OT - Air Conditioner - Alternative Refrigerant - HFC152a

Good day! I have made a couple videos of 2 expiriments I did with old car air conditioners. It is slightly off-topic because neither car is a TR. They are both GM cars with similar orifice tube / accumulator systems to the Regal.

I don't want this to get turned into a political debate or a safety debate. For some reason the topic of alterntive refrigerants usually goes that way. I don't want that. This is about the technical aspects of this particular refrigerant and the technical details of using it.

I don't have a FIRM opinon on it yet because the hottest part of the season has yet to come. In the 80's like it has been here, the HFC152a is completely adequate, but I'm interested to see how summertime goes.

The motivation behind these expiriments is the rising cost and impending phase-out of R134a. I want to find a lower-cost and/or non phase-out refrigerant gas that will work with our older cars, which is not extremely flammable. I don't care if it requires modifications, just so long as it can be done within the scope of a home shop.

I found a thread on another forum about the HFC152a refrigerant, which can be purchased for less than $4 per can, as DUSTER SPRAY at all the office stores and Wal-Mart stores. It seemed too good to be true, but the original guy is a respected forum member there, an engineer, and a certified A/C tech. So I gave it a shot.

The pressure curve for the HFC152a is very close to R12. The pressures are lower than R134a. The only down-side is, HFC152a is a light weight density compared to R12. Therefore it may take more volume flow through the system to get the same cooling. That's the part I want to verify during summertime!

The first video shows my first expiriment, with an 86 Buick Park Avenue coupe. It has a HR6 compressor and a cycling clutch / orifice tube system (CCOT) just like the Regal. The second one is another car with a V5 system. On that car, I also ecxplain the accumulator function.

Hope you guys enjoy this and it gives some ideas. I would like to hear if anyone has done similar conversions on their R4 compressor system.

One thing I always do if possible, on R134a conversions, is to replace the compressor pulley with a smaller pulley. This gives the compressor more shaft speed with the engine at idle. It helps keep the low side pressure down and the idle cooling ability up. I did change the pulley on the Park Avenue, however not on the Century. If I remember, the LC2 engine package has the smallest pulley available on the R4 compressor. That would mean you couldn't put a smaller-yet pulley on there. The second conversion (the Century) has vee-belts. It has the stock size pulley and it was working very very well. Once again, in mild weather.



Sincerely,
David
 

chopped39

Well-Known Member
I wonder how compatible it is with the oil in the system? It needs to mix with the oil. Thats were the lab tech has to step in and test it. you may be making a bomb if the fan stops and pressures get crazy. I'm cheap so I will go get some and charge my 96 century with it and see what happens. keep posting results.
 

Nick Micale

Tech Advisor
Staff member
Thanks for posting that info as we are again faced with yet another auto refrigerant for dubious reasons which we will never know?

In our area we take AC very seriously, especially if the wife's car is not cooling properly. :)

Since our summer temps have many weeks over 100 degrees, and lots extended days over 100 degrees, the Regals without R-12 are not "comfortable" with the less efficient refrigerants, and your forth coming info will be of great interest here.

It would also be helpful to know where you are located, and the ambient test conditions also especially with the different products.
 
I wonder how compatible it is with the oil in the system? It needs to mix with the oil. Thats were the lab tech has to step in and test it. you may be making a bomb if the fan stops and pressures get crazy. I'm cheap so I will go get some and charge my 96 century with it and see what happens. keep posting results.

Keep us posted on the Century!

Well, according to the research I have done (information online through 'informal' reading - in other words, I didn't save every link) it is mixable with the same oils as R134A.

The only way you could have any sort of explosion is, if the high-pressure switch failed. Back when I was a fulltime car mechanic, I received several cars with blocked orifice tubes or bad fans. The owner had bypassed the high pressure switch. Usually the first thing that happens is, the compressor clutch starts to burn up. If the clutch holds, the next is the releif valve opens and vents the refrigarant charge. There are several thigs that happen before a component would explode. It would be a high-side component, which are all underhood. There wouldn't be any release of refrierant in the car interior.


Thanks for posting that info as we are again faced with yet another auto refrigerant for dubious reasons which we will never know?

In our area we take AC very seriously, especially if the wife's car is not cooling properly. :)

Since our summer temps have many weeks over 100 degrees, and lots extended days over 100 degrees, the Regals without R-12 are not "comfortable" with the less efficient refrigerants, and your forth coming info will be of great interest here.

It would also be helpful to know where you are located, and the ambient test conditions also especially with the different products.

Hi Nick. I'm in central Alabama. This week has been mild, so as I mentioned - I don't consider this expiriment to be "well tested" yet. That day was in the 80's. I drove the Park Ave yesterday in same temps. When parked, I left the windows closed. The A/C brought the temperature down without any problems. But once again it was only 80 out.

You're in AZ so I'm sure A/C is serious business there!

Sincerely,
David
 

GNONYX

Well-Known Member
Hi David, Thanks for the informative video, I learn something new about Duster Spray known as HFC152a.
Please keeps us posted on more of your finding in the coming summer heat.
 

chopped39

Well-Known Member
I found this and its from 2003. It looks like they just don't like the flammability.
 

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Today was 85 degrees. I drove the Park Ave around all day in stop and go. It cools better than R134a. No change in compressor sound or other signs of system deterioration.

Thanks for the MACS report, that's good info. It looks like we've reached a point where no refrigerant will make everybody happy. Between cost/avilability, environment, and flammability - you can pick any 2 of the 3 but never all 3 in one gas.

Sincerely,
David
 
My 87 has the orignal R12 ac system. I used to have to add a bottle or 2 each season to have cold ac. Small leak I never found. I ran out of R12 3 years ago & was considering switching to R134a but now wonder if I could try HFC152a instead with no other conversions. Anyone think it's worth a try? Could I damage anything by just putting in a bottle or 2 & see if the compressor starts to cycle?
 
My 87 has the orignal R12 ac system. I used to have to add a bottle or 2 each season to have cold ac. Small leak I never found. I ran out of R12 3 years ago & was considering switching to R134a but now wonder if I could try HFC152a instead with no other conversions. Anyone think it's worth a try? Could I damage anything by just putting in a bottle or 2 & see if the compressor starts to cycle?

Hi, welcome to the forum! Unfortunately, no - you would be mixing incompatible refrigerant and compressor oil by charging in HFC152a into your system full of mineral oil. The result would be severe damage to the compressor after a few hours of operation.

You'll need to replace the system oil charge with Ester or PAG -based oil to use either HFC152a or R134a. Both of them use same synthetic oils.

If the system functioned with the R12, it would cycle and operate with any refrigerant; but the system would be wrecked by lack of effective lubrication.

When you open the lines to change the o-rings and fix the leak, it would be a good time to perform a system flush and replace the oil.

Sincerely,
David
 

87GN_70GS

Active Member
Right before the ban, I walked out of my local auto parts store with a case of R-12 cans. Paid 99 cents per can. I still have 11 cans. Havent decided if that's what I will use on my 70
 

chopped39

Well-Known Member
I know there was a pulsing orifice that was developed by glenview radiator in Il back when 134 came out that pulses the refrigerant instead of a steady flow and it will cool just as good as r12. I never used one but was told they worked. I will try this and the 154a in my Buick when ready
 

SuperSix

Flaccid Member
Hello!

I learned about this by reading a thread posted here: http://www.ihadav8.com/forum/index.php?topic=3983 (crossposted) and it got me thinking about this conversion.

I decided to try it on the 87T. I had rebuilt the A/C 4-5 years ago, but it stopped blowing cold, I still had R12 in the system. It hadn't worked in ~3 years, but still had a bit of pressure. That's a good sign.

I purchased:
ACDelco 15-50120 Orifice Assembly
ACDelco 15-1681 Accumulator Dryer (This is the correct TR part #, despite what Amazon and RockAuto say)
Four Seasons 26777 Cap & Valve Air Conditioning System Seal Kit
This includes new valve cores for the system, and some spare caps. After much Googling and reading, supposedly a large amount of A/C leaks are from these. From the looks of the old ones, they may have been factory. All were replaced.
New Orings (I already have a shit ton of them, and a lot of the old ones were ripped/too big - lesson learned)
8oz PAG150 oil (Old compressor - wanted higher viscosity oil)
1/2 gallon A/C flush (used 80% of it)
4 cans 10oz office duster, Big Lots, $4 ea (only used 3) (They had R134 there for $6.75/can - with R134 being phased out, I am considering a bit of a stockpile)
New compressor seals - Got the wrong ones, another error from Amazon and Rock. Turned out to be simple orings I already had.

I went all out I guess. I pulled the evaporator out (That's another issue I read about - old evaps that get corroded/clogged, etc, especially pre-cabin air filter cars) and soaked it in a bath of home A/C coil cleaner. I gently brushed it, and cleaned it, used plenty of water. It didn't look TOO bad to begin with, but I swear I can feel more air volume in the cabin.

I did snap the evap cover when I was trying to remove it, this is the first time I have taken one apart. instead of Googling how to remove it, I went all cowboy on it. nothing a little silicone won't fix, and hey - it's gonna be my son's car soon. :p

I was not impressed with the amount of debris behind the wide trim strip and other parts I removed - spent a little while cleaning that up. I scavenged and reformed the black sealing goo and reinstalled it. I think I only stripped two screws - that's a win for me.
I pulled everything out, flushed it all (Except compressor) I pulled the compressor out and drained what oil out of it I could. I put a bit of the new oil in and rotated it a few times (Thanks CharlieF!). I think this is the factory compressor, and has never been out of the car. I'm not sure. Either way, it's working. I ended up getting flush all over the left side of the engine - gave me a reason to clean up the motor a bit.

I installed all new orings, new orifice tube (old one pictured below), new accumulator and all new valve cores. Reinstalled it all, then realized I had forgotten to add oil. It was really late, I was beat - but I had to get the system buttoned up so I could put it on vacuum. As fast as I could, I put 2oz in the condenser, and the remaining ~4-5oz in the accumulator. I then put it on a vacuum for ~2 hours while I cleaned up, etc. and then left it for the night.
The next morning, I went and checked, no leaks. For giggles I turned the vacuum pump back on, it may have run for ~2 more hours.

I had a hard time figuring out the correct charge for this freon, I couldn't find a reference to that anywhere.

So, here's what I came up with, am I right?
Factory Charge: 3.25 lbs R12
HC152A molecular weight - 68g/mol
R12 molecular weight - 120g/mol

68/120 = .56

3.25lb * 16oz - 52oz factory R12 fill, or 29.12oz of HC152A/R152 (52oz * .56)

I was using 10oz cans, so - three cans should be a fill? Assuming ~1-2oz loss overall while adding freon.
When I took it for a ride yesterday with ~22.5oz - the center outlet temp got down to 51f. Ambient was ~80f, humidity was ~60%.
Idle, it will get down to ~55f. After reviewing my math above a bit more, I added ~5 more oz this morning.

Also - before I added anything this morning, the resting PSI is 85.5, and yesterday, I couldn't nook up my high side port, an oring popped loose in the connector. Then I realized this morning I could just remove the R134 fitting, and use my R12 high side hose.

Here's better the running pressures from this morning, AFTER adding a total of ~26.5oz (Estimate)
Low side - 37PSI
High Side 190PSI
Center outlet temp was 54, this is at idle.

I await the lambasting for something incredibly simple that I fucked up. :rofl:

Some interesting links:
http://www.rx7club.com/1st-gen-arch...ap-safe-alternative-refrigerant-997918/page4/
http://www.s10forum.com/forum/f135/how-to-r152a-conversion-493953/
http://www.sae.org/events/aars/presentations/2008/manhoekim.pdf

Pics!
P1000249.jpg


P1000250.jpg


P1000251.jpg


P1000252.jpg


Old orifice tube. Doesn't look TOO bad to me - experts?
P1000253.jpg


Suckin!
P1000256.jpg


P1000257.jpg


The bad part is I found out the driver's side upper control arm bushings are completely shot - it explains the random clunking. I think I will wait for the son to come home on leave - he needs to learn how to rebuild a TR front end. :p

Kinda hard to see in this pic, but they are the worst I have seen. Oddly, the passenger side bushings look tired, but they aren't disintegrated like the driver's side.
P1000260.jpg
 

SuperSix

Flaccid Member
Daveismissing from my board just posted this - good news!

http://www.gpo.gov/fdsys/pkg/FR-2008-06-12/pdf/E8-13086.pdf

SUPPLEMENTARY INFORMATION: This final action provides motor vehicle manufacturers and their suppliers an
additional refrigerant option for motor vehicle air conditioning systems. The refrigerant substitute discussed in this
action (i.e., R–152a) is non ozone depleting. Members of the MVAC manufacturing and MVAC service industries have all been actively
engaged in the development of this rulemaking and are developing prototype systems with the use conditions defined in this rulemaking.
This final action helps harmonize U.S. MVAC alternatives with European Union (EU) MVAC alternatives. The EU has banned the use of R–134a, the
predominant MVAC refrigerant in the U.S and the EU, in new cars beginning in 2011. By 2020, cars sold in the EU may have to include the new alternative
in this action. In response, U.S. original equipment manufacturers are developing MVAC systems using R– 152a and other alternative refrigerants
for the European market and for possible U.S. sale as well. EPA is deferring final rulemaking on R–744 (carbon dioxide). EPA is currently continuing to consider further
several issues with this regulatory action.

More info from SAE/Delphi
http://am.delphi.com/pdf/techpapers/1999-01-0874.PDF
 

SuperSix

Flaccid Member
Another successful HC152A conversion - the wife's '96 Integra.

Last year, I replaced most of the A/C. Ever since then the performance has been OK, not great, and the hotter it gets, the worse it seems to be. So, while she doesn't ask for much, she asked I check it out. There has also, since my rebuild, another issue that drives her crazy - a whistle from the evaporator, or possibly the expansion valve. The expansion valve is one thing I should have replaced, but didn't.

I thought that the whistle may be the expansion valve.. I think I saw a reference or two online to that.

I bought a new valve, and planned on putting it in today. I decided the recover the system, vacuum it down, and refill it with HC152A. Then see, once other variables were eliminated (freon level, water/air in system, etc) if it still whistled, possibly saving the bullshit task of removing the evap under the dash, and replacing the exp valve. I also changed the high side Schrader valve, I only had one replacement though. Pulled and lubricated the low side one for good measure.

I used a hillbilly tactic to measure the oil that came out when I "recovered" the R134A that was in the system. I caught it in a clean catch jar - and used a digital scale to see how much oil I needed to add back in. After realizing I didn't HAVE anymore PAG100 (Or any PAG, for that matter), I poured back in what I caught in above mentioned catch jar.

Pulled a vacuum on it for ~2 hours, The R134A/HC152A ratio is .64. Factory fill is ~23oz, 23 * .64 = 14.72oz HC152A.

I put in one 10oz can, and the center outlet was down to 48f, ~85 ambient, ~50% humidity. All at idle.

I stopped there, 48f is pretty damn good - not sure I wanna fuck with it.

So - it cost me $2.67 to refill the A/C. ($8/3pk 10oz cans)
 

SuperSix

Flaccid Member
Whoa..

HC152A (Office dusters "canned air") is:

  • Better for the environment, doesn't deplete or damage the ozone layer.
  • Lighter molecular weight means less is needed (.64 ratio) Average Honda R134A charge - ~23oz, equivalent HC152A charge - ~15.4oz
  • Much cheaper (HC152A ~$4/can, R134A - ~$13/can, non sale prices)
  • Completely compatible with existing R134A (and properly converted R12) lubricants and systems
  • Performance exceeds R134A in many scenarios in most systems
  • Rumor has it that R134A is getting phased out in the next 1-2 years, I assume the cost of R134A will jump

So why aren't the auto manufacturers using it?

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

Quote
FACT SHEET: Substitute Listing in the Motor Vehicle Air Conditioning Sector

Action

EPA is listing R-152a as an acceptable alternative with use conditions for motor vehicle air conditioning systems.
This final rule allows the use of a new alternative to ozone depleting substances in the motor vehicle air conditioning sector and outline the conditions necessary for its safe use. The substitute is a non ozone-depleting gas and consequently does not contribute to stratospheric ozone depletion.
This new alternative, when used with proper risk mitigation technologies, would reduce the impact of mobile air conditioners on the environment.

Background

Under the Significant New Alternatives Policy (SNAP) program (Section 612 of the Clean Air Act), EPA reviews alternatives to Class I and Class II ozone depleting substances (ODS) and approves use of alternatives which reduce the overall risk to public health and the environment.
Since 1994, the SNAP program has reviewed approximately 400 alternatives across the industrial, consumer, and military sectors.
The European Union has proposed and is expected to ban the use of HFC-134a and other fluorinated gases in a variety of applications. By the end of the decade, car manufacturers in the European market may have to move to this new alternative. In response, U.S. car manufacturers are developing systems using this new alternative refrigerant as well.
If auto manufacturers chose to adopt this technology, they would be required to install safety devices to mitigate risks of fire or over-exposure to the refrigerant in the event of an accidental release during servicing or vehicle operation.
 

SuperSix

Flaccid Member
Some new A/C lessons I learned from this:

Replace Schrader valves and HI/LO port caps (cheap insurance)
Vacuum, vacuum, vacuum
Make sure to purge manifold lines, ANY 'air' is bad.
Don't use oversize orings because you think they will seal better.
 

Jack Parl

Member
I'llhaveaV/6
The EPA should stick to reducing alleged problem ( R12 depletes ozone layer) Rather than dictating a one size fits most . 154???) They key for any system is quality components checked regularly to prevent leaks.I live in the Washington Metro area. I assure you the EPA consists of pencil necked geeks driving a Prius.Doubt if half of them could open the hood. I had to say it ! Now on my way to Staples for case of dust off. Great Info!
 
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