Reply
 
Thread Tools Search this Thread Display Modes
 
Old 07-27-2016, 03:25 PM   #1
3 Rivet Member
 
2015 25' FB Flying Cloud
Sandy , Utah
Join Date: May 2015
Posts: 107
What should I expect from AC Unit?

I have a one year old 25FB with a single Dometic 15,000 BTU unit. In full sun I will get about 78 degrees interior on a 90 degree day with 40% Humidity and all awnings out. Is this good or bad?
__________________

__________________
rocco52 is offline   Reply With Quote
Old 07-27-2016, 04:22 PM   #2
Rivet Master
 
AnnArborBob's Avatar
 
2014 27' FB Eddie Bauer
Chelsea , Michigan
Join Date: May 2010
Posts: 1,680
Images: 12
I've been told that at most you will see a 20 degree drop in temperature between inside and out. Full sun, asphalt or concrete vs. grass, humidity and the like will affect your performance. A 12 degree drop is disappointing but may be about right. Also, a "hot" Airstream will have a lot of built up heat in the aluminum and wood structural elements that could take overnight to cool down. The AC in your Airstream is not like a car where you can expect to go from deadly heat to comfortable inside a half hour or so.
__________________

__________________
Bob Martel
WBCCI# 5766
AnnArborBob is offline   Reply With Quote
Old 07-27-2016, 04:31 PM   #3
Moderator
 
HiHoAgRV's Avatar

 
1991 34' Excella
1963 26' Overlander
Central , Mississippi
Join Date: Nov 2006
Posts: 5,111
Images: 29
Blog Entries: 49
That seems marginal to me. 90 and 40% isn't that bad in my area. I've never measured mine but we regularly camp in hotter temps and we like it COLD inside. You should see 15+ degrees difference between the intake temp and the cool outlet directly at the AC unit.
__________________
Hi Ho Silver RV! Vernon, Sarah, Mac the Border Collie -
A honkin' long 34' named AlumaTherapy http://www.airforums.com/forums/f205...num-54749.html
and a 26' '63 Overlander, Dolly http://www.airforums.com/forums/f109...ome-71609.html
HiHoAgRV is offline   Reply With Quote
Old 07-27-2016, 05:56 PM   #4
Rivet Master
 
HowieE's Avatar

 
1991 34' Excella
Princeton , New Jersey
Join Date: Aug 2003
Posts: 6,529
Images: 12
The way to test an AC unit is to measure the return air temperature just before the inlet and the delivered air temperature at the out flow grill. The best an AC can do is 20 degrees, more likely 15 to 18 degrees. If you are getting that the unit is working as best it can.

People just believe AC is AC and forget the factors of unit size and load on the unit. When you first get into a hot car you will note that the delivered air temperature is quite high. As the AC cools the car the delivered air temperature appears to get cooler. That is only because it has brought the in let air temperature down at a faster rate than the sun can heat the ca
__________________
WBCCI 12156 AIR 3144 WACHUNG TAC NJ6
2004 Excursion 4x4
1991 34 ft. Excella +220,000 miles, new laminated flooring, new upholstery, new 3200 lbs axles

HowieE is offline   Reply With Quote
Old 07-27-2016, 06:59 PM   #5
Rivet Master
Commercial Member
 
lewster's Avatar
 
Currently Looking...
Naples, FL , Hood River, OR
Join Date: Dec 2005
Posts: 7,127
What should I expect from AC Unit?

The accepted measure on an A/C unit's performance is known in the industry as 'delta-T' which is defined as the temperature differential between the cooled air being exhausted from the evaporator when directly compared to the air temp measured AT THE RETURN AIR GRILL.

Note that this has nothing to do with ambient temperatures measured outside the trailer.

The delta-T for a properly operating unit should be measured after the compressor has been operating for 15 minutes, and should show a differential between 18-22 degrees F.

If your unit fails to reach a delta-T of at least 18 degrees F. , then you have operational issues which could range from a bad start capacitor that will not allow the compressor to initiate and run to a refrigerant leak in your system.

Both issues are easily diagnosed by a competent and experienced RV tech.
__________________
Lew Farber...ABYC Certified Master Marine Electrician...RVIA Certified Master Tech ...AM Solar Authorized Installation Center...AIRSTREAM Solar & Electrical Specialist
lewster is offline   Reply With Quote
Old 07-27-2016, 08:43 PM   #6
Rivet Master
 
Al and Missy's Avatar

 
2002 30' Classic S/O
Melbourne Beach , Florida
Join Date: Nov 2013
Posts: 1,788
Quote:
Originally Posted by rocco52 View Post
I have a one year old 25FB with a single Dometic 15,000 BTU unit. In full sun I will get about 78 degrees interior on a 90 degree day with 40% Humidity and all awnings out. Is this good or bad?
My 2001 Safari 25 had an 11,000 BTU AC and only the curbside awning. In my driveway in east central Florida with full sun on the roof and road side and afternoon temperatures in the low 90s, it kept the temperature and humidity comfortable after 30 minutes or so of run time. It would get down to 74 or 75 as I recall. It had the "mouse fur" walls and padded vinyl ceilings. I think that provides some additional insulation over the bare aluminum skins.

Al
__________________

"You cannot reason someone out of a position they have not been reasoned into"

Al, K5TAN and Missy, N4RGO
2002 Classic 30 Slideout
S/OS #004
2013 Dodge 2500 Laramie 4x4 Megacab Cummins
2001 Safari 25 RB Twin (Gone, but not forgotten)
WBCCI 1322, TAC FL-39, AIR 82265

Al and Missy is offline   Reply With Quote
Old 07-28-2016, 11:54 AM   #7
4 Rivet Member
 
1973 31' Sovereign
Middletown , California
Join Date: Oct 2015
Posts: 355
That seems a bit weak unless you waited until the trailer was heat soaked before turning on the AC. It makes a difference if you start the AC early in the day so it can try to keep up with the suns heating of the skin. A friend used to leave his AC on all night while bundled up in winter clothes so that it would be cool enough in the afternoon in his old 30 footer. He was at an RV park with no trees but electricity was included. You just can't beat parking in the shade in the summer! You can check to make sure that your AC has unrestricted airflow on both hot and cold sides, and check the delta T as suggested.
__________________
ijustlee is offline   Reply With Quote
Old 07-28-2016, 12:08 PM   #8
Rivet Master
 
KJRitchie's Avatar

 
2008 25' Classic
Nixa , Missouri
Join Date: Nov 2012
Posts: 3,887
My 2008 Classic 25fb has a Dometic 13.5k. This past weekend it was 96F and humid at the local lake. Trailer sat in front of the house with A/C before we left and it was 96F in there. When I got set up at the lake I turned on the A/C. Our A/C thermostat is located in the front bedroom and was set to 72F. Our site was in full sun and as the sun went down it blasted onto the rear (living area) windows. I deployed the rear and street awnings but not the main as it didn't provide any shade from the setting hot sun. Put the Fantastic Fans on for 10 minutes to vent hot air then closed them. I have a thermometer across from the fridge and it cooled down to the mid 80s. The next day with all awnings deployed the A/C was able to maintain upper 70s until late afternoon and it bumped up to the low 80s. The front bedroom cools down faster than the rear dinette area as cool air is channeled in the hallway to the bedroom. Through the day the A/C compressor cycled on/off until late afternoon. We turn Auto off to keep the A/C fan running when the compressor cycles off. I may try lowering the bedroom thermostat to a lower temperature to see if the rear cools down better but in this particular site the rear was getting all the afternoon sun. We have the mouse fur and vinyl ceilings too. Water was pouring out fast from the drain tube by the street wheel well, it was so humid. I feel the A/C is working the best it can.

Kelvin
__________________
2008 Classic 25fb "Silver Mistress"
2015 Ram 2500 6.7L Cummins. Crew Cab, 4x4, Silver
2010 Tundra 5.7L, Double Cab, 2wd, White
KJRitchie is offline   Reply With Quote
Old 07-28-2016, 02:35 PM   #9
Tampatomgirl
 
1990 34' Excella
Zephyrhills , Florida
Join Date: Apr 2016
Posts: 90
I wonder why noone has mentioned roof seal, window tinting or uva rated screens, curtains, etc. There's only so much a rooftop A/C unit can do to cool a hot metal box in full sun with 90+ temps. You may have to help it along. I'm in full sun in Tampa, Fl. Thise are my solutions for sweat free afternoons. Good luck!
__________________
Tampatomgirl is offline   Reply With Quote
Old 07-28-2016, 04:43 PM   #10
3 Rivet Member
 
2015 30' International
FREDERICK , Maryland
Join Date: Jan 2014
Posts: 196
What you describe is why we sold our 25' Flying Cloud. When camping in NM in the summer, it would be 95-100+ and we could get the front living area after a long while down into a comfortable temperature, we could never get the rear bedroom cool. We ended up with a 30' with 2 A/C's and even with temperatures 100+ this summer in AZ and NM we could get the whole trailer quite chilly, even to the point where we had to turn off one of the A/C's as it got too cold. Awnings all the way around definitely help when there is no shade. The ducted air definitely helps with distribution and noise reduction.
__________________
Doc Foster is offline   Reply With Quote
Old 07-28-2016, 05:55 PM   #11
Rivet Master

 
Vintage Kin Owner
Nowhere , Somewhere
Join Date: Jul 2005
Posts: 5,860
If one end of the trailer is cooler than the other, I find the use of a small fan to push the air around is prudent.
__________________
1984 Avion 30p 9.1 meter. 2006 Dodge 3500 cummins srw short bed crew cab.
avionstream is offline   Reply With Quote
Old 07-28-2016, 06:18 PM   #12
Rivet Master
 
KJRitchie's Avatar

 
2008 25' Classic
Nixa , Missouri
Join Date: Nov 2012
Posts: 3,887
OP has a 2015 and I would think the A/C would distribute better for even temperatures. If I could maintain 78 in the rear living area with full sun I'd be more than happy. Mines is the old style air distribution box in the middle of the trailer.

Kelvin
__________________
2008 Classic 25fb "Silver Mistress"
2015 Ram 2500 6.7L Cummins. Crew Cab, 4x4, Silver
2010 Tundra 5.7L, Double Cab, 2wd, White
KJRitchie is offline   Reply With Quote
Old 07-28-2016, 06:30 PM   #13
Rivet Master
 
Howard L.'s Avatar

 
2012 30' Flying Cloud
San Antonio , Texas
Join Date: Jul 2012
Posts: 577
Reading this post, we are sitting in full sun outside Santa Fe NM in our 2012 30 FC with two ACs (13.5 and 15). With the full sun and daytime highs mid 90s every camper with less than the max ACs his rig will carry is having trouble keeping cool. We talked to a couple with a 2011 30 FC, one 15 K AC unit, that couldn't get their unit cooled down during the mid day even using a strong fan blowing from the read bedroom. They left a week early the next day for cooler Colorado. My two ACs will keep us at the mid 70s selected if I start the units running early in the morning but by mid day they are pretty much running full time. Like stated above, awnings, shade of any kind makes tremendous difference. To get an idea of the heat you are fighting, feel both the outside and inside skin that is sitting in direct sunlight at mid afternoon.
__________________
Howard L. is offline   Reply With Quote
Old 07-28-2016, 07:37 PM   #14
3 Rivet Member
 
2015 25' FB Flying Cloud
Sandy , Utah
Join Date: May 2015
Posts: 107
Thanks everyone for your input! I will run the test on my next outing and see if it is within specs. Even at 78 degrees it was nice to have a place to cool off after hikes. Being new at this I was not sure what to expect.
__________________

__________________
rocco52 is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
What should I expect with my 12V system? M and M Generators & Solar Power 15 10-25-2015 01:19 PM
What cooling should I expect from a new fridge? DHart Refrigerators 30 08-13-2015 03:02 AM
What should I expect to pay for new brakes and tires Mary Burris Wheels, Hubs & Bearings 2 05-22-2012 06:59 PM
Should I expect some rattling from my Interstate? rv40 Sprinter and B-van Forum 12 03-18-2010 08:35 PM
what to expect? Chas Airstream Trailer Forums 20 01-18-2003 02:19 PM


Virginia Campgrounds

Reviews provided by



Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 06:20 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.

Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.