So I have been wrestling with this 34 year old Winnie that has been turning black with mildew out behind the barn...so to speak. Getting down to the short strokes and want to bring back the OTR AC. You know it is a R12 system cause the last time I used her they hadn't invented 134. Well I have been of on a scavenger hunt for all my components and a replacement for the venerable York compressor. Talked to more than a few "experts" in the trade. I have acquired a really large condenser and a dryer and little more than info beyond that. I finally called a shop across town and asked about getting all new houses cause 134 goes thru F12 rated stuff. The nice man asked why I was converting and I told him I had no problem with the system at all except that it leaked down over the winter. Every winter! Wasn't a problem when R12 was cheap and I didn't understand about the ozone. Now I have concerns. AC guy said he would pressurise my system with a trace of R12 and nitrogen and find the point of leak and maybe we could repair the system instead of going to the expense of ripping it out. He seemed to be on my side...remarkable. I told him I had 4 cans of R12 from days gone by and he estimated I would need 60 to 120 dollars worth more max, if any, and he could provide it. Now isn't that a happy ending? Course it isn't over till the Fat Lady sings and I get frosty.
Did you know you can have a R12 system repaired in this day and age? I will have it pumped down before I junk the old girl next year.
John
Hi John,
You don't have to use R-12 and you don't have to retrofit to R134A either. There is a direct drop-in replacement gas for R12 that uses the same oil,
TX valves, and hoses. It's called R-409A. A blended gas with very close chactoristics as R-12. The most notable differences are in charging the system.
For an R-12 to R-409A retrofit, with a system that uses a TXV , you should use approximately 85 - 90 % of the charge weight for R-409A that was
originally used with R-12. When running at steady state conditions, you can expect to see suction pressures very similar to what the system ran at with
R-12. The discharge pressure will typically be 15 - 25 psi higher than it was with R-12.
To determine if the system is charged properly, you also want to check your superheat and subcooling. The best way to determine what the values of
superheat and subcooling should be for your system with R-12 is to contact the OEM. The values of superheat and subcooling that you should expect to see
with R-409A will be similar to those used for R-12. Once the system charge and other settings have been optimized, and the system is running at steady
state conditions, there may or may not be trace amounts of bubbles in the sight glass.
Good Luck
Nick-
Nick,
That is great news.
Thanks,
John
With the cost and inconvienance of repairs plus the age of the compnents and you are getting rid of Winnie next year. Might you be better off running the genset and useing the roof air?
Jim
Nick- do you have to completely evacuate the system to switch to the R409A, or can it be used as a topper? Can R12 and R409A be mixed? And can we as mere mortals buy R409A over the counter like we can with R134A? Sort of important to be able to "top" off the system when on the road. Even with the cost of switching to R134A, it maybe less in the long run since most auto parts stores sell the 1lb cans of R134A like they used to with R12. Good Luck, TomC
Tom,
I keep my cars a good long while. 10 years min and I don't buy new but I have two and sometimes three cars on the road at any given point in time. I have only had one car serviced for low freon and the Winnie. AC seems to be a good reliable system...in general. If I were to switch to "any" freon I would expect to never revisit that issue in the two years she has to live. Expense is the driving factor for me but it goes without saying that it "must" operate. People I have talked to, Nick included, have confirmed that 134 is not as effective as R12. Maybe efficient is a more proper word. Some that converted to 134 found that their AC system was no longer adequate. I guess it is if the system is designed for the application but I understand that the condenser and evap and compressor are much larger than an equal tonnage R12 system. My R12 system was really powerful so I thought I might be able to take the performance hit and still be adequate. Then I got into the differences in the the two systems from the hardware system requirements and I lost confidence. Seems that all the rubber hoses need to be replaced in a system as old as mine so I opted to rebuild/replace the old system. I had been told by HVAC savvy people more than a few times over the years that I "couldn't" use 409 and they were good guys all and I can only surmise that by "you" they meant me personally because it takes a HVAC licence to squirt 409 around and not that the systems are not compatible. If I can get the same performance from 409 as I did from R12 I will definitely go that way.
Thank you all for your interest and comments....especially you Nick,
John headed for cool.
Quote from: TomC on October 24, 2008, 09:50:39 AM
Nick- do you have to completely evacuate the system to switch to the R409A, or can it be used as a topper? Can R12 and R409A be mixed? And can we as mere mortals buy R409A over the counter like we can with R134A? Sort of important to be able to "top" off the system when on the road. Even with the cost of switching to R134A, it maybe less in the long run since most auto parts stores sell the 1lb cans of R134A like they used to with R12. Good Luck, TomC
Hi Tom,
Yes, you would need to evacuate the system of R-12. But, only because the presure chactoristics will change your readings
if you are trying to get it right. R-409A is a little more expensive then 134 but still waaay cheaper then R12. i have not seen
it in small cans like 134 but most Refrigeration guy's like myself have the 30lb bottels.
Good Luck
Nick-
If anyone is interested
I have a 30 lb bottle of R12 - It now weights 11 lbs
not sure what the container weights - but-
It's $50 - I'm near Daytona Florida - just a few minutes from I-95
Pete ...386..672..0571...
Come and get it !!!!
sorry - don't think I'll be at Arcadia this year
JFYI In British Columbia the only replacement for R 12 is R134a. It is against the law the charge a system with any ozone depleting substance. Saying that you can buy off the shelf "Artic chill" I think that is what is called, which has htdocarbons, propane? We can not use R12 at all either ertro fit or drain and leave empty
Lloyd
RTS,
Stop that! It is against fed reg to sell or buy R12 unless you are licensed as a HVAC and have the R12 ticket punched. Beside that, it sells for much more than $50 a "pound" so you are giving away a valuable commodity.
I hope you get email from off line and maybe drop Nick a PM and get his advice. I am sure he wouldn't risk his licence, name or a fine but he most probably will have some private advice.
HTH,
John the worrier
Hey John
I no longer have a need for the r12
Just wanted to help any local Bus Nut out
So - why don't you just KMRA !! (KISS MY ROYAL A$$ !!)
Pete RTS/daytona
FWIW you can sell R 12 all day and night without having any license. You just can't BUY it without a license. The requirement is that the seller must verify that the buyer is certified and licensed to own and handle the stuff, or not sell it to him. That's all...
Boogie,
I haven't read any HVAC regs ever. I was told "buy or sell" by two different auto AC shop owners and I wasn't selling or trying to buy anything, just BSing and visiting. Two of them in a row doesn't prove anything though. If you are sure I am with you and thanks.
Daytona Pete,
That was a trifle strong. :o Not to mention uncalled for. :-[ The apparent "spirit" of your post will get you banished in short order. :'( I hope that doesn't happen to you but be assured it has happend to others. :-X All of us try to be constructive and helpful and not take anything personal. :-[ If you ever see me or any other heading twords breaking the law in any way I sure hope you would sound off.
If you read a little further back you would have seen that I have a few cans of R12 in my possession. Barely enuf for one auto system charge but it should be of value to any HVAC guy.....Like Nick(HVAC contractor) and he is in your neighborhood. I intended to send him my stash out of simple gratitude for the TONS of help he has been to others and me personally on this board. What goes around comes around...if you know what I mean and I am having some doubts here. ??? Although, everybody that is trying to keep you out of poop isn't necessarily your friend and everybody that is trying to get you into the poop isn't necessarily your enemy, it usually follows. 8)
About your request to KMRA....I thought the R stood for "Redneck". ??? I guess it all depends on where you come from and how you were raised. ;D I just doubt you are Royalty, is all. ;) As to your request: you will have to chalk off a spot cause from here it appears nearly impossible to discern where that part of your anatomy begins or ends. :D ;) ;D Now see how much more palatable that sort of talk can be if you include all those cute little symbols and some kind words. I have seen a lot on this board but you are not only unique in your posting but a "natural" as well. I hope this clears the air and we can become mutually supportive friends. All in fun now and know that this is a flat medium and subject to missinterpretation and my post is friendly and well intentioned. :-*
John
Uh..Oh.. :o :o
Somebody let Rudolf the Redneck Reindeer off the harness again....
::) ::) ::) ::) ::) ::)
i changed my van and my accord to 134, i simply pulled a vacume and changed the fittings added oil and charged them up, 15 yrs ago, no problems with either. i know they say you need to change hoses and all that, i didnt do it. works for me
Frank Allen 4106
Frank,
Me too. Mine were still doing fine years later. All were factory air. The dilemma is that all the info I get lately forcasts DOOM and GLOOM. And, they have spooky pictures to back it up. One guy said he had the fix...he used a couple cans of 134 to "flush" the system and then filled with 134 and new oil. The thing that gives me heartburn is that this system is from 1973. I think Nick had the best solution as using 409 is compatible with R12 in all ways. I need to have the leak found and corrected anyway so I will let the shop charge the system with 409.
Thank you for your comment and info,
John
I have a bunch of older vehicles. When one with R12 leaks out I simply recharge with R134, have had no problems at all. There is even an oil that works with either so I use that if I lose any.
I changed my freon manifold hoses so the old fittings can be used with R134 freon cans.
Although the pressures are slightly different I can tell no difference in cooling.
Gus,
Yours is the best report so far. I never heard of the oil you mention but I am sure a lot of other people are taking note. I would not hesitate to load her up with 134 cause I don't think I have much to lose. The fly in the ointment is that the system leaks down in a few months and needs recharged at least a couple times a year. Back then I had no concern for the ozone but I am getting smarter. I will have a shop locate and correct the leak and then have that same shop recharge with R409. 134 has a definite disadvantage when compared to R12. If you switch and 134 is OK then your R12 system had excess capacity. That's fine but mine is in the front of a 30 foot Winnie and I could never have too much. You have broken new ground here and I applaud your success.
Thanks for sharing that,
John
John
Ahoy, Nick,
I see that R-134a is a single gas, and that R409 (A,B) is a mix. Can you enlighten us on how the R409 behaves when there is a leak? Does selective distillation occur, so that you must evacuate and refill to regain the properties? (I have an A/C certificate, but that aspect has 'faded').
Thanks /s/ Bob
John, i did pull a good vacume on both systems and added the 134 oil to the charge since they say its not compatable with the r-12 oil, i dought there could have been much if any in the system, our local mech adds 134 to R-12 systems all the time and says he has never had a problem. just thought id add this info
Frank allen 4106
Quote from: Bob Belter on October 26, 2008, 09:59:58 PM
Ahoy, Nick,
I see that R-134a is a single gas, and that R409 (A,B) is a mix. Can you enlighten us on how the R409 behaves when there is a leak? Does selective distillation occur, so that you must evacuate and refill to regain the properties? (I have an A/C certificate, but that aspect has 'faded').
Thanks /s/ Bob
Hi Bob,
Yes! All blended gasses leak different properties at different rates.
Good Luck
Nick-
John,
I am a vehicle collector nut so I have about six older vehicles with AC, only one of which originally had R134 (a '94 Dodge one ton). The others are all '70s and '80s models. About half have very slow leaks (over the winter) and one usually requires one can of R134 in the spring. I don't consider this a significant leak in the overall scheme of things, especially considering the cost of auto AC services these days.
I've used the canned freon stop leak with some success. I've also found that most of my leaks have been loose or faulty valve cores. I don't understand how they become loose as little as they are used but they do.
As long as the system has any pressure there is no need for evacuating. Air and moisture cannot enter the system against any pressure.
The dual purpose oil came from my friendly local Bumper to Bumper auto parts store.
The only place I've found R134 at a reasonable price is at Sam's Club by the case but other box stores probably have equal prices.
Well I have found R-22 to be an awesome refrigerant! We have customers asking for HEAT in the summer time! We just started using it this summer, but I see a very long lasting relationship with it & us! FWIW
;D BK ;D
Gus,
That was where I was back when I was using the coach. I charged her up every spring. Now that I have to convert to 134 I felt I had to "fix" the system and upgrade the components. If this 409 freon works out I will be home free and not have to bother with anything except the leak. Love it when plan comes together. ::) Thanks for sharing your experience and I think you have a solid approach.
BK,
I take it you converted your R12 systems to R22? How did you do that? Aren't they phasing out R22 in the near future? Hope not..for you.
Thanks,
John
Both of the MCI's we bought this summer were already converted from R12 to R22 when we bought them. (We sold 1 of them today!) But let me tell you it is rare in the charter business to heat people complain about being COLD! Most of the time you can keep them comfortable, but in the HOT summer time it is hard to FREEZE them out like these 2 buses do!
I am sold on using R22! Even if I have to build a stock pile of it! FWIW! ;D BK ;D