R12 to R134 Conversion Tip

[afgunn]

Might want to make a sticky of this. I experienced this when I converted my system.

I do not know how many of you have converted or had converted your older R12 AC system to R134 but you should also replace the "Cycle Switch" located on the Receiver/Dryer. This can be done with the system fully charged because the mount has a schrader valve. Make sure the new one is for R134 freon. R134 has a lower low side pressure than R12. If you leave the original R12 Cycle Switch installed it will cause the compressor to "short cycle" which will put a lot of additional unnecessary wear on the compressor clutches and the system will not cool nearly as well as it could.

[arveetek]

Good info. If you don't replace or adjust the switch, the system won't work correctly.

Some of the switches are adjustable, like the one on my '81. When I converted it to 134, I was able to adjust the pressure at which the switch kicked the compressor out. If you unplug the electrical connection, there should be a small set screw in the middle. Just turn in counterclockwise to reduce the pressure at which the compressor kicks out.

Casey

[93GMCSierra]

From all I have seen a true R12 system that has not needed or been tampered with will cool a lot better then a R134 system, has anyone else seen or noticed this?

[Robyn]

The 134 system in my 95 DaHooooley is factory except for the replacement compressor and hoses I installed last summer.
It will deliver air from the dash vents at 38F at 85F ambient.

I am not a fan of 134 either and prefer to use envirosafe replacement materials such as their universal replacement chemical that can be used in either a 12 or 134 system.
This stuff is a hydrocarbon based refrigerant and requires only about 1/3 the amount to run things happily. This product is also happy with all the different oils out there too.

The overall system size needs to be larger to use the 134 especially the condenser due to 134's different pressure/ temperature curve from that of 12

The envirosafe requires lower pressures on the high side to accomplish the thermal transfer.

The low side pressures are closer to 12. This makes less work for the compressor.

The envirosafe material is non flamable (Under normal environments) and has a pleasant pine odor to identify a leak into the passenger compartment.


The 134 system can do a fine job as long as the system is working properly and the charge is right up to snuff and the condenser and evaporator are clean and flowing air well.

The best systems by far were the GM R12 STV systems (suction throttling valve) These were installed on the big boats in the 70's

The CCOT (Clutch cycling orifice tube) setups came out in the pickups and the smaller cars in the 80's
This system simply cycles the clutch with a pressure switch and the refrigerant flow is controlled by a small orifice tube installed in the evaporator inlet.\
These were far cheaper to produce as compared to the STv systems that had an Thermostatic expansion valve to control refrigerant flow into the evaporator and a suction throttling valve to cut back the flow to the compressor when the evaporator temp dropped too far.
The compressor ran all the time the system was in AC or defrost mode.

The STV systems were very efficient and would if tweeked produce air flow at the vents at very low 30's temps.

I have seen caddies and big Olds systems blow 34F. Risky at low blower speeds of having an ice over on the evaporator.


best

Robyn

[More Power]

My 1993 service manual (R-12 service info) indicates that the Low Side pressure cycling switch cycles at 22-46 psi (opens at 22 psi or lower and closes at 46 psi or above). My 2001 service manual indicates the Low Side pressure cycling switch opens at 21-25 psi and then closes at 38-42 psi.

The R134a converted A/C system in Lil Red has been doing well with the R12 Low Side pressure cycling switch for more than 3 years now.

There's a comprehensive article available to subscribers in the archive (http://www.thedieselpage.com/members/archive/airconditioning.htm) that discusses R-12/R-134a conversion.

Jim

[Robyn]

The cycling pressure is not the issue.

The older trucks with R12 systems dont seem to cool as well with 134 as the new ones.

The issue is the size of the condenser and evaporator. 134 is not nearly as efficient as 12 and so goes the battle.

Use envirosafe and install it by the companies directions and your 12 system will again be a happy little camper and your AC will blow nice and cold.

Best

Robyn

[CleviteKid]

Envirosafe website:

http://www.es-refrigerants.com/products/w/id/173/t/6-ounce-refrigerant-w-dye-can/related/true/details.asp

Clicking on the MSDS, the properties are quite close to pure propane. Just realize that the sweet pine smell you get in the cab from a leak can burn up just about as fast as last years Christmas tree. Might be good to institute a NO SMOKING policy in the truck. ;)

[DmaxMaverick]

Propane is nothing new. Most of the R-12 "compatible" stuff from Mexico is propane (Enviro-Safe is just "less stinky" propane). I quit preaching that point a long time ago. People just don't listen, and go for the cheap. If you never have a leak, you'll never have an issue with it. It works very well, but comes with chances of disaster. And, it isn't legal in many, of not most/all states, for use in on-highway R-12 system vehicles, or domestic dwellings. It's a little more "environmentally safe", depending on what we mean by environmental. I wouldn't consider it environmentally safe, in my personal environment.

Another thing to consider is why a person is converting their system from R-12. Usually, it means an older, less than healthy system, with leak(s). I know of several folks who won't fix minor leaks, if they can get the refrigerant cheap enough. Just top it off every so often.

There's no substitute for R-12. An R-134A conversion is a distant second. Unfortunate, but that's just the way it is.

According to Enviro-Safe's website, their refrigerant is NOT to be mixed with any other refrigerant. It is not a replacement for R-12 (it's unlawful to replace R-12 with ES). Although I'm sure there are many folks who do it anyway.

[JeepSJ]

I have read a lot of good information over at the forums at www.ackits.com. There are a lot of industry people that frequent that board and they are not afraid to tell you how they feel about the "alternative" refrigerants. They also have a lot of good information on system maintenance and converting from 12 to 134.

[Robyn]

The envirosafe products are certainly flamable under the right conditions but so is 134A. (Also has reactivity issues under certain conditions)

I would not be at all worried about the issue of fire especially when the largest percentage of vehicles are gasoline powered and carry anywhere from 15 to 40 gallons of the stuff in a tank that is none to strong.

The small amount of refrigerant in an average system (4 Pounds approx) is in my opinion not much of a threat considering that its caged up pretty well.

Obviously if one were to smell the pine scent in the cabin it probably would not be a great idea to light up. :eek:

By the same token if one opens the car door and smells gasoline the urge to light up a smoke should probably be curbed until the area can be well purged of any fumes.

The product is certified as a replacement for either 12 or 134a

The thing that disturbs me a lot about 134 is that you cant smell it and the chemicals it contains are nasty stuff especially if inhaled.

I justg went back over the MSDS on 134 and there have been some changes from what I read a few years ago.
Originally the stuff was pegged as being quite toxic other than displacing oxygen.

I am not too certain that the current MSDS may have been amended to satisfy the current push towards earth friendly chemicals. Hmmmmm

If it was nasty then it should still be me thinks ?????????/ :confused:

I dont really think any of the stuff is totally safe but when its contained where it is supposed to be it does the job.

Now an interesting point, R12 if exposed to fire or high heat such as what might happen in a car fire will give off Phosgene gas which is some nasty stuff.

Just a point here.
I do use 134 in newer systems that came with it. The stuff is easy to work with and does a fine job in a system that was designed to use it.

I personally have had poor results converting an R12 sytem to run the 134a
The overall performance of the 12 systems running 134 are less than optimal IMHO.

Using the envirosafe product produced exceptional results with zero reliability issues. *(no failure of seals or other components)

Bottom line, If one feels that 134A presents a safer overall condition, by all means use it.

I will my self use R134a in a newer system and the envirosafe products in all older stuff that was designed for R12.

The Key to converting from 12 to ES is that the system must be converted to 134 first.
This is a play on words and a political issue. The conversion is basically nothing more than replacing the access valves with the newer style ones for 134.
The rest of the system is the same as a 134 with the same sort of components.

After all if you can install 134a in the system and its ok and you can use the ES to replace the 134 in a system designed for it then what is the issue.
This whole thing is a nightmare of legaleeeeze to satisfy environmental laws that were written by people who have zero knowledge of refrigeration.

In speaking with the folks at ES some time ago they were very helpful as to how to properly handle this issue.
In keeping with good protocols I will not and do not advocate breaking the laws as they apply.




Just my 2 cents worth

Robyn

[DmaxMaverick]

......The product is certified as a replacement for either 12 or 134a......

It isn't. Read the fine print. Their fine print. The disclaimers satisfy lawyers, but can be misleading. They are selling a product, and assume no responsibility for misuse. This is not unique to this product.

Also, I think it is a very bad idea to have the pine scent. The "rotten egg" scent in many other chemicals is there for a specific reason. They could make the scent less offensive, but don't. Propane and natural gas have no natural distinct odor, so it is added to identify a leak. They can make it smell like anything they choose. A "pleasant pine scent" could, and may very likely, deter someone from taking a leak serious. R-134A is MUCH less volatile/combustible than Enviro-Safe or propane. Most chemicals are combustible in the right situation (even fire retardants/extinguishers). One specific, is asbestos. It is labeled as non-flammable, but the product warning also states it is toxic if it burns. Many products are the same way.

[Robyn]

Maverick

Good points for sure.
I was just doing some more research on the different refrigerants and found that Australia has gone to the HC refrigerants almost exclusively.

The tests conducted conveyed that the probability of a fire was very low.
The product when introduced into the passenger compartment under very ideal conditions that would favor a fire did not produce an ignition from any onboard systems.

The same tests with a burning ciggy butt did not ignite the product.

Tests were run with a catastophic failure of the liquid line coming into the evaporator. This resulted in a huge white fog of refrigerant and oil mist entering the cabin. The test was staged with an ignition source capable of causing a flash fire. The result was a overpressure of the cabin the blew out some of the windows thus allowing an influx of cool fresh air.

The bottom line was a few singed eyebrows and hair but no serious threat as compared to other possible hazards that present while driving and automobile.

Also In researching this issue the amount of Lobbying and $$$ spent to promote the use of 134A and an exclusive product tells me that there is certainly ill intent afoot here.

Companies that produce the 134 Product are feathering their nest via the legislative avenue rather than by its safety merits.

Just as usual we are taking it in the shorts again :(

I sent ES an email and asked severl questions. I will post whatever response I get back from them here.

Best to all


Robyn

[93GMCSierra]

Take this as it is, uninformed and speculative, when refrigerants first came out, they are patented, how long does that patent last? when that time frame is up exclusive control is relinquished so its much better to come up with another "better" product and to discredit the old product. And of course put down any up an comers that produce another different product.

[Robyn]

I wrote Envirosafe an email this morning and here is what I got back from them.

Below is the response and below that is my original email


If an R12 system has been retrofitted to a 134a system, at that point it is a 134a system. Then Enviro-Safe can be used in that sytem because it is no longer considered an R12 system.



From: cloudmt.ranch@bigborecanyon.com


To: contact@es-refrigerants.com


Subject: Envirosafe 12A


Date: Wed, 30 Apr 2008 07:51:17 -0700



Hello



I have used your products many times of the years and it was my understanding that this was the best (Only) replacement for R12 in auto systems.



Now I am understanding that this product can't be legally used in mobile systems that formerly used 12 ??



If this product is designed to replace 134A which is the common chemical used in mobile HVAC systems then what is the issue with using the ES12A to replace R12 in a mobile system.



The R12 system can be converted to 134A which leaves the end user with a sorry performing AC system at best.



The ES12A in the the 134 system will do a fabulous job and also does exemplary service in a R12 system.



Can you advise us on this issue and what exactly we need to do to take good care of our good customers.



I personally can not in good faith convert an R12 system to 134A and charge a customer for it considering that he/she will be very unhappy with the level of cooling.



The customer places a great deal of faith in their mechanic and expects results in direct proportion to the amount of dollars spent.



Please advise



Robyn Church

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[cwillis]

I've been reading alot of good things about HC-12a, the gas the europeans use. . . .

is this enviro safe stuff similar to that?

[arveetek]

I used to run propane in my a/c system on my '81. When I first realized that the aftermarket refrigerant alternatives were propane, I made an adapter to fit on my LP bottle and hook to my a/c guages. It worked great! It was one of the best a/c systems I ever had.

I wasn't concerned with the flammability issue all that much. I did change my mind about using LP one day when I was topping off the system with the engine running. A little vapor got sucked into the air cleaner and the engine sped way up. It was then that I thought about a possible unsafe scenario: perhaps one day I or my wife is sitting at the stop light with our foot on the brake. All of a sudden, an a/c hose bursts or the compressor seal lets go. LP gets sucked into the intake system, causing the eninge to rev up and the truck to surge forward. Either we rearend the car in front of us or we end up in the middle of heavy traffic. That's when I decided to go with 134.

I converted to 134 a few years back and have been very happy with the results. I have found that taking the time to remove the evaporator core and clean it out is the key to being happy with the conversion. Any vehicle that came with R-12 originally is several years old, and there is bound to be a bunch of dirt collecting in the evaporator area. Mine was caked full of nasty stuff. After cleaning out the evaporator and adjusting the low-pressure switch (which was set around 45 psi with my R-12 system), it cools great! I'm very satisified with it's cooling abilities.

Casey

[afgunn]

Did not expect this to get so technical when I created the thread but since we have gone there, I will try to remember a question I had when I got my automotive and commercial licenses for handling refrigerants. R134-A (and all the others) was developed to "save" us from chlorofluorocarbons (CFCs). As I am sure all of you know, CFCs are "supposed" to be depleting the ozone layer that protects us. The only question that was never answered or explained is how these molecules that are HEAVIER THAN AIR rise up to "destroy" the ozone layer!? But, hey, don't ever let facts stand in the way of "protecting the enviroment"! And some one had better hurry up and start catching sea foam (created when ocean waves lap and break) because that is releasing many times more ozone destroying molecules than ALL the CFCs ever released combined!

Alar on apples - not used in the US but this did not stop the scare that put many apple farmers out of business in the US

DDT destroying eagle eggs - never proven but, millions in third world countries have died because a very low priced and very effective pesticide was removed from the market

Global warming - yep, ever since 1850 - this time. And this is the 10th cycle. And guess what, man was not around the previous 9 times!

Ethanol - yea, let us starve some third world countries while we "save" the enviroment with a product that takes more energy to produce than you get and then get 25% less mpg!

And where is BIODIESEL!!!!!!!!! How about some subsidies for that! Maybe that would help MORE than 3 states!

OK! I am done ranting... For now!

[93GMCSierra]

Did not expect this to get so technical when I created the thread but since we have gone there, I will try to remember a question I had when I got my automotive and commercial licenses for handling refrigerants. R134-A (and all the others) was developed to "save" us from chlorofluorocarbons (CFCs). As I am sure all of you know, CFCs are "supposed" to be depleting the ozone layer that protects us. The only question that was never answered or explained is how these molecules that are HEAVIER THAN AIR rise up to "destroy" the ozone layer!? But, hey, don't ever let facts stand in the way of "protecting the enviroment"! And some one had better hurry up and start catching sea foam (created when ocean waves lap and break) because that is releasing many times more ozone destroying molecules than ALL the CFCs ever released combined!

Alar on apples - not used in the US but this did not stop the scare that put many apple farmers out of business in the US

DDT destroying eagle eggs - never proven but, millions in third world countries have died because a very low priced and very effective pesticide was removed from the market

Global warming - yep, ever since 1850 - this time. And this is the 10th cycle. And guess what, man was not around the previous 9 times!

Ethanol - yea, let us starve some third world countries while we "save" the enviroment with a product that takes more energy to produce than you get and then get 25% less mpg!

And where is BIODIESEL!!!!!!!!! How about some subsidies for that! Maybe that would help MORE than 3 states!

OK! I am done ranting... For now!

Yup about what I was getting at.

[Robyn]

I do not wish to turn this very informative thread into a political dabate, but the evidence is there to support the fact that so many of the save this or that is really only about placing control and $$$$$ in certain groups pockets.

I have mixed feelings about how the CFC"S can get into the very high altitudes.

The process is far more complex than just rising up and doing a dirty little job of ruining the Ozone.

If indeed this is happening then the CFC"S must be going through a change of state after being exposed to the atmosphere and sunlight.

Possibly the chemicals then morph into or breakdown into something that can attack the ozone.

R12 as it comes from the canister will settle into the lowest spot it can find and there it will stay.

Now, just possibly the reason all this bad stuff happens is because the average layperson has absolutely no idea what makes air conditioning work in the first place, so this makes the situation ripe for misinformation to propagate easily.

A case in point, a very nice lady recently told me that she really loves her home AC but still does not feel totally comfortable with it because the air has "That Stuff In It"

I asked her, "That Stuff"?? "well you know, those chemicals that hurt the environment".

Hmmmmm, this person actually believed that the air coming from her houshold vents is laced with chemicals and that is what makes it cold. :eek:

OMG I gave her a fairly indepth lesson with drawings and explanations on just how AC works.

She gasped and replied, "Those environmental people told me that my AC was not safe and my children were all breathing toxic chemicals every time we used the AC to cool our home"

This is only the tip of the iceberg me thinks.

I further explained to her that if the "Toxic chemicals" were in fact coming out of the system it would not be cold very long and would soon cease to work.

I have heard this sad tale several times over the years from fairly well educated people and it just makes me wonder how many people are being led down primrose path with many BS stories about sooooooo many things.


This is gulability at its worst. The sad thing is that there are people who will take advantage of others to promote an agenda.

Scams are everywhere and make a lot of money for a lot of people.

I wont say that the limiting of the use of CFC's is totally bad but I am suspect of those that are pushing hard on these things. I am not a chemist and dont fully understand all the chemical properties of these things. I do however understand that he who holds the pot of gold makes the rules and runs the show.

Getting back to the spirit and intent of this thread.

I am in the process of setting up the AC system for my Hummer replica kit and the system I am using is a Vintage Air Gen II heater AC system.

I am having to mount the condenser on the roof rather than in the front due to space issues.
Bottom line here is I WILL use 134A in the sytem for a few reasons. The compressor is an R4 unit that came on the 6.5 diesel and the VA unit is designed to work with 134A.

The best reason I can think of to use the 134 is that I can pick up a pail of the stuff at the NAPA store and its fairly cheap.

I have the tools to work R12,22,134 and a few others so that is not an issue.

If the system is designed to run 134 and perform well, its the easiest product to get and use.
I still believe that an older 12 system can benefit greatly from the HC replacements.

Stay cool. :D and be safe

Robyn

[afgunn]

Sounds like some people are getting "taken" in order for a company to convert their system or sell them a new system with "different", "better", "friendlier" freon. Have not heard of this but, not surprised either.

I am fairly ignorant (but not stupid). Could you expound a little on the Hummer Replica Kit? What chassis does it fit and what vehicles can be used? Sounds interesting!

Yes, the availability and comparative low cost of R134 is why I converted. I will know this summer if it will cool well enough or not. We can see day of 100+*F. Usually, in a R134 system the evaporator and condenser are larger to improve the efficiency of the R134 to about the R12 level. My 68 mustang used to spit frost from time to time - will never see that again!

One more rant. Do we really think that India and China are going to use a more expensive and less efficient freon than R12?! Like they are going to really care about the hole in the ozone! Ok, I am done - again.

[Robyn]

You can be sure that countries like China and other deveoping nations are not going to give a rip about the Ozone.

The Hummer replica kits are generally designed with a 130" wheelbase GM pickup Or Burb being used as the donor vehicle.
I used an 82 Burb 1500 4X4 for my chassis.

The Badlands R/T is the Kit I bought. There is also the Urban Gorilla

The Badlands was available from Classic Roadsters II and the Urban Gorilla is made by Urban Mfg co I believe.

There has been several of these kits made by various companies.

Badlands R/T --- Classic Roadsters
Bumvee -------- Tatonka co
Catvee---------- Canadian all terain vehicle co
Alleycat--------- Not sure but it came from Texas
T Rex ----------- T rex truck company
Storm warrior----- UK company and is a smaller rig than a real hummer
A couple kits built for the Jeep CJ and wrangler series

Several of these companies no loinger exist due to many things including AMG and their band of lawyers.

Some were bought off and others simply could not make a go of it.

The last I heard was that Classic Roadsters was being sold.
As far as I know the Urban Gorilla is still being produced.

There is also a company that sells plans to build your own kit from scratch. "Tremor MUV "

If you desire more info have a look over at H1forum.com

If you go to the showcase for replicas you can find my build there.

Robyn