AC Upgrade Project

[Will Garner]

I am about to embark on an upgrade from R-420 (high cost replacement for R-12) to R134A. I currently have leak(s) in the system, and since the coach is an April 1991 conversion (#60121), I thought a place to start would be changing out the hoses. I would appreciate any comments guidance available from any source on just how to do this and have the project be successful when done.

I know the project will involve some cabinet disassembly in the galley and at least removal of the bed support in the bedroom in order to get at the condenser units. I have a commercial HVAC person ready to vacuum test the system, repair any of my failed joints, and then charge the system. They already changed over the Dash A/C to R134A. That was quite the project with two Cruisaires in the way of hose connections.

I know someone had a post previously about their compressor being the source of the refrigerant leakage. If they could provide the link to that post it might be a good place to start looking for leaks. I know I will also need to change out other items in the conversion to R134A.

Thanks in advance for any assistance available from our CC knowledge base.

[truk4u]

Will,

My cruisairs are R-22, didn't know they did R-12 with your vintage. I also didn't know you could change the cruisairs to 134a, interesting.

There's all kinds of horror stories about R-12 hose compatibility and 134a, that's why I stayed with R-12 on the dash air. Prevost told me there are flexible hoses mid way on the bus connecting the copper coming from rear to front and fuel tanks have to be removed, etc. Cost, $9000.00. Hector just did a complete hose change on his dash air and I think he stayed with R-12.

[dreamchasers]

Will,

I replaced all of my Prevost air AC hoses. The original hoses were "leakers". Mine leaked the worst in the rear of the coach, I guess the engine heat attributed to the hose decay. All of the hose leaks were in the fittings. I purchased barrier hoses as replacement hose and reused the original reusable fittings. The dash air system improved considerably with the hose replacement and leak check. If you search the forum you will see several posts by Roadrunner and myself concerning AC maintenance.

I also replaced the CC OTC air compressor. Mine was a "bad leaker". The key is to set up a good leak checking process. I purchased a nitrogen bottle and a nitrogen regulator. With this equipment and an AC refrigeration manifold, I was able to find all my leaks. I used a static pressure of 250 psi and a soapy solution to find my leaks. I used seven days as a "no leak" certification. Roadrunner used a product called "Big Blu" for looking for leaks. I have no experience with the product, but he claimed good results.

If you search the forum you will find pictures posted by Roadrunner and dreamchasers that relate to AC system repair.

Concerning R-12 replacement. I chose to stay with R-12. I purchased a 30 pound cylinder from Ebay and used it during the repair. I still have 15 plus pounds left to use as needed. The mineral oil used with R12 is stated not to be compatible with the polyester oil used by R134a refrigerant. My research indicated that I would need to flush the entire system to assure no mineral oil remained. I chose the easy path of remaining the R-12. I did use barrier hoses in the Prevost air hose replacement, just in case I decide to change later on.

Hector

[Will Garner]

Tom,

I am not changing the refrigerant in the Cruisaires. I am dealing with the CC OTR unit for the Galley and Bedroom. The Cruisaires are still running just fine after three years from their being repaired. Yes, they have that high dollar R-420 refrigerant in them. I'm keeping fingers crossed they continue to hold.

Merry Christmas and Happy New Year to you and Nancy.

[Jon Wehrenberg]

Cruise Airs typically have R-22. Actually if the system you are repairing now has 12 in it, there is no downside to remaining with 12 especially if you can restore the system to leak free status. R-12 is about 15% more efficient than 134.

[truk4u]

Sorry Will, I didn't see anything about your OTR, so I was going a different direction!:confused:

Like Jon said, if you can stay with R-12, I'm still finding it reasonable. I had just bought a 2nd 30 lb sealed can for 200.00 before leaving for OKC. I carry gauges and R-12 with me just in case.

Jimmy C has some R-12 that may still available.

[dreamchasers]

Will,

Checkout the link below for more information on how I dealt with rebuilding my CC OTR air. I did not replace my hoses on the OTR system, they seemed OK. My compressor was the main source of leaks. Don't forget to check the operability of the electric fans on the CC OTR condenser.

It took some dedicated work, but the results were worth it.

http://forum.prevostownersgroup.com/showthread.php?t=3171&highlight=compressor

Hector

[Will Garner]

Hector,

Do you recall where you sourced your new compressor and clutch? I am having some difficulty trying to find a local source via the internet. Your clutch and compressor sure look a lot like mine. The only data I can get off the clutch is: #508631 DC-12V, Diesel Kiwi Co, LTD; the compressor has only numbers - 488-22078 and below that number is 509640-1200.

Thanks for finding the old post and sending the link. I'm printing it out so I have a hard copy. I may be calling you after the holidays.

Will

[charlesebrownjr]

Hey Will, My 99 CC has a Valeo VC 31 compressor I purchased from CC a year and a half ago. It is made by Valeo Co. They have a website you might try to find the compressor there or find one of their outlet sources.

http://www.valeocompressors.com/

[truk4u]

Will,

The TM-31 that Hector bought from Carrier may be available at FleetPride. Here's the Carrier link:

http://www.transportaircon.carrier.com/details/0,2806,CLI1_DIV8_ETI271,00.html

You can get compressor mineral oil at Napa if you go that route. I would be reluctant to change over to 134a without all new barrier hoses. I would do like Hector did, put the nitrogen to it and fix the leaks and go back with R-12. If you need help finding R-12, let me know.

[Will Garner]

Hector/Tom,

Thanks for the info and suggestions. At this time there is no referigerant at all in the Galley/bedroom system. As best I can tell, since the PO struck through the R-12 label and put R-420 on it, the system last had that refrigerant instead of R-12. On the Dash A/C, Prevost advised Gregory Poole they would not work on an old unit without upgrading away from R-12 going to R-134A. That was the primary reason for my changing the Dash A/C to R-134A. My thought now is to keep all OTR A/C units working with the same refrigerant. The R-420 was most recently $400 a bottle. The R-134A was most recently $100 a bottle. The dash a/c is now leak free and does a good job of cooling the front of the bus. If I can get the galley and bedroom working the same then we should be in good shape for some years ahead.

Hope everyone had a great Christmas today.