Reply
 
Thread Tools Search this Thread Display Modes
 
Old 07-06-2012, 11:19 AM   #1
1 Rivet Member
 
McDonalds's Avatar
 
1971 25' Tradewind
Bowdoinham , Maine
Join Date: Jan 2011
Posts: 19
AC Doin' Okay??

Okay, it's 100 degrees outside and 80 degrees inside. It's blowing about 63 degrees. Is my air conditioner okay or should I replace it?
__________________

__________________
McDonalds is offline   Reply With Quote
Old 07-06-2012, 11:33 AM   #2
Rivet Master
 
StreamRollin's Avatar
 
1999 25' Safari
Denver , Colorado
Join Date: Jun 2011
Posts: 2,781
Images: 15
As it goes I think you are getting about all the cooling you are going to get. Iv'e heard that 20 degrees lower is about right. I used to have a 21.5 ft Mitchell 5th wheel which I had put a new AC unit on, dont remember what brand it was (I think there are only 2 on the market) but we could get that 5th wheel down well below 70 from 100 degrees if we wanted.
Jim
__________________

__________________
Jim D.
AIR # 56543 TAC# CO-10
StreamRollin is offline   Reply With Quote
Old 07-06-2012, 11:50 AM   #3
Rivet Master
 
Gene's Avatar
 
2008 25' Safari FB SE
Grand Junction , Colorado
Join Date: Sep 2007
Posts: 10,840
Once you check on the price of RV A/C, you may decide yours works fine. Some people report they get temps about 20˚ below outside temps. Ours usually does much better than that—at least 30, maybe 35˚.

Things you can do: park under a tree, make it rain, put out awning on sunny side, get Reflectix and put it on roof penetrations and sunny windows inside, clean filters on A/C. You may be need the refrigerant recharged too. Is this the original A/C? If it is 41 years old, it deserves a medal for still working so well. What is the BTU rating for it?—it may be undersized for the trailer.

Gene
__________________
Gene is offline   Reply With Quote
Old 07-06-2012, 11:52 AM   #4
Rivet Master
Commercial Member
 
lewster's Avatar
 
Vintage Kin Owner
Naples, FL , Hood River, OR
Join Date: Dec 2005
Posts: 7,279
Quote:
Originally Posted by McDonalds View Post
Okay, it's 100 degrees outside and 80 degrees inside. It's blowing about 63 degrees. Is my air conditioner okay or should I replace it?
Manufacturer specification for roof mounted air conditioners is 18*-22*F below inside ambient temperature, this is called 'delta T'. Let your unit run for about 15 minutes. Measure the temp. of the air at the cold air outlet, them measure it again at the return air intake. The temp. differential should fall in the range stated above.
__________________
Lew Farber...ABYC Certified Master Marine Electrician...RVIA Certified Master Tech ...AM Solar Authorized Installation Center...AIRSTREAM Solar & Electrical Specialist...Micro Air 'Easy Start' Sales and Installations
lewster is offline   Reply With Quote
Old 07-06-2012, 12:24 PM   #5
Rivet Master
 
Gene's Avatar
 
2008 25' Safari FB SE
Grand Junction , Colorado
Join Date: Sep 2007
Posts: 10,840
Lew, if I read your post correctly, the 20˚ differential is not between outside and inside temperatures, but between what goes in the A/C and what comes out. Correct?

We start out at 60˚ on the thermostat and that seems to cool a bit faster, and when the temp gets down to around 70˚, we turn up the thermostat.

Gene
__________________
Gene is offline   Reply With Quote
Old 07-06-2012, 12:41 PM   #6
Rivet Master
 
Currently Looking...
Nowhere , Somewhere
Join Date: Jul 2005
Posts: 6,417
Blog Entries: 2
As an experiment my AS was 104 inside. I set the AC on78 on high fan and in an hour it eas 84 inside. This was partial shade. Outside temp was 95. Everything was closed up. I used a tower fan to move air to the warmer side of the trailer. There is usually as much as 4 degrees dif front to back. Exp. done, I have no idea if it would have gotten any cooler, but we keep our house st 82 so I was happy. Remember this camping! Jim
__________________
avionstream is offline   Reply With Quote
Old 07-06-2012, 01:23 PM   #7
Moderator
 
DKB_SATX's Avatar

 
2017 26' Flying Cloud
1976 Argosy 28
Alamo Heights , Texas
Join Date: Aug 2006
Posts: 6,401
Images: 1
Blog Entries: 7
Quote:
Originally Posted by CrawfordGene View Post
Lew, if I read your post correctly, the 20˚ differential is not between outside and inside temperatures, but between what goes in the A/C and what comes out. Correct?

We start out at 60˚ on the thermostat and that seems to cool a bit faster, and when the temp gets down to around 70˚, we turn up the thermostat.

Gene
Unless something is wrong with your thermostat, this is just a placebo effect. Unlike automotive AC that sometimes mixes in warmer air when you're at a "medium" setting (on a fully-manual system) or when the air temperature approaches the set point, the roof AC (and usually the one in your house) just has "cooling at max rate" and "compressor off" options. So, while setting a temperature well below what you really want makes you feel like you've sent a message to the machine, the machine just runs at its usual rate until a) it reaches the set point or b) you change the set point to something attainable.

The reason I said "usually" regarding residential AC, there are some newer systems with multiple levels of performance. Some of them are for the multi-head split systems, so the compressor isn't wasting as much energy when just running some of the inside units, but I've seen references to regular AC systems with variable-speed compressor units.
__________________
David

Zero Gravitas 2017 Flying Cloud 26U | Il Progetto 1976 Argosy 28 Center Bath | WBCCI# 15566

He has all of the virtues I dislike and none of the vices I admire. Sir Winston Churchill
DKB_SATX is offline   Reply With Quote
Old 07-06-2012, 01:30 PM   #8
Rivet Master
 
2005 19' Safari
GLENDALE , AZ
Join Date: Aug 2004
Posts: 2,441
A couple of tips:

* Use auto shade screens to block light and lower heat gain through windows.

* Use shade screens over vents and FantasticFans, too.

* Start air conditioner early in the morning before heat starts to build to pre-cool inside surfaces. (Inside air cools quickly; but later in the day, your air conditioner will also be trying to cool down the walls and all contents, too.)

* Gene's suggestion regarding shade will help the most. Very few trees in Arizona, except in the mountains (where it is already cool); but one can tell a significant difference in air conditioner performance, if you can find shade (even partial shade) for your Airstream.

* Don't shower mid-day or hang wet towels inside. Extra humidity decreases same-temperature comfort factor. 80-85 degrees at 5% humidity in Arizona is pleasant, if one is not standing in the sun; compared to 80-85 degrees at 80% in the southeastern US, which is very muggy and uncomfortable (at least for Arizonans).
__________________
Phoenix is offline   Reply With Quote
Old 07-06-2012, 02:07 PM   #9
Rivet Master
 
1981 31' Excella II
New Market , Alabama
Join Date: Sep 2011
Posts: 5,648
When it gets over 100 degrees outside my 4 ton heat pump for the house will just keep the house at about 80 degrees. I should have a 3 ton heat pump on that house according to specs.

The same goes for my 31 ft trailer. It will keep it at about 80 inside when it is 100 outside. There is only so much it can do. The recomendations above about reducing heat load are good ones.

Perry
__________________
perryg114 is offline   Reply With Quote
Old 07-06-2012, 02:08 PM   #10
Rivet Master
 
Gene's Avatar
 
2008 25' Safari FB SE
Grand Junction , Colorado
Join Date: Sep 2007
Posts: 10,840
Quote:
Originally Posted by DKB_SATX View Post
Unless something is wrong with your thermostat, this is just a placebo effect. Unlike automotive AC that sometimes mixes in warmer air when you're at a "medium" setting (on a fully-manual system) or when the air temperature approaches the set point, the roof AC (and usually the one in your house) just has "cooling at max rate" and "compressor off" options.
I've wondered about that because it doesn't seem to make sense as you say. But if the compressor cycles more frequently as the temp is dropping when you set the temp at 70˚ than when you set it at 60˚, then it would work. It seems to work and hooray for placebos if that is the answer. I could sit in the trailer listening for cycling and do comparisons, but I'm not going to. Maybe I should set the thermostat at 40˚ and see if I can make the entire trailer a refrigerator.

Gene
__________________
Gene is offline   Reply With Quote
Old 07-06-2012, 02:15 PM   #11
Rivet Master
 
vswingfield's Avatar
 
1983 34' Excella
1967 24' Tradewind
Little Rock , Arkansas
Join Date: Nov 2006
Posts: 3,773
Images: 32
Quote:
Originally Posted by perryg114 View Post
When it gets over 100 degrees outside my 4 ton heat pump for the house will just keep the house at about 80 degrees. I should have a 3 ton heat pump on that house according to specs.


Perry
OK, here's an issue I've never seen on the forums before. When I read the thread, the paragraph above says:

Quote:
When it gets over 100 degrees outside my 4 ton heat pump for the house will just keep the house at about 80 degrees. I should have a 3 ton heat pump on that house.
The last three words "according to specs." don't appear. It doesn't make sense. When I included the quote in my reply, they appeared and the paragraph made sense.

Using Firefox on Win7. Strange forum behavior.

Back to the original topic, I'm very pleased when I get the inside of my Excella down to 80 when it's 100 outside and in the sun.
__________________
Vaughan
vswingfield is offline   Reply With Quote
Old 07-06-2012, 02:18 PM   #12
Rivet Master
 
Diesel1's Avatar
 
1967 24' Tradewind
Wickenburg , Arizona
Join Date: Aug 2008
Posts: 546
Quote:
Originally Posted by McDonalds View Post
Okay, it's 100 degrees outside and 80 degrees inside. It's blowing about 63 degrees. Is my air conditioner okay or should I replace it?
Your A/C sounds like its working as intended. Enjoy it!
__________________
Fortune cookie say....."Prudence keeps life safe, but does not often make it happy."
Diesel1 is offline   Reply With Quote
Old 07-06-2012, 02:20 PM   #13
Moderator
 
DKB_SATX's Avatar

 
2017 26' Flying Cloud
1976 Argosy 28
Alamo Heights , Texas
Join Date: Aug 2006
Posts: 6,401
Images: 1
Blog Entries: 7
Gene: The modern ones may cycle the compressor before getting down to the set temperature, but I'm guessing that unless it detects something wrong (over- or under-temperature on some sensor, etc) it'll run the compressor full tilt until it gets down to the set point. I'm certain my old one works that way.
__________________
David

Zero Gravitas 2017 Flying Cloud 26U | Il Progetto 1976 Argosy 28 Center Bath | WBCCI# 15566

He has all of the virtues I dislike and none of the vices I admire. Sir Winston Churchill
DKB_SATX is offline   Reply With Quote
Old 07-06-2012, 02:51 PM   #14
Rivet Master
 
1981 31' Excella II
New Market , Alabama
Join Date: Sep 2011
Posts: 5,648
I edited the post so you probably read the post before I added the last little bit of information. I think faster than I type.

Perry

Quote:
Originally Posted by vswingfield View Post
OK, here's an issue I've never seen on the forums before. When I read the thread, the paragraph above says:

The last three words "according to specs." don't appear. It doesn't make sense. When I included the quote in my reply, they appeared and the paragraph made sense.

Using Firefox on Win7. Strange forum behavior.

Back to the original topic, I'm very pleased when I get the inside of my Excella down to 80 when it's 100 outside and in the sun.
__________________

__________________
perryg114 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
Tips for first timers Janet H Member Introductions 507 10-31-2017 07:05 AM
Lots of People Are Doin' It! Fly at Night Winter Living 1 12-06-2011 10:39 AM
Water filter ccetex Classic Motorhomes 5 10-18-2011 09:46 AM


Virginia Campgrounds

Reviews provided by




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 04:58 AM.


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.