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Author Topic: 4905 air conditioner  (Read 3028 times)
larryh
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« on: June 26, 2006, 08:23:55 AM »

On my bus everything works but needs a charge and can find nobody to service R22 refrigerant. Has anybody converted over to 134A their self.?

Do I have to charge compressor seperate from condenser and do I need two kits to do it?

Any input will be appreciated?

Larry Higuera
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TomC
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« Reply #1 on: June 26, 2006, 08:44:52 AM »

Usually the change over will involve completely evacuating the system, changing the reciever dryer and the oil in the compressor to 134A compatable.  Rinse the system with Nitrogen, and also change the charging ports to the 134A type.  Shouldn't be a problem since R22 is rather corrosive as compared to 134A (R22 requires you use copper tubing compared to 134a that uses regular neoprene type hoses).  Maybe Nick will chime in here.  Good Luck, TomC
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« Reply #2 on: June 26, 2006, 10:24:49 AM »

R-22 is (NOT) interchanglable with R134.
R-22 will out cool any R-134 system that was converted.
Different system pressures with R-22/R-134.The suction and discharge pressures are higher with R-22.
R-22 should be easy to find a few years ago I bought a 30 pound cylinder of R-22 at Sam's.
jlv

 

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« Reply #3 on: June 26, 2006, 01:01:21 PM »

Nothing current on the R-22?  I need some to charge the A/C in my boat.  Nick....Help?Huh??
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« Reply #4 on: June 27, 2006, 06:16:08 AM »


The P8M4905A GMC Coaches( HAVE) R-22 installed from the factory.
If you read the GM P8M4905A maintenance manual it states this as a fact.
jlv
« Last Edit: June 27, 2006, 10:55:25 AM by Nick Badame Refrig. Co. » Logged
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« Reply #5 on: June 27, 2006, 06:43:42 AM »

System capacity aprox. 60 pounds R-22.
jlv
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« Reply #6 on: June 27, 2006, 09:42:26 AM »

Larry,
I'd keep it R-22, for sure. From the prices I've seen by Google-ing for refrigerants, R-134A is almost twice the cost. AFAIK, R-22 has not been phased-out the way R-12 has, so it's still affordable, and superior to R-134A.

The biggest question is whether to keep your coach air system maintained or just pull it all out. From Da Books, it seems the biggest sections of maint. are always the coach A/C systems. And yours was designed to keep 49 passengers chilled in a leaky, multi-window bus... not an insulated, skinned-over coach (if that's what yours is). So the compressor will likely cycle on and off quite a bit in RV service... or freeze you out of the bus. 60# of R-22 will set you back a few hundred $ and chasing down those leaks, winterizing, testing, and keeping all 60# of that precious fluid from leaking out will be an ongoing part of your PM.

Plus, as you know, the coach air can only be used when rolling down the highway and not when parked. And the compressor and condensor compartments are great places to put stuff like batteries and gensets. Some busnuts use the term "free A/C" or "if it ain't broke don't trash it" as justifications for keeping the coach A/C intact... but the former is never the case (those compressors rob some serious HP) and the latter seldom is... like in your case. The only way they don't "get broke" is to "keep fixin' em".

Anyways, I'm not trying to throw rocks or anything, just giving some food for thought. Please keep us posted on your system and its progress.

Brian Brown
4108-216

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Brian Brown
4108-216 w/ V730
Longmont, CO
larryh
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« Reply #7 on: June 27, 2006, 10:17:14 AM »

Brian

No insult taken just your two cents worth and a honest opinion. This bus was a trailways bus originally and has been owned by two church groups and kept CA. Hiway Patrol inspected each yr.
The owner told me they had to have it charged each summer and tuned up but that everything was operational as far as he knew. My decision is to keep it and get to know something else for yearly maintenance. Or to change out now. I'm in the process of stripping it out now and getting ready to convert. My plans are to keep the original windows as much as possible no plans to raise roof etc. I want to keep the Buffalo appearance as much as possible outside . now the inside will be a different story. I am a diesel mechanic of 47+ yrs so maintenance is a piece of cake for me. and I'm more than willing to help others on this group.

Larry Higuera
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« Reply #8 on: June 27, 2006, 10:32:28 AM »

Larry, your knowlege and experience will be a great asset to this board and its users!

I LOVE the Buffs... esp. the stock ones with the humps. Mine was capped front and back before I got it, so I'm stuck with the "Space Ship" look.

Please keep us posted on your progress. And take lots of pics. And as you get to know your coach A/C system and its workings, you'll be a great help to those that choose to keep their systems intact.

Thanks,
Brian
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Brian Brown
4108-216 w/ V730
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DavidInWilmNC
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« Reply #9 on: June 27, 2006, 10:52:59 AM »

  .
« Last Edit: June 27, 2006, 11:28:27 AM by DavidInWilmNC » Logged
Nick Badame Refrig/ACC
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« Reply #10 on: June 27, 2006, 10:59:31 AM »

Guy's

I modified some postings here!  This subject was getting out of hand. When it does, I will delete!!!!

Nick Badame
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« Reply #11 on: June 27, 2006, 11:08:13 AM »

On my bus everything works but needs a charge and can find nobody to service R22 refrigerant. Has anybody converted over to 134A their self.?

Do I have to charge compressor seperate from condenser and do I need two kits to do it?

Any input will be appreciated?

Larry Higuera
Larry, you DID say any input would be appreciated.  Christy (and her husband Larry) own a heating and air business and are generally very helpful.  I don't know much about servicing bus A/C units, and I didn't get the idea that you did either.  Questions like "Do I have to charge compressor seperate from condenser and do I need two kits to do it?" don't really indicate a knowledge of these systems.  Her post was meant to keep from causing problems or hurting yourself, not as an insult.  She indicates this in the last line of her poste "Please do not be offended as this post, as is not intended to denigrate you,   it is merely meant to save you from hurting yourself or your a/c system."

I ask a lot of questions on this and the BNO board.  I sometimes get answers that I don't agree with.  I do try to respond politely to those that bother to post.  When people take time out of their day to try and help me, how can I be anything other than appreciative? 

David

Now this is silly.  It doesn't make a heck of a lot of sense for me to refer to two posts that are no longer available (have been deleted).  Although I understand we want this to be a friendly place, we are all adults and need to learn to get along in a civil fashion without posts being deleted.  I know that Christy didn't mean to sound bad in her post; I wonder if she'll take the time to post again, since hers, that contained a good bit of general info has been kicked to the curb (deleted).    Angry
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Nick Badame Refrig/ACC
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« Reply #12 on: June 27, 2006, 11:21:11 AM »

David,

I'm sorry you feel that way, We certainly don't want anyone to feel uncomfortable here.

But, This board will not put up with any childish mud slinging!

My job is to keep this board clean and tasteful, And Thats What I Will Do!

If something is deleted here, it is first been discussed between Two Moderators before any action is taken.

Reguards
Nick-
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« Reply #13 on: June 27, 2006, 11:40:01 AM »

So, I guess I missed way out on something. . I thought someone was talking about their R-12 bus air system, converting it to R134.  If I sounded stupid or something, I apologize, but I guess I didn't realize that he was talking OTR air.  I sure did my best to be polite, just concerned if they were talking about rooftop a/c units or the OTR air that originally had 12. 

I didn't see any other posts, so I don't know what was said after mine, as I just now checked the site, so I just will assume that I must have insulted someone or said something someone took wrong.  If so, I apologize. 

Believe it or not, we run across quite a few people who think that R-22 and R-12 are the same thing and are interchangeable.  I personally know of someone who insisted that their home and truck used the same freon, going so far as to trying to put R-22 in it and destroying a compressor.  I realize now that being unfamiliar with new busses, I didn't realize that OTR a/c units had R-22 in, and if they did, why someone would choose to go to R134, which is again, why my brain was saying R-12. 

So, if I said something wrong, I apologize, but if someone doesn't mind, could you contact me privately, and let me know what all I said wrong, because I thought I was making it clear I meant no offense, and since I didn't see any of the other posts, I'm assuming I was the one who said something offensive.  I'd prefer not to let it happen again.  Christy Hicks
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« Reply #14 on: June 27, 2006, 12:09:35 PM »

Christy, in my opinion you did not say anything that was, or should have been, taken as offensive. Your post had a lot of good information in it which would be valuable to all the readers of the board. I know I learned something from it. Again, in my opinion, you have nothing to feel bad about or apoligize for. Keep up the great posts!

Richard

So, I guess I missed way out on something. . I thought someone was talking about their R-12 bus air system, converting it to R134.  If I sounded stupid or something, I apologize, but I guess I didn't realize that he was talking OTR air.  I sure did my best to be polite, just concerned if they were talking about rooftop a/c units or the OTR air that originally had 12. 

I didn't see any other posts, so I don't know what was said after mine, as I just now checked the site, so I just will assume that I must have insulted someone or said something someone took wrong.  If so, I apologize. 

Believe it or not, we run across quite a few people who think that R-22 and R-12 are the same thing and are interchangeable.  I personally know of someone who insisted that their home and truck used the same freon, going so far as to trying to put R-22 in it and destroying a compressor.  I realize now that being unfamiliar with new busses, I didn't realize that OTR a/c units had R-22 in, and if they did, why someone would choose to go to R134, which is again, why my brain was saying R-12. 

So, if I said something wrong, I apologize, but if someone doesn't mind, could you contact me privately, and let me know what all I said wrong, because I thought I was making it clear I meant no offense, and since I didn't see any of the other posts, I'm assuming I was the one who said something offensive.  I'd prefer not to let it happen again.  Christy Hicks
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larryh
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« Reply #15 on: June 27, 2006, 12:22:56 PM »

Well even if somebody is out of line and giving wrong information you don't want anybody to correct that information then I guess I was out of line if you want me to remove myself from the board I will certainly do so just let me know but whenever i'm personally attyacked I will respond in fact if you don't like honesty and openess then I made a mistake coming here'

Larry Higuera
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« Reply #16 on: June 27, 2006, 12:38:28 PM »

Larry, let me be the one to respond to you.  First of all, you have a nice name  Wink, which makes me partial to you.   Obviously, as you saw, I missed some of what went on, as I had to go to work and fight a nightmare of a day, which makes this little issue a very minor one.   Wink

I must have been half asleep this morning, when I made the assumption that you were talking about an R-12 system,  Huh  and it would have been better for me to stay out of the discussion and wait and see exactly what you were talking about.  I jumped to a conclusion and if I offended you by insinuating that you didn't know what you were doing, I apologize directly to you.  I simply wanted to make sure that someone didn't get hurt or get themselves into trouble. 

Perhaps things have gotten blown way out of proportion, I don't know, but I bet if we agree to be friends, everyone will be happy and we can all go on our way in peace.  Cheesy So, here's the olive branch, grab ahold and let's just jump off the cliff together.  (After the day I've had at work, I either need to jump off a cliff or throw someone else off one.  Wink)  We've got a lot of good discussions (arguments) ahead of us and neither of us wants to miss out on them, do we.  Be talking to you soon, Christy Hicks

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« Reply #17 on: June 28, 2006, 04:49:28 AM »

So, anyway, back to the subject at hand. . .changing an R-22 OTR system to R-134a. Cheesy

In order to do so, you would, at the very least, need to change the compressor and the metering device, since 22 and 134/12 run different pressures.  You probably wouldn't have to change any coils, but you surely would have to run a good long vacuumn on the system to make sure you evacuated any air and residual freon from the system.

Personally, I think it would be a mistake to change it over, as 22 is much more plentiful and less expensive than 134a.  About the only reason I could see someone doing so,  Huh would be because it's harder to get certified for R-22 refrigerants than for R12/134a freons, so you may have difficulty purchasing R-22 without a card.  The test for the automotive style freons is a simple, open book test and is inexpensive, whereas the test for full certification usually involves a seminar and proctored test, but it still isn't a difficult test IMO. 

If you are thinking about keeping the 22, my advice would be to contact a refrigeration contractor in your area, as they will have experience with practically all types of freon, and might be less frightened of dealing with an OTR system using 22.  Wink As for attempting to convert it, well, that will be very expensive and really will not solve the problem of leaks, unless the leak is from the compressor, which would be changed.  Again, I don't know a lot about the OTR systems, so this is just my opinion based on my limited a/c knowledge of freons and the differences between different ones.   Grin Christy Hicks
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« Reply #18 on: June 28, 2006, 04:57:03 AM »

Larry,
  The first question that comes to mind is "Where did the R-22 go?" You said the system is fine except it needs re-charged. Before recharging, I would try to determine where the R-22 leaked out and correct the leak. Depending on how bad the leak is, you could end up spending a lot of diesel fuel money keeping the AC working.  Hopefully someone that knows about AC systems can give you some pointers on finding the leak.  Jack
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