Go Back   iRV2 Forums > THE OWNER'S CORNER FORUMS > Alpine Coach Owner's Forum
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Thread Tools Search this Thread Display Modes
Old 02-06-2013, 03:18 PM   #1
Senior Member
1peddler's Avatar
Alpine Owners Club
Join Date: Jan 2006
Location: West Covina, Ca 91791
Posts: 105
Dash Air Problems

When we turn on our dash air, it will cool for 20 to 30 minutes. Then it will blow warm to hot air. If we turn it off for 30 to 45 miniutes and back on it will cool again for another short time. Any thoughts why this is happening?

Dennis And Sally
2005 40FDQS
ACA & SoCal
1peddler is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 02-06-2013, 04:12 PM   #2
Senior Member
Join Date: Aug 2004
Posts: 412
One of the most common causes for the indications described is that the evaporator freezes up and will not let air pass through...to supply cold air. Air being blown in under these conditions is not cooled because heat is not exchanged through the evaporator. This is frequently caused by an improper freon charge in the system (usually too low because the system may have leaked a little refrigerant over time). R134 has a narrow operating range compared to the old R12 and is more difficult to properly charge systems. The reason it cools again down after awhile is that the ice has melted from the evaporator and allows air to pass through once again.

'01 Alpine 36 FDDS
SteveS is offline   Reply With Quote
Old 02-06-2013, 04:43 PM   #3
Senior Member
bluepill's Avatar
Join Date: Jan 2011
Location: Pensacola, FL
Posts: 2,032
Steve's post is a good possibility. Evap. freezing means that the temp. goes below 32 degrees. The optimum temp. at the evap core is a few degrees above freezing. If you test the dash vent outlet temps and find them below 40 degrees, freeze-up is a good possibility.

Another thing that can give your symptoms is a weak clutch on your compressor. As it heats up from use, it stops engaging. If you can visually check the clutch, you can see if that is happening.

Good luck.
2008 Itasca Meridian 37H & 2015 Flagstaff T12RBST
2011 & 2012 Len & Pat's "One lap of America"
27K miles & 41 states in 13 months - Woo Woo
Yellowstone Lake 6-1-2012
bluepill is offline   Reply With Quote
Old 02-06-2013, 05:17 PM   #4
Senior Member
Algoma's Avatar

Join Date: Nov 2007
Location: Charleston, WV
Posts: 2,166
If you haven't got the equipment you need to go to an A/C shop and have them check the high and low pressures in the system. You may have too much or too little Freon in the system.
John and Mary Knight
2015 Ventana 4311, 2015 Cadillac SRX
Algoma is offline   Reply With Quote
Old 02-07-2013, 07:24 PM   #5
Senior Member
Join Date: May 2004
Location: Auburn, CA, Havasu, AZ & Mulege, BCS
Posts: 5,172
On our rigs can also be a vacuum problem where the dash air selector doesn't hold its selection. I have this or a similar problem, when the cooling runs out (heat never does), I can turn the switch off then back to AC and cooling comes right back. Sort of like rebooting a computer.
Not sure how to solve that. Its on my list. Which isn't short.
Baja-tested '08 2-slide 36'
Alpine: The Ultimate DIY'er Project
EngineerMike is offline   Reply With Quote
Old 02-08-2013, 08:48 AM   #6
Family Man's Avatar
Join Date: Nov 2011
Posts: 31
You have a list??? I'm afraid to make a list. The cost of the ink and paper alone would likely break me...
The Family Man
2001 40FD
Family Man is offline   Reply With Quote
Old 02-11-2013, 11:45 AM   #7
Join Date: Mar 2006
Location: Texas
Posts: 50
Solving air conditioning refrigeration problems is like going to the doctor. One or more problem may exist.

The unit may simply be low on freon which can cause part of the evaporator to freeze up and cold air stop. This is the most common problem. The expansion valve is not able to do its job without the proper level of refrigerant. Go to a automotive shop and buy a combo that will allow you to put freon in your system and a gage that will tell you if you are low on freon. The low side connector is on the exterior firewall area and the low side connecter is where refrigerant is added. Add freon until the gage reads you have the correct amount of freon. That may solve your problem. With the amount of refrigeration hoses in motorhomes, a small leak is common. Currently, I add a can of freon about every two years. I doubt I can find a leak this small!

The expansion valve may be defective. When you turn on the dash air, the expansion valve opens to its capacity to as quickly as possible pull out the calories inside your coach. As the inside of your coach cools, the expansion valve restricts the flow of freon resulting in a colder outcome as the liquid refrigerant expands quicker in the evaporator with less freon allowed to flow into it. If the refrigerant level is good, anything outside this function, the expansion valve most likely needs replacing.

Another possible problem is the system may have moisture. If not properly evacuated to remove all moisture after the system is open, moisture can be present in you freon. The moisture if not caught in the dryer, may freeze up at the expansion valve stopping the flow of refrigerant. If you have not had any work done to your dash air system that include unscrewing hoses in history, then moisture may not be your problem.

Someone else touched on a problem with the compressor clutch. The greatest load on a compressor is when it is first turned on. Slipping can be heard and visually seen and sometimes smelled. This condition will get worse with system use. Sparks can ultimately fly from a compressor clutch as it scrubs metal to metal and the compressor will not longer turn.
Good luck in establishing your solution.

2003 Alpine Coach
2009 Jeep Wrangler 4-Dr Rubicon
rbguinn is offline   Reply With Quote


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

» 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 2002-2015 Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 05:24 AM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.