall from now on.

I'm also going to look into that sunshade fabric.

dieselguy · 06-23-2014, 05:53 PM

On a hot day with the rig you have ... you'll just have to adjust to a bit of noise and run them both or be a tad warm. One A/C just isn't going to keep it cool. As for the rear window ... I installed this retractable sun shade. An easy install and you don't have to attach it or remove it each time you setup somewhere ... you just pull it down like a venetian blind. http://www.carefreeofcolorado.com/ca...t&productid=57

woodtic · 06-23-2014, 07:20 PM

You may also want to look at the A/C ducting to improve the efficancy. Make sure your inlet ducts have not colapsed and filters are clean. You can pop the grills off the outlet vents and make sure they are not obstructed. My duct inserts only had about 1/2 inch of clearance from the top of the duct. I pulled them out and cut down the inserts. now I have about 1 1/2 inches of clearance, level with the bottom of the ductwork, and much better airflow. I also installed 4 extra vents (total of 8) in the main area, and one extra (2 total) in the bedroom. Soon I'll be adding 2 more vents in the bedroom, for a total of 4. The modifications really helped the A/C's preformance.

dieselguy · 06-24-2014, 02:46 AM

woodtic ... assuming a design tech took a stab at balancing airflow with exit area (number and size of vents) in reference to your A/C system ... wouldn't doubling the existing number of vents end up with more of a whisper than a blow out the vents? Maybe in RV's it doesn't matter like it would in a stick house. I do agreee about trimming the stack sticking up into the main duct on each vent ... it noticably improved the breeze in my fiver.

richfaa · 06-24-2014, 03:06 AM

One A/C does not do it in these larger Montana's. These are Rv's and not at all insulated like a S&B.
With temps in the mid 90's one A/C will struggle to keep the camper at 75/78 if it gets there at all. We have both of ours set at 80 degrees and usually the rear one will go on before the front one. These things are not very efficient when it comes to heating and cooling..that's Rv'ing.

woodtic · 06-24-2014, 05:25 AM

Quote:

quote:Originally posted by dieselguy

woodtic ... assuming a design tech took a stab at balancing airflow with exit area (number and size of vents) in reference to your A/C system ... wouldn't doubling the existing number of vents end up with more of a whisper than a blow out the vents? Maybe in RV's it doesn't matter like it would in a stick house. I do agreee about trimming the stack sticking up into the main duct on each vent ... it noticably improved the breeze in my fiver.

It did reduce air velosity through each vent but not by much. I'd say 15% less, if that. Something I left out of my earlier post is that I changed all the vents from 5" with fixed vanes to 4" with adjustable vanes. There is still significant flow even with only one A/C unit running. Still the volume of cool air admitted to the space has been increased significantly. In the bedroom now, I can open the Quick Cool vent on the unit (bedroom unit off) and improve cooling in that space if needed. From previous experiences (DW), it would just be simpler to install two additional vents and leave the big one closed all the time.

Something else I've noticed is that there is a higher discharge pressure on the port side of each unit. It has to do with the design of the A/C unit itself, not the external ducting. That is something I can use to my advantage.

Got the Idea from OZZ. Has been a great modification. Speaking of OZZ, where has he been hiding?

gjetzen · 06-24-2014, 06:56 AM

napria, spring and fall aren't much better! The in-laws live in Bradenton and the DW flies down in May and the temps are usually in the mid to upper 80's. We take the Monty down in mid September and stay through the end of October again temps in the mid to upper 80's, except for this past fall when temps in October were in the middle 90's. We only have 1 A/C unit and find that when it is in the 90's outside, it will knock off about 15 degrees during the heat of the day, and the A/C unit runs constantly until the sun goes down, shaded site or not it doesn't matter. So if it's in the mid 90's outside we can get the inside down to about 80-82 degrees. I think that's pretty good. What I have found to be helpful is to run the ceiling fan on medium and a small oscillating in the fan on low in the front bedroom and the quick cool vent open. This I believe helps to circulate the air. We keep our thermostat set at 77 degrees.

swanny · 06-24-2014, 02:29 PM

here's what we do. first block the sun exposed windows with the silver insulation stuff ( like for a car windshield ) cut it to fit. next remove your floor heat registers and tape the off so no cold air can escape through the duct work and out the furness, close off the vents under the steps if you have them. get ceiling vent pillows to block heat. We also bought a external sun screen for the picture window, works like a window shade. this will help works for me.

kevin

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