Over-the-road-air problems

[Larry]

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.

[wayne]

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

[dreamchasers]

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

[johnklopp]

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.

[BoaterAl]

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.

[rahangman]

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

[ToyMan]

Larry,

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

[dreamchasers]

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

[Steve D]

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

[Gil_J]

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.

[Joe Camper]

If anyone is interested I bought a R12 vacuum and recovery machine for removing and adding R12 and no longer have that bus.

If someone wants it let me know.

I too had my OTR AC repaired and stayed with R12. It was inop for who knows how long when I got it and once sealed up needed no Freon afterward right through the sale.

For the record 134A is harder to contain than R12 the molecules r much smaller in 134a hence the 134a lines require O-rings where the r12 lines never had.