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Thread: Over-the-road-air problems

  1. #1
    Join Date
    Feb 2012
    Posts
    2

    Default Over-the-road-air problems

    After many fine years, the over the road air system on our H3-40 decided to give up. According to Prevost, it is leaking in more than one location. This would not be a huge issue EXCEPT that our coach was one of the last made using R-12 refridgerant. The R-12 is very expensive with no guarantees it won't leak out somewhere else if we fix the leaks. The cost to convert the system to R-13/14a refridgerant is enormous as all the lines from end to end and most of the AC equipment needs to be replaced. If anyone else out there has had to face this issue, I would love to know what they decided to do.

  2. #2
    Join Date
    Nov 2009
    Location
    Montell, Texas....40 miles north of Uvalde which is 80 miles west of San Antonio
    Posts
    146

    Default

    Larry.....I think it is Hector who has bought R12 on eBay....might look there.

  3. #3
    Join Date
    Oct 2010
    Posts
    190

    Default

    Larry,

    I too had issue with Prevost concerning upgrading (What they called it) my R12 system to R134a. You should be aware that your system component sizes were designed for R12 and will operate differently with R134a. How much differently is for one with more knowledge of AC systems to answer. I wanted my systems to operate at maximum efficiency, so I stayed with R12.

    It was ridicules what the quoted price was from Prevost. I saw they did not want to do the work, so they quoted a very high price. Remember, your system will not operate in the same manner as before a refrigerant change.

    My fix was to repair my existing systems to a leak free status. It was easy. I pressure checked the bus air system, CC Bus Air, and found my leaks were on the compressor. It apparently had gotten hot at a time in its life. The reason was one of the condenser fans was not working. Replaced both condenser fans, replaced the leaking compressor, pressure checked the system with nitrogen at 250 PSI and leak free for 3 days. Recharged and all has worked for the least three years.

    On my dash air, I did replace several hoses in the rear of the coach that was exposed to engine heat. Again, checked for leaks, now all OK.

    AC work is not magical. It does require some work, but is doable. Also, POG member John Kloop is an AC expert and has helped me on an occasion through phone calls.

    Concerning purchasing R12. I have purchased R12 from Ebay. The last 30 pound cylinder was $430. A 30 pound cylinder will last a very long time.

    The key is to establish a leak free AC system before charging.

    I searched for the post where I documented the work I did on my AC, but not success.

    Regards,
    Hector

  4. #4
    Join Date
    Sep 2010
    Location
    Mt Baldy, CA. and Nashville, TN.
    Posts
    111

    Default

    I agree with Hectors recommendations. Buy a 30 pound cylinder of R12 to keep the system at full performance. Soap bubble check all the accessible fittings and add refrigerant. Even if a few small leaks remain, you will have enough refrigerant for the next 10 years. If you want to go a step further purchase an electronic refrigerant leak tester and use it to sniff for leaks.

  5. #5
    Join Date
    Feb 2010
    Location
    Kansas City, MO
    Posts
    497

    Default

    I agree with the experts above.

    Question, has anyone given you a idea after testing where the problem is ?

    Repair your current system with R-12. Test, test, the system before reinserting the R-12. As the experts above went to a step above to routine testing prior to recharge with R-12 most often pulling a vacumn gives a pretty good heads' up if leaks are gone.

    Another way to look at this problem is you have no assurance converting to 134 A will be trouble free.

  6. #6
    Join Date
    Mar 2009
    Location
    Harrison
    Posts
    623

    Default

    My CC over the road 'Dash" air is beginning to work. It has been changed over to R134a and if Hector is correct (which I am sure he is) it is working but not as well as expected, but then, there is still work to do. Thanks for all the above info

  7. #7
    Join Date
    Feb 2010
    Location
    Polk City
    Posts
    102

    Default

    Larry,

    Where are you located? I have 2 30lb cylinders of R-12.
    Ron & Suzie Hampton
    2001 Marathon H3-45
    Ford Edge towinf 4 down

  8. #8
    Join Date
    Oct 2010
    Posts
    190

    Default

    Quote Originally Posted by ToyMan View Post
    Larry,

    Where are you located? I have 2 30lb cylinders of R-12.
    Toyman,

    I live in Livingston, Texas and am always interested in keeping a stock of R12. If interested in selling a cylinder, please PM me.

    thanks,
    Hector

  9. #9
    Join Date
    Dec 2013
    Location
    North Bend
    Posts
    7

    Default

    Hi Larry,
    This is my very first post as I have a very similar coach/problem. The compressor (otr) froze up on my H3-40. I was wondering if you had any ideas on how to locate either a rebuild kit or new/re-build compressor? Thanks in advance. Steve

  10. #10
    Join Date
    May 2012
    Location
    Beverly Hills
    Posts
    4,652

    Default

    Larry,

    If your OTR air is Prevost OTR air then the compressor is over sized for motorhome applications. If the compressor requires replacement you might want to call one of the companies that specialize in bus air. It's likely they will recommend a smaller compressor. This will also be the ideal time to transition to R-134a. Many of us CC owners are satisfied with our CC OTR cooling capability which uses Prevost dash air and a similarly sized OTR air system supporting the main living area and bedroom. This just reinforces the fact the Prevost OTR air is oversized. Prevost's system is designed for a full window coach with 50+ people.

    You also have the option of running the generator on hot days to run your AC powered airs. This is what the plastic coach guys do.


    Gil and Durlene
    2003 H-3 Hoffman Conversion

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