Air Duster Cans as R-12 Refrigerant Alternative???

plaaya69

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#1
I was just wondering if anyone else heard of using air duster cans as a r12 refrigerant alternative since some contain Difluoroethane - R152A? I have accumulated about 10 cans of r-12 recently since I want to keep what the Supra originally called for and keep some future spares for when I put the a/c system back together but I was just wondering if anyone else heard of this, tried it or want to share their experience? I thought this was some kind of April Fools joke but I never really heard of it:



 

figgie

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#2
Why?

40 degree out of the vent is 40 degree whether it is R134a, r12, Ammonia etc.

There is a Toyota Service bulletin (and it happens to be sticked up on this forum) with how much r-134a to add and oil. This is DIRECTLY from Toyota since it still is a mandate to switch over to r-134a on cars that use R-12.

Since you have r-12. Use it! Don't cut corners as you WILL be working on it again if you do!
 

plaaya69

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#3
The r134a never cooled as good the r-12 the came in our old 87 Supra once it was converted over at the shop plus those fittings usually cause problems in the future with more places to leak freon from. I also remember hearing that the r-12 molecules are larger that the r134a so freon leaks do not develop as fast over time. There has been many others who would agree once they converted over to r134a that performance was not the best while some say they don't notice any difference. If I was to go r134a, a parallel a/c condenser would seem to help with a/c performance but those seem non existent anymore which is why I am sticking with r-12.

The mk3 Supra originally made for r-12 and was never designed for r134a, r-12 alternatives or a air duster cans but if there is better alternatives that work the same or better then I always like to hear the good's or bad"s on why to use it or not?
 

JDMMA70

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#4
Figgie is right. Every Supra ive converted, in fact every R12 car ive converted performed just as well sometimes better than the original system. Ive dealt with badly converted cars, most of that dealt with oil capacity, refrigerant capacity, air in the system, or faulty components. Also by the way ive done conversions on cars using the original condensers, a parallel flow condenser is a not a requirement, the air will blow just as cold.
 

figgie

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The r134a never cooled as good the r-12 the came in our old 87 Supra once it was converted over at the shop plus those fittings usually cause problems in the future with more places to leak freon from. I also remember hearing that the r-12 molecules are larger that the r134a so freon leaks do not develop as fast over time. There has been many others who would agree once they converted over to r134a that performance was not the best while some say they don't notice any difference. If I was to go r134a, a parallel a/c condenser would seem to help with a/c performance but those seem non existent anymore which is why I am sticking with r-12.

The mk3 Supra originally made for r-12 and was never designed for r134a, r-12 alternatives or a air duster cans but if there is better alternatives that work the same or better then I always like to hear the good's or bad"s on why to use it or not?

Not sure where you got your information.

Toyota own TSP (Technical service bulletin) has the information needed for r-12 to r-134a conversion.
The numerous times that I did r-12 to r-134a. I was able to match or exceed the 40 degree F at the center vents (best was 36 degrees, 4 degree but it gets painfully cold!).

All thanks to following the TSB down to the EXACT amount (it was like 200 grams of r-134a, but I am going off memory).

Please notice my wording, I did not say "about", "close", "guess", "estimate". I said "exactly" which means equals to the amount prescribed by the TSB. Deviate from that and well, that is a contributing factor in poor A/C performance. Of course lets not forget a proper vacuum pull to eliminate all moisture in the system (where most of the issues begin with).
 

Piratetip

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#6
Somehow my R-12 system has managed to stay charged for the entire length of my ownership.
Pretty amazing.
I should get an extra can of R-12 on hand just to top it off though, need to check the system pressures.
I am doubtful its fully charged, but still functions well and blows very cold air.

Bought the car in ~2002, have never had to add / recharge / purge / open any fittings, nothing.

Just stick with R-12 if you want to keep it.
Otherwise convert to R-134a.
 

3p141592654

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#7
Mine is on the same R12 charge since 1997 when I had the TXV valve replaced under a recall. That 22 years without servicing!! And I live in Cali so it gets used.

That said R152A is actually a great refrigerant and it has a 10x lower global warming factor than R134a. My only worry would be the purity of the stuff coming out of a duster can. Non-condensables in your A/C system will cause reliability issues long term.

To be specific, the COP is better than R12 and R134a and the pressure ratios are the same. Since R152a weighs 66.05 g/mol and R12 weighs 120.9 g/mol you need about 55% of a regular R12 fill.

R152aCOP.jpg

R152aPR.jpg


The source of that data is here: https://c.ymcdn.com/sites/psme.site...resentations/Engr._G._Catubao_PSME_NATCON.pdf
 
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figgie

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#8
Mine is on the same R12 charge since 1997 when I had the TXV valve replaced under a recall. That 22 years without servicing!! And I live in Cali so it gets used.

That said R152A is actually a great refrigerant and it has a 10x lower global warming factor than R134a. My only worry would be the purity of the stuff coming out of a duster can. Non-condensables in your A/C system will cause reliability issues long term.

To be specific, the COP is better than R12 and R134a and the pressure ratios are the same. Since R152a weighs 66.05 g/mol and R12 weighs 120.9 g/mol you need about 55% of a regular R12 fill.

The source of that data is here: https://c.ymcdn.com/sites/psme.site...resentations/Engr._G._Catubao_PSME_NATCON.pdf
Don't forget the other half!

R-152a is very flammable
 

Piratetip

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#9
R-152a is very flammable
FYI, some OEM's are moving to R-1234yf refrigerant now. (Tetrafluoropropene)
Also flammable.
I was working on an Alfa Romeo Gulia the other day and noticed a flammable warning label on the high side / low side connectors for the refrigerant system.

One downside for this stuff besides the mild flammibility bit is that its very expensive.
 

figgie

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FYI, some OEM's are moving to R-1234yf refrigerant now. (Tetrafluoropropene)
Also flammable.
I was working on an Alfa Romeo Gulia the other day and noticed a flammable warning label on the high side / low side connectors for the refrigerant system.

One downside for this stuff besides the mild flammibility bit is that its very expensive.
How much is the cost?

I am acquiring an 89 MKIII that has a none operational A/C. I can get r-134a in an shop around here. Can't source anything else.

Does it require differents superheat and super cool ranges?
Is it compatible with R-134a/R-12/R22 gauges?
Different oil than the Ester/Mineral/PAG of before?
 

Piratetip

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#11

figgie

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#12
Intresting read Piratetip.

Synopsis: HF-r1234yf will not be approved for retrofitting R-134a systems.

The service ports are totally different than r-134a (got to get new service port adapters).

Any r1234yf that has been contaminated cannot be reused.

Needed dedicated recovery equipment that prints out reports etc of the r1234yf recovery and recharge.

The biggest item I see different is that there is a tube (internal heat exchanger call IHX) that essentially allows some thermal efficiencies to be gained by running the r1234yf on the hot/ cold side together. I have seen this in the Water heaters for houses that essentially pump the exhaust through a pipe to assist in the heating of the water (using the very exhaust gases to help in keeping the water hot).

the pricing of R1234yf is still expensive.
 

3p141592654

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#13
Both R152a and R1234yf are classified as slightly flammable. You need it in the liquid state to get combustion and anything mixed with oil burns. So is R12 mixed with mineral oil by the way. Given R1234yf and R152a are EPA approved in autos, its clearly not a major concern some warning labels can't fix :) . The only real negative to R152a is the high discharge temperature, that might be a reliability issue. In a TXV system like the supra, the superheat will be fixed. The subcooling in auto applications tends to be a crapshoot.

1552431402478.png 1552431784533.png

R-152a
1,1-Difluoroethane known as R-152a or HFC-152a. Most people dont know that it is a common office product that we use almost every day and is commonly found under aerosol propellant. EPA has this as an acceptable replacement for R-134a. It is slightly flammable, non-ozone depleting (ODP), has a global warming potential (GWP) of 120.

R-1234yf (EPA choice replacement for R-134a, but is not a drop in).
2,3,3,3-Tetrafluoropropene commonly known as R-1234yf or HFO-1234yf a carbon dioxide, it is also a colorless gas and is a proposed replacements for R-134a in the automotive air conditioners. It was reported that tests by a European auto maker showed that the substance ignited into a ball of fire when researchers sprayed it and A/C compressor oil onto a car's hot engine. The product is classified slightly flammable by ASHRAE; several years of testing by SAE proved that the product could not be ignited under normal conditions experienced by a vehicle. R-1234yf has an Ozone Depleting Potential (ODP) of 0.0 and a Global Warming Potential (GWP) of 4

R-134a (Does not fall under the restriction of sale guidelines by EPA)
1,1,1,2-Tetrafluoroethane commonly known as R-134a or HFC-134a, It is also a colorless gas and typically sold under the name R-134a. In 1994 R-12 was phased out and R-134a became its substitute. R-134a is a haloalkane with thermodynamic properties similar to R-12. The phase out of R-134a began in 2011 in Europe with a total ban due by 2017. In the United States, there is a 2017 target date to replace the R134a Freon with a newer refrigerant. At this time R-134a has not been banned, but will be federally taxed so its price is forced up. The tax is intended to further discourage people from attempting to frivolously use R-134a such refilling a system with a leak and force them to repair the leak. R-134a has an Ozone Depleting Potential (ODP) of 0.0 and a Global Warming Potential (GWP) of 1400