Proper propane fill procedure on AC

[Ed Bighi]

All right guys, whoever out there knows all the tips and tricks to using Propane or Propane/Isobutane properly, please come forward and enlighten us. What is the proper way to put it in. The proper way to modify the nozles on the bottles (pics), the best ratios, the proper way to fill it, etc... For example, upside down or right side up (liquid/gas), and other things like that. Also, if there are any modifications that need to be made to the expansion valve, what needs to be done so that the evaporator core does not freeze up. Basically, if anybody out there has plenty of experience in this area, please give some pointers.

[Wayne 962]

Aren't there plenty of better (non-flammable) alternatives out there?

-Wayne

[RickM]

Ed,

Steve W uses a Propane cocktail.... R12 Substitutes? Any one using them?

Seems many of the alternatives are flammable. Including the popular Duracool.

[singpilot]

Most of the people that use propane or butane are in Tijuana or dead.

[Emission]

Is my "Freeze 12" fill flammable?

[Ed Bighi]

Actually Wayne, after much research, I have come to the realization that there aren't. Especially when one is trying to do the right thing for the environment. Not to mention staying cool. And for those that doubt the safety of the whole enterprise, go here www.greenchill.org. Look up the scientifical studies done on it. Very safe indeed. Though over here in the US, where fear is a hobby and dupont has influence, there is plenty of BS going around. While it can be considered dangerous in a theory, in practice it has been extremely safe. And for those that don't know, R134 is flamable under compression.

[Rot 911]

I don't know why it would be anymore dangerous than pressurized gasoline in rubber fuel lines.

[Steve W]

More than you ever wanted to know:

http://www.vettenet.org/acfaq.txt

[Ed Bighi]

Steve, I read that thing already. I need what that does not say. Like do you put the propane as a liquid or a gas. Invert the can or not. How has it affected the expansion valve? Do you need to tweak it to cope with the super low temperatures? Basically what I am looking for is how this applies to our cars. Oh, and how are your results?

[Steve W]

Ed, my system works b*tchin. Gas or liquid, I don't think it mattered too much in my case. I screwed an ac hose adapter to the end of a propane torch tip with a pretty small hole drilled at the tip, and I think I put it in upside down as a liquid. Just don't flood it in as a liquid too fast. Also be aware that by weight, if a system normally takes 36 oz of r12, you only install about 14oz, (don't remember the exact weight conversion) of a propane/isobutane mix.

I drilled a very small hole out of the propane torch tip to open it up. A standard propane tip hole is smaller than a strand of hair, and I didn't want to wait two hours for the thing to empty. I also drilled out the check valve on the underside of the torch adapter. I removed the screw on flame shroud at the end of the torch, and retreaded the end to match the threads on my ac hose. I screwed one end of the hose onto the end of the rethreaded torch, and screwed the other end onto the low side ac valve. Turn on the torch valve to release the gas into the system.

For isobutane, use about 20% by weight, and I used MSR's brand from Sport Chalet here. It is about 80% isobutane and 20% propane. The top of the can is pretty much identical to the tops of old R12 cans, so my old R12 ac adapter worked fine.

Check the high and low system pressures after you are done to optimize.

[Ed Bighi]

What pressures should I be chasing on the high and low side? They are probably going to be lower I presume. Probably lower than R12 and a heck of a lot lower than the usual 134 numbers. I gotta go find an old R12 hose. Somebody is gotta have one.

[Steve W]

I don't really remember as I did this quite a while ago. It should be similar to R12 if you use a 80/20 mix. If I recall, on my truck, it worked well at around 210/35 high/low.

[Ed Bighi]

Sounds normal Steve. Are you having any problems with the evap core freezing up?

[RickM]

BTW, at the bottom of this link page is a chart of the EPA accepted and unaccepted refrigerants. Notice some of the ingriedients.

http://www.epa.gov/ozone/snap/refrigerants/macssubs.html#note5

[Steve W]

Originally posted by Ed Bighi
Sounds normal Steve. Are you having any problems with the evap core freezing up?

No, the evaporator themostat should be taking care of modulating that.

[banjomike]

Start by lighting up a cigarette...

[skip several steps]

have your wife call 911

or just ignore my advise altogether!

[Wayne 962]

Originally posted by Kurt V
I don't know why it would be anymore dangerous than pressurized gasoline in rubber fuel lines.

Hmm, gasoline is a liquid at room temp, propane is a gas.

Admittedly, I am not a cooling system expert by any means...

Are there any DIY articles out there for AC conversions?

-Wayne

[Ed Bighi]

Originally posted by RickM
[B]BTW, at the bottom of this link page is a chart of the EPA accepted and unaccepted refrigerants. Notice some of the ingriedients.

Rick, there are some very weird things about the Eternal Pain in the Ass (EPA) and the way they look at refrigerants. For instance, why do they require R134, which by their own account, does not affect the ozone layer, to be recaptured? After all, it's supposed to be safe for us right. Besides, all it causes is testicular cancer and who needs testicles? But at the same time, you can spray 134 freely all over your keyboard to dust it by using a canned duster. That's what's inside those after all. But you can't route a pipe from one of your R134 nozzles and route it to your keyboard. The truth of the matter is that in fact R134 is toxic. Much more so than, say, propane. After all, would you cook with something highly toxic? But don't listen to me. Go dig up your own dirt on R134 which is far from a perfect solution to R12 in not just reduction of pollutants, but in cooling as well. Besides, the only issue with propane is flamability, which is also present in R134. Now that would be the concern of the DOT, and not the EPA. So why is the EPA sticking their nose where it does not belong. After all, all they are supposed to do is to look after pollution issues. Maybe because Dupon't likes it that way and lobbies hard. Or maybe because the MVAC repair industry does not like the difficulty of capturing many different elements? Not to mention losing some potential business. After all, I only started paying for AC service when R12 stopped being sold to non-licensees. Never mind the fact that there is no pollution problem from venting propane, or LPG which are naturally occuring substances, like farts. Bottom line, I stopped listening to the EPA a long time ago. Especially when Europe and Oceania, are head deep in phasing out CFC's, including R134, and going towards HC's for refrigeration. Even Greenpeace supports the use of Propane for refrigeration. R134 will not be around for as long as people think. Not only for pollution and toxicity issues, but for performance issues as well. But the hell with it as far as I am concerned. Last time I checked, propane isn't a controlled substance and for good reason. After all, the DOT lets us buy it, put it in our trunks, and drive with it. And if it finds my way into some pipe in my car, oh well. After all, neither is alcohol supposed to find its way into our own pipes when we drive, but who is following those rules. Neither am I supposed to speed for that matter.

Steve, the reason I mentioned the evap freezing up, is that propane seems to cool too good and some people end up with outrageously low vent temps until the thing freezes up. But I guess that with the limited size of the condensder in the 911, that won't be a problem. I guess I have to try. I should probably clean the condenser anyway.

[Elombard]

fascinating - keep us posted. What about using the Freeze 12? Would that be an easier fill??

[RickM]

Ed, You make many excellent points. At the end it depends on who's lobbying who the hardest.

As mentioned before just about every R12 alternative (if not all) is flammable.