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AC not cooling that well and need R12

Started by jsilvidi, 13 August 2010, 02:56 PM

AC not converted from R12

Keep R12
6 (54.5%)
Convert
5 (45.5%)

Total Members Voted: 6

alabbasi

#30
Quote from: thysonsacclaim on 16 September 2010, 10:03 PM
Why do you continue to argue instead of calling your local EPA branch office?


I don't need to, I'm not trying to find a cheap alternative to R12, it's cheap already and I have plenty of supplies of R12 and R406a. besides the website is quite clear.

Quote from: thysonsacclaim on 16 September 2010, 10:03 PM

The companies were trying to get SNAP approval so people would not have to alter their systems (ie change fittings).


Statements such as this concern me. No matter what refrigerant is used for retrofitting, fittings MUST be changed and the system must be labeled. It is illegal not to do so and you could contaminate existing supplies of refrigerant.

Quote from: thysonsacclaim on 16 September 2010, 10:03 PM

"Why is it legal to use hydrocarbon refrigerants as CFC-12 substitutes in industrial process refrigeration, but not elsewhere

Emmm....maybe it's because your not belting down the road at 70mph in a walk in freezer? That's like comparing apples to oranges.

Quote from: thysonsacclaim on 16 September 2010, 10:03 PM

Again, here they are referring to it as a direct replacement, without modifications. It is no longer legally a CFC-12 system when you convert it. As far as

That's the Loophole, I'm referring to to the fact that it's not a legal R12 alternative because the EPA has not received sufficient data to address safety issues.

Quote from: thysonsacclaim on 16 September 2010, 10:03 PM

Do yourself a favor and make the proper phone calls. It took me about 15 minutes to get an EPA agent on the line and another 5 minutes to ask him these questions.

I've done myself a favor by buying enough R12 to support all the cars that I own that need it. If I need more, then i'll buy more as it's readily available.

Quote from: thysonsacclaim on 16 September 2010, 10:03 PM

Out of curiosity, I asked further about venting the gases. The agent said hypothetically, if you filled your system with air (like that we breathe), the moment it is charged into that system, it can legally NOT be vented, even though it is completely harmless. Again, it is about semantics and legalities.

Yes it's illegal to vent any refrigerant. It's a safety measure because most refrigerants are either bad for the environment or bad for you. If there is no blanket law, who is to say what you're venting? It will be even worse then pretending that an R12 system is an R134 system because you've changed fittings.  How did you get your license without knowing this?

As it's illegal to vent, the system must be recovered and therefore, by law, if you retrofit a system, you must fit unique fittings to that particular gas and label accordingly. It's not just a matter of legality, it's a matter of integrity, if you don't then your actions to result in the contamination of someones supply.

Here's a listing of fitting and label requirements for motor vehicle a/c.

http://www.epa.gov/ozone/snap/refrigerants/fittlist.html

Duracool, OZ12 and ES-12a are not listed here because it's not considered a motor vehicle a/c refrigerant. Neither is R290 (propane) or R600 (butane) which are recognized as refrigerants but not for automotive applications.

You can disagree, but you can't change the facts.



With best regards

Al
Dallas, TX USA.

thysonsacclaim

#31
I've been a little busy, so I haven't had time to reply. However, here are some points to address your assessment of propane as a proper replacement in R134a and R12 systems:

Quote
I don't need to, I'm not trying to find a cheap alternative to R12, it's cheap already and I have plenty of supplies of R12 and R406a. besides the website is quite clear.

That's fine. However, the issue for me is efficiency and the fact that I'd prefer not to use R12. Also, propane has superior cooling properties and requires considerably less power to compress. Therefore, it cools better and would result in nominal energy savings (i.e. better mileage, and less strain on the AC system).

QuoteStatements such as this concern me. No matter what refrigerant is used for retrofitting, fittings MUST be changed and the system must be labeled. It is illegal not to do so and you could contaminate existing supplies of refrigerant.

Fittings must be changed for ozone-depleting and global warming coolants. The EPA has not mandated fitting specific changes for second generation replacements in MVAC applications, which is a lapse on their part. The E-S kit does come with a label indicating it is propane. Regarding contamination, it depends. You could easily take it to anywhere that removes HVAC coolants or to those MVAC places that remediate gases. The contamination issue is when the gases they suck out are to be recycled, or if they would interact with each other. Remediation doesn't have this problem, because it is generally not re-used.

Also, it seems E-S does come with R290 standard fittings and does not use R134a fittings. I didn't realize this before. However

QuoteEmmm....maybe it's because your not belting down the road at 70mph in a walk in freezer? That's like comparing apples to oranges.

Perhaps you should read up further on flammability and combustion. You argument is just as silly as the hydrogen argument. For your information, to be combustible, propane requires oxygen. Thus in the compressor alone, it would never ignite. It could ignite if it leaked, so I'll give you a scenario.


1: Assume the gas leak is massive, and all leaks out almost instantly.
2: Assume it stays in the engine bay, even though there would be at least 1 fan running to disperse the gas (ie push it out) and that the positive pressure created from the expansion of the gas would allow it to be pushed out. So we're assuming the propane stays in a sealed chamber.
3: Assume a pilot, spark or fire is in the bay.
4: Assume the amount of R12 needed is 2.5 pounds

First, you need to know that propane combusts with oxygen just like most other alkanes:
C3H8 + 5 O2 >>> 3 CO2 + 4 H2O + Energy (in the form of heat)

Second, you need to know that in order to ignite propane, you must achieve the critical concentration ratio of oxygen to propane. This varies depending on the ambient temperature and relative humidity. However, it is widely accepted to be between 3% and 10%. In other words, there must be 3-10% of propane in a given area in order for it to possibly combust. Since I like doing my calculations conservatively, we'll go with 3%.

For the record, I prefer working in metric units when possible, so that's what I'll be converting to when necessary.

About propane:

1 Gallon of Propane in a tank Expands to 36 cubic feet
Therefore, 1 gallon of propane = 36ft^3 = 1019.40 Litres

This is consistent with the fact that propane expands 270 times when going from liquid to gas phase.

Now that we have a figure for how much space propane will take up in the air, let's calculate the volume of a cube, which this propane will be released into.

Suppose the area is  36 inches deep, 18 inches wide and 15 inches high. Using the volume formula, we come up with 36in*18in*15in =  9720 cubic inches. 9720 cubic inches is the same as 159.282262 cubic decimeters. 1 cubic decimeter is the same thing as 1 litre. Therefore, the space in this model is 159 litres.

So let's assume this very tiny area is in the engine bay. The engine bay of most cars is actually significantly bigger than this, however.

This vehicle required 2.5 pounds of R12 when it used R12, now it uses E-S. .33 pounds of Enviro-safe is equivalent to 1 pound of R12. This is the recommended filling amount. So let's use a proportion to figure out how much E-S we need for a car that took 2.5 pounds of R12:

.33 pounds E-S     X pounds of E-S
-------------------- = --------------------
1 Pound R12         2.5 Pounds R12

Solving for x, we find that this vehicle will need .825 pounds of E-S, or 13.2 ounces, or 0.3903 litres.

Now understand that the density of propane is about 0.51 kg/L. So, accordingly, propane weighs 4.2 pounds per gallon. So, now we need to convert the pounds of propane to liters.

The density of propane at STP (standard temperature and pressure) 25 degrees Celsius is .493 grams per cubic centimeter So, we have 1 litre with a mass of 493 grams or 1.1 Pounds. Using a proportion, we can find out how many litres of propane .825 pounds is:

.825 pounds Propane    1.1 pounds Propane
--------------------------   = -------------------------
 x litres                           1 litres

Solving for x, you find that .825 pounds of propane is .75 litres.

We know 1 gallon of propane expands to fill 1019.40 Litres. 1 Gallon is 3.785 litres. Now, we can use another proportion to find out how much .75 litres pounds of propane would expand to.


3.785 Litres Propane        .75 Litres Propane
------------------------------ = -----------------------
1019.4 Litres Expanded     x litres expanded

Solving for x, you find that .75 litres of propane expands to ~202 litres.

Sounds bad? Well yes, if the propane were being stored as a liquid in a container. Propane expands to 270 times its volume when held in a standard tank. However, here we are talking about a compressor, which is not going to put the gas into a liquid state. This means the expansion will be less, but I can't say by how much. Probably around 10-30% less, given the pressure differences.

Given that 202 litres of propane would totally saturate our small space of 159 litres of space, it would be potentially explosive under the conditions I set forth. But would it actually explode?

I have uploaded one of several journal articles I found regarding this issue to my domain. Actually, there are several hundred papers published on this. Unfortunately, many are not yet in the public domain, which means unless you work for or attend a University, you cannot view them without paying money.

This particular article comes from the School of Mechanical and Manufacturing Engineering at The University of New South Wales, in Sydney. When looking, I chose European and Australian institutions over American ones, because the use of R290 (propane) is much more common in MVAC applications in those countries. However, the American journals pretty much say the same thing.

When looking for these, it is important to find articles not paid for by the hydrocarbon industry or the companies which promote HFCs. There is always a potential for confirmation bias in those papers. This particular paper is a good example of unbiased research and is pretty sound:

Usage and Risk of Hydrocarbon Refrigerants in Motor Cars for Australia and the United States

If you don't want to go through the statistics and calculus equations, you can skip to the bottom to the conclusion. I have copied it here for ease.

Abstract:

QuoteCommercial replacement of fluorocarbons in mobile air conditioning systems (MACS)
with typically HC-290/600a[60/40] and minimal precautions began in Idaho in 1993. R290/600a
has low environmental impact but mixed with air is flammable and frequencies for fire, injury
and cabin overpressure were predicted. No such accidents are known from 1993 to
mid-2003.
R290/600a suppliers consumption, representative MACS charges and charge termination
frequency were used to predict yearly total MACS numbers. Mid-2002 in Australia there
were 0.33×106 and at end 2002 in the USA 4.7×106 R290/600a MACS. Integrating over
time gave usage for Australia to the end 2002 as 1.09×106 car-years and to mid-2003 for
the USA 21.7×106 car-years.
The measured US fire, injury and cabin overpressure frequencies are less than 3.2 ×
10−7 per car year with high probability. This fire frequency is a hundred times lower than
predicted because most R290/600a leaks in MACS use are effectively nonflammable.

Conclusion:

QuoteThe number of mobile air conditioning systems using HC-290/600a in Australia
was 0.33±0.12×106 mid-2002 and in the United States of America was 4.7±
1.7×106 at end 2002. The usage for Australia was 1.09±0.36×106 car-years at
end 2002 and for the USA 21.7±7.8×106 car-years mid-2003. Tables 1 and 2 give
R290/600a MACS numbers and usage at dates from 1993 to 2003.
The predicted extra recorded frequencies of fire, injury and cabin overpressure in
Table 3 from using R290/600a MACS are low and agree but no such accidents are
known. The US usage shows that statistically there is only 1 chance in 1000 that
the true recorded accident frequencies are greater than 3.2×10^−7 per car year. For
fires this is consistent with the ignition probability being hundreds of times less than
used in predictions and most R290/600a leaks being effectively nonflammable.

The actual accident frequency and hence risk of using hydrocarbon refrigerant in
motor cars is much lower than predicted when commercial use commenced.

The most interesting thing is that they are essentially saying that while initially it was predicted that more accidents occurred, when they actually looked at the data from accidents in R290/600a vehicles, the number of incidents was lower. Furthermore, they say this agrees with their calculations that the ignition probability is extremely low.

Prior to that, it says the there is a 1 in 1000 chance that accidents will exceed 3.2×10^−7 per car year. In other words, there is a .001% chance that more than .00000032 accidents will occur. In the US, the population is 307,006,550, according to the 2009 US Census. For simplicity, let's assume every single person has 1 car. Therefore, assume 307,006,550 cars in the US. Also, let's assume they ALL use R290/600a.

The data reflected in this journal article suggests that with 307,006,550 cars using R290/600a, 98.24 explosions would occur per year (307,006,550 * .00000032).

QuoteYes it's illegal to vent any refrigerant ... How did you get your license without knowing this?

Yes, I know. My point is about the semantics of some of the rules. It could be a completely harmless gas, but still illegal to vent.

QuoteDuracool, OZ12 and ES-12a are not listed here because it's not considered a motor vehicle a/c refrigerant. Neither is R290 (propane) or R600 (butane) which are recognized as refrigerants but not for automotive applications.

Again, it is perfectly fine to use it for 134a conversion. In R12 conversions, you must effectively convert the system to 134a prior to use. As far as whether or not it is harmful to the AC system, no it's not. As long as the gas can fit the specs and is compatible with the seals and lubricants, there is no problem.

QuoteYou can disagree, but you can't change the facts.

I'm not changing the facts and not really disagreeing on anything, except the legality. I know propane is flammable. However, given the relatively low chance anything will actually happen, I'll take my chances.

In reality, everything will be fine and I'll have much cooler AC than R134a or R12 can provide.

Oh and by the way, how do you think they got the data from R290/600a use in the United States, if it were completely illegal to use? I don't know of any major car companies in the US that use it, meaning the data is from conversions (which is also what the article says).

Finally, quickly Google how often gasoline tanks in cars actually explode. You'll find out it is much more common than you would believe.

There is an article here that discusses this. It clearly says that in Maryland, in the year 2000, there were .25 incidents (fire/explosion) per 1000 accident vehicles. Maryland is the state with the LEAST number of incidents in the year. This is on page 169.

.25 incidents... 1000 accident cars. Apparently more common than you would like to believe. Definitely much more common than propane figures.

Furthermore, gasoline's ignition temperature is 430 to 500 degrees F, whereas propane will not ignite until the air reaches at least 940 degrees F. Do you really think you are going to have a flame that's 940 degrees without knowing it?

Finally, as if all of that were not enough, there is another article you can look at (also from Australia):
Hydrocarbon Refrigerants in Australian Cars

If you read this article, you can see it has references to others. These are at the bottom. They include these:

Insurance Risk for Hydrocarbon Refrigerants in Car Air-Conditioners

Comparative Performance of Hydrocarbon Refrigerants

KenM

I'm reading this discussion with interest, I am an a/c tech in Australia, haven't done automotive a/c for a number of years but I try to keep up with developments, it's more and more complicated these days.

Without knowing the circumstances,  I'm surprised and a bit disappointed at the apparent ready availability of R12 in the US, it should be 10 times the price of 134a to discourage its use. R12 hasn't been seen for years here,

it's totally unobtainable legally and any vehicle coming to a shop that still has R12 cannot be worked on until it is removed. (I think this is right).

HC refrigerants have been the cause of a number of injuries to a/c technicians here from explosions, there seem to be a number of reasons for this;

Technicians do not need to be licensed to work on these type of refrigerants. As industry here seems to be much more heavily regulated and licensed than in  the US, with the costs for employers that go with this, ( not

inconsiderable) it has been one of the points that the HC lobby is pushing to promote their product. However we have different legislation in regard to HC refrigerants in each state. Queensland for example bans HC

refrigerants totally for automotive uses. Other states have regulations that say HC refrigerants are not recommended but may be suitable for use in automotive applications 'with the recommendation or approval of the

vehicle's manufacturer' , or words to that effect. This has led to HC's being used but in a lot of cases it is being done but not advertised, i:e the vehicle's a/c is not being labelled as having a HC refrigerant present.

Problems then arise when a person takes their vehicle to a workshop to have the a/c checked and the staff go to work on it, not suspecting that it contains HC's. This is when people are being taken by surprise and injured.

At this time, no vehicle manufacturer in the world approves the use of HC's in their vehicles' a/c systems and none has any plans to do so, purely for the safety aspects.

In addition, no compressor manufacturer will warrant their product when used with HC's, as they have been linked with compressor failures.

Another reason cited here in Oz that HC's pose a safety risk is that the canisters it is being sold in do not have a left hand thread as required by relevant Australian Standards for flammable gases, making it easier for

backyard mechanics and weekend dabblers to put this refrigerant into a/c systems. In many cases, (the claim goes),  these people would not have the correct labelling etc to go along with a retrofit, nor the recovery facilities

to reclaim 134a correctly, leading to the 134a (or whatever was in the system originally) simply being vented to atmosphere.

There are a number of alternatives to 134a being tested at the moment, I read recently that GM will be using a new refrigerant (with a long name that escapes me) in all their vehicles from 2013 (presuming they are still in

business). The CO2 refrigerants could still have a role to play, despite the enormous pressures involved.

Adam you may know that the fellow who authored the articles you have posted links to, Maclaine-cross, is or was (don't know which) a university lecturer in the state of New South Wales here. He was for many years a

strong advocate for HC refrigerants to replace first R12 and then 134a. There is a you tube video of him conducting an experiment, you can find it by putting his name into the search feature. It's pretty tedious until the last

bit and the audio quality on the video is truly awful, you cannot understand a word he says but the pics are clear enough. In about 2001 he decided to demonstrate how safe the stuff was so he set up an experiment where

he sat in his car and sprayed some refrigerant into the car's a/c to simulate a gas leak into the cabin, and then he lit a match. Yep, kaboom. I believe that since then he has changed his views, don't know to what extent.

In summary, for my 2 cents I would say that HC's work well, no doubt about it but that the potential risks mean that they should be seen as a very temporary solution, personally I would use a blend in place of 134a, or god

forbid R12, despite the known problems that blends have with leaks. As I said I am not an automotive a/c tech so stand to be corrected on any aspect of what I have said here.

Cheers,

Ken

alabbasi

#33
I don't have time to read the information above, it's not going to convince me that propane is safe to put in your a/c system as i'm never going to assume that it will suddenly evaporate as soon as a leak appears. Things may happen that way in a lab but not in the real world.  

The argument reminds me of the whole sub prime mortgage cock up. You loan 1/2 million dollars to someone making $40 grand a year so that that they can buy a big house and flip it, then everyone is mystified when they fail to pay... who could have seen that happen?

Either the model that they used to assess risk was flawed or someone found a loophole.

Furthermore, if your not labeling or changing fittings while using a flammable gas, then one has to question the ethics behind that decision.

Ken, the US has banned the manufacture of R12 but existing supplies can still be purchased by a licensed individual and used. It cannot be bought legally without a license (unless it's for resale). The law states that the refrigerant must be recovered and not vented.

The market dictates the price. Eight years or so ago when I got my license, it was very expensive to buy as there were still many cars that used it. But as newest car that uses R12 these days is 18 years old, the demand is not so high and the price has subsiquently dropped.

In my opinion, it's a sensible approach as the stuff still exists. Whether it is stored in a jug at the bottom of a cave, or whether it's stored in an automotive a/c system does not change things much provided that it's not vented. Given that the number of cars actually using R12 these days is relatively small (most are either not working, converted or the car has long since been scrapped) and the relative high cost of R12, the vast majority of people that buy the stuff for their cars make sure that their system is leak free because it's the responsible and cost effective thing to do. Because of this, I suspect that the impact on ozone depletion from leaky R12 system systems (in the US) is probably very low these days.

I've heard the argument that chlorine evaporating from swimming pools would have a bigger impact but I have made no effort in digging any deeper there. It kind of makes sense to me though.

I'm not against blends or R134, I'm on my third jug of R406a and it's served me well on the MB's. I also run R134 in my 6.9 and it works just fine in that car. It did not do too well in the SL's and SLC's however so I went back to R12. R12 however is really the simplest product to use if you want to maintain a properly working a/c system as hose changes, flushing the system, changing oil or anything else is required.

With best regards

Al
Dallas, TX USA.

hvacmetalman

Don't believe all the hype about r12 being bad for the ozone, it is politcal, not scientific fact. the space shuttle causes more destruction to the ozone every time it is launched then a million cans of R12

The R12 systems will work fairly well with R134, however the pressures are not the same, R134 will eventually cause the system to fail because the R12 system was not designed to handle R134 pressures. R12 has a low side pressure of 25-50 PSI and a high side pressure of 125-150 PSI depending on outside ambient temp. R134 has a low side pressure that is close to that of R12, however the high side pressure can go as high as 350 PSI on a hot summer day and the R12 system was not designed to handle this pressure.

You can take the test and get your 609 certification online and that will allow you to legally buy R12 and charge your own auto AC system. Mainstream Engineering corporation is where you can study and take the test and it is done online there address is http://www.epatest.com/ 

koan

#35
Probably going to get on your bad side KenM but I have to disagree with you on a couple of things

In QLD HC  refrigerants are illegal, they were in NSW for a short period but never in VIC, don't know about other states and the territories.

As I understand the situation In VIC a license is required to work on auto A/C. The relevant legislation is worded in terms of recovery of gasses, not their use in auto systems. As my system had self vented its R12 over the years it seemed to me that I could legally use an HC gas without needing a qualification. Don't know if the manufacturer's recommendation part applies in VIC.

The organisation VASA, based in QLD is very vocal in it's opposition (one could say fanatical) to HC use in cars but last time I looked at vasa.org there was only one auto HC incident reported, another incident was a cool store in NZ but not auto related. I suspect the organisation is more interested in protecting its members turf than presenting an accurate assessment of HC gasses.

It's really is difficult to justify a ban on HC gasses in A/C systems on safety grounds, HCs are every where, BBQ bottles, LPG systems, fag lighters, some aerosol cans still use HC propellants and there are minimal, almost no accidents from their use.

There's a block of flats in my area that was damaged by an explosion recently. I used to live in them 40 years ago, there was a young lady I fancied across the court yard but sadly didn't get anywhere. The explosion in a second floor flat blew out a double brick wall and  three flats in the top floor above were demolished. It was reported as resulting from a leak in a camping gas cylinder - no way. Turned out the residents where boiling up some drug related concoction and things went astray. I experienced a propane ignition years ago, a bit of a whoosh, a warm feeling on the skin and shinged eyebrows.

About compressor failures being caused by HCs, is that what is referred to as "Black Death" where the entire system is choked with some black gunge? HCs were blamed for this but I believe it turned out to be a particular compressor using an unusual material for a seal which slowly disintegrated. It was a problem for that compressor no matter what gas was used but it was selectively presented as an argument against HCs.

Systems using HC should be clearly labeled but there is no requirement for incompatible connectors in AUS, again, as far as I know.  Unlabeled systems do present a risk of contaminating recovered stores of R134a but the risk of harm to technicians must be very limited. I would think there must be some pretty poor work place safety practices to ignite the HC gas during inspection and recovery considering what other inflammables are around . The dramatic picture on vasa.org of a two meter jet of flame erupting from the end of a hose while the technician looks on if horror is not going to happen by accident.

The incident you refer to by the NSW university lecturer was a foolish exercise, the video is worth watching. I think the incident occurred in SA during an attempt to demonstrate the safety of HC gasses to some invited overseas visitors. I happened to hear on the radio news he was found guilty of two breeches of work place safety laws. I wondered what the two breeches were and could only surmise the first one was for being really stupid and the second for being really fucking stupid.  

Being a "backyard mechanic and weekend dabbler" and sick of the yearly $200-300 payout to find the leak (she's fixed now mate!) and recharge of my A/C (this was in R12 days) I bough a couple of books on HVAC systems, read what I could on the internet, bought a vacuum pump and cheap gauge set, bought a more expensive gauge set because the cheap one was crap. I assessed the risk of explosion inside the cabin as minimal and decided an HC gas was safe. Went and bought a couple of cans of refrigerant. I rebuilt the system, flushed it, changed the oil, charged it with the required 330gms of Freeze 12 Minus 30, a local product (previously called HC12) and have not looked back.

koan
Boogity, Boogity, Boogity, Amen!

thysonsacclaim

Thanks everyone for chiming in your thoughts.

About this:
QuoteThings may happen that way in a lab but not in the real world.

The data from the crashes of hydrocarbon filled cars was from the real world, as was the crash data for gasoline explosions in cars  ;D

Contrary to what you might think, many times lab research is only done prior to conducting real world research. It is much better to observe things as they actually occur.

QuoteEither the model that they used to assess risk was flawed or someone found a loophole.

They didn't use a model, they used real world crash data.

In any case, I would never suggest someone puts any HC into their system without taking the proper steps. It needs to be labeled, it needs to have the fittings, it should be flushed out, and so on and so forth. No one has disagreed on any of these things.

QuoteDon't believe all the hype about r12 being bad for the ozone, it is politcal, not scientific fact. the space shuttle causes more destruction to the ozone every time it is launched then a million cans of R12

Unfortunately, most things become political. However, R12 has been known to deplete ozone for a long time. It is in every college chemistry textbook now and there are thousands of papers published on it. The scientific consensus on that is far higher than global warming. It's much closer to 100%, because it is very easy to show what those gases do.

QuoteAdam you may know that the fellow who authored the articles you have posted links to, Maclaine-cross, is or was (don't know which) a university lecturer in the state of New South Wales here.

He lit a match in a car knowingly filled with propane, unfortunately the audio is bad, so I can't see how much. I will say that the HCs come with incredibly strong odorants, to make you aware it is leaking. The odorants, just like those added to regular propane (the sulfur smell) are meant to be able to be smelled before critical air concentration is reached (3-10%). In this way, you prevent problems, should they ever occur.

QuoteIt's really is difficult to justify a ban on HC gasses in A/C systems on safety grounds, HCs are every where, BBQ bottles, LPG systems, fag lighters, some aerosol cans still use HC propellants and there are minimal, almost no accidents from their use.

I agree. As long as you know the potential risks, take care to be safe and respect what you are working with, you have no problems.

KenM

Hey all,

Koan, no worries, I'm not too sure what you disagreed with me about, I guess the general gist of my post was that HC's can be dangerous. This is an imprecise statement but what I guess I mean is that my main concern

would be from the point of view of a service tech coming along to a job without any prior knowledge and igniting refrigerant by accident. It's unlikely I grant you, for all the technical reasons that Adam has detailed very well

and also because there shouldn't be huge volumes of gas around anyhow. Consider though a large workshop, you have people doing all sorts of thing, welding, grinding etc etc, the potential is there. I'm not saying that

HC's should be banned and your own case is an excellent example. From the lengths you have gone to with knowledge gathering and equipment purchases you are far more down the track than a weekend dabbler, I would

have no doubt that your system would be safe, both for you and for someone else who you might happen to engage to work on the system since you labelled it correctly and they could see what they were dealing with.

I'm not sure of the regs in Vic and I'm not sure of the requirements for different connections (if any) for the use of HC's. (it would be sensible though and easy enough to do)

Thinking about it now, I must say I probably have approached this from the viewpoint of a licensed technician, and so to me the cost of one gas (and oils, hoses, connections etc) over another is not really a concern and

there being numerous refrigerants around I would choose a non flammable one for safety and because I can. You're right that HC's are everywhere, it seems to me though that people by and large know this and expect to

find flammable gas where it is found, and so take appropriate precautions as second nature, it's when you come across it unexpectedly that problems arise, to hammer a point.

I know what you mean about VASA, I didn't know that they are Qld based but I know they can be a pain in the arse and I have no doubt that in their opposition to HC's at least in part they are like a dog with a good bone,

work it for all it's worth. I'm not sure that they are really necessary, or perhaps shouldn't be in an ideal world.

I didn't hear about this 'black death' thing you mention, so I could be guilty of regurgitating incomplete or tainted information there, I had understood that the problems arose due to a solvent effect of the refrigerant that

washed the oil out of compressors. This can and does happen with any refrigerant if the system is not set up properly, perhaps I should do some more research on that.

In general, I don't understand this thing people go on with about 'contaminating 134a stocks' by reclaiming HC's by mistake. If you were going to reclaim gas for re-use I would think you would make damn sure what it was

and that it was in good nic. There are ways to do this before you mix it in a cylinder with other refrigerant. I wouldn't be buying reclaimed gas for my system in any case, it's not worth the risk.

Don't know how much cfc's the space shuttle puts out but it can only add to what's already floating around, not cancel any out. There is no doubt that R12 and many other gases are not good for the ozone layer and global

warming, the science is unequivocal on that.

And the one about swimming pool chlorine goes back to the early days of confusion about chlorine and fluorines, chlorine in this form is already quite volatile and easily breaks down long before it reaches the ozone layer.

Cheers, 

thysonsacclaim

QuoteAnd the one about swimming pool chlorine goes back to the early days of confusion about chlorine and fluorines, chlorine in this form is already quite volatile and easily breaks down long before it reaches the ozone layer.

This is 100% spot on. CFCs are broken down by the radiation in the stratosphere, which contains about ~90% of all the ozone.

Since they are stable until reaching the stratosphere, they reach it largely intact. However, when they do break apart, a single chlorine atom is released:

CCl3F >>>> CCl2F- + Cl-

The Cl has a minus sign because it has an unbalanced charge. In this state, it is a highly reactive free radical, which will go on to bond with oxygen that hasn't yet been turned into ozone.

Regular pool chlorine reacts quite differently. It is typically a salt and just like table salt, it dissolves in water because the two parts of the molecule break apart in water:

NaOCl (sodium hypochlorite/bleach) + H2O (water) >>>> NaOH (sodium hydroxide/lye) + HOCl (hydrochlorous acid)

The Hydrochlorous Acid is not very stable and the solution breaks apart, especially when exposed to sunlight, yielding Oxygen and more hydrochloric acid.

2 HClO >>>> 2 HCl + O2

Also molecular chlorine, Cl2, reacts very differently than Cl-. It is not as reactive Cl- because it has a balanced charge.

QuoteKoan, no worries, I'm not too sure what you disagreed with me about, I guess the general gist of my post was that HC's can be dangerous. This is an imprecise statement but what I guess I mean is that my main concern would be from the point of view of a service tech coming along to a job without any prior knowledge and igniting refrigerant by accident.

Since koan and I are both experimenting/using HCs in our cars, I'm going to look into it a bit further. I think all the major safety / legal stuff has been addressed, but I want to see if there is anything that hasn't been mentioned.

I have gotten in touch with Dr. Maclaine-Cross via (of all things) Facebook. We've swapped a few e-mail since then and he has offered to answer any specific questions I have. Since he is/was an obvious proponent of HCs in refrigeration systems, and did have that incident with the propane in the car, I think he'll be able to lead me to anything that might be of concern to us.

koan

#39
The VASA website www.vasa.org.au (not www.vasa.org as I posted previously) has been updated and redesigned recently and now seems to have toned down the rhetoric regarding HC gasses.

The "Hydrocarbon Safety Alerts" link lists alerts from four AUS states, two from New Zealand and their own alert. Of the four AUS state alerts, two (SA, NSW) refer to care the required with HC gasses, one (VIC) is a general materials safety document that doesn't specifically mention HCs and finally QLD where HCs are illegal in auto A/C systems. Accurate info not the fanatical ravings of the old site, good to see.

I also see on their major sponsors page Dupont is top of the list.

koan
Boogity, Boogity, Boogity, Amen!

Hemersam

My head is swimming! Is there no end to this discussion?
Hemersam

thysonsacclaim

QuoteI also see on their major sponsors page Dupont is top of the list.

Not surprising. Dupont was also behind the push for 134a, once they had a patent for it.

QuoteMy head is swimming! Is there no end to this discussion?

Sorry. I think the major points/issues have been made and I leave it up to the individual to make their own choices. My further questions (that I am asking Dr. Maclaine-cross) are more directed towards long-term issues (ie wear) and whether or not I represented his data here correctly or not. I'm fairly sure I have, but he published the papers.

QuoteThe VASA website www.vasa.org.au (not www.vasa.org  as I posted previously) has been updated and redesigned recently and now seems to have toned down the rhetoric regarding HC gasses.

I wasn't able to find things from them, but the extent of 'Research' done by most places consists of placing propane in a closed container and igniting it. Under these conditions, lots of things would catch fire.

It reminds me of the old story about Edison trying to prove DC was safer than AC by Electrocuting an Elephant.

Hemersam


thysonsacclaim

I really don't plan on pursuing the issue more unless I find something out that is actually drastically important and not already mentioned. Some things never come to a consensus, and I'm fine with that as long as everything is equally represented. I think everyone has made valid points.

There is more than enough information here for anyone to make a personal choice about what they want to do, keeping in mind safety and legality.

My primary motivation for bringing up this information is that there really isn't a lot of places online where you can find everything in one place. It took a lot of time for me (probably koan, too) to collect enough information before deciding to do a conversion for myself, and that is coming from someone with 4 years of formal chemistry education, in organic chemistry and hydrocarbons, which is very specifically related to the things that have been discussed.

That doesn't make me a expert by any means, and I am by no means an automotive guru AT ALL, but it goes to say that if I would go through this amount of time find out every detail, I would want it readily available for someone who doesn't have the same background as I do or anyone else who posted.

Point is, a lot of the information I did find is spread far and wide, incomplete or just plain wrong or hard to understand. By making a wealth of the information available all in one place, with multiple perspectives present, and because w116.org places so well in Google, it will hopefully help people come to their own personal decision on what they should do.

Having said that, I'd prefer the issue rests as it is. I will probably post my procedure with pics here or in another thread, once I get all the parts I need to do it correctly. Beyond that, I don't think anything else is worth mentioning and I do apologize if I have offended anyone.

Franky

#44
I brought this AC system back to life years ago with R12 thanks to the help from this forum. I had flushed it real good, replaced the expansion valve and accumulator, put mineral oil in it and R12 and was getting vent temps in the 30's. This lasted for months - year (I forget exactly how long, but it was for a good while). I don't drive it that often, but one day the compressor didn't cut on. Since I have other cars I let it sit for a while, but when I started working on it I realized there wasn't any or very little refrigerant in the system. I pulled a vacuum and it has a very slow leak, about 1 psi per day that I can't find so I added about 1/2 oz of dye and about 1/2 oz of mineral oil, pulled another vacuum and added the 406. Since it's a Keihn compressor, I was told that it can't be converted to 134 so my plan is to run the 406 for a while and hopefully find the slow leak, fix it and put R12 back in it. The problem is, after adding the 406 I'm only getting vent temps of 69 degrees at 2K rpm. The site glass is still very cloudy and the evap drain is dripping steady, but of course, not very cold. The compressor never cycles off and once I shut it down, pressures stabilize at 118 psi. Should I still add more 406 to get better vent temps and if so, how much or ??? Thanks in advance!
Furnace Replacement