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1966 Olds Toronado A/C

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  • #16
    I think the "powers that be" 1st made it a hard rule that auto A/C can't use flammable (class B) refrigerants. Then they wanted non ozone attacking, now they want non climate warming.
    The problem is: those three requirements are mutually exclusive. Any two may be but all three no. They have now started backing away from the non flammable and saying low flammable is ok. That opens the door to things that were verboten only a few years ago. I think 134a is slightly less flammable than 152a, but both support combustion to some degree.
    To get around their own rules they have made a new class of "slightly flammable" that can be used.
    When the choice came to pick between 134a and 152a the difference in flammability and the fact both required different oil, 134a won that battle. It does seam like 152a would be better in retrofits, but I'm not sure. Certainly there is something to be said for "going with the crowd" in terms of availability.

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    • #17
      I know this is an older thread, but I came across this statement while looking up other stuff and it applies to this refrigerant:
      HFC-152a is an A2 flammable refrigerant as classified by ASHRAE 34 and should be used only with a secondary loop application. However, until MAC systems are developed to use HFC-152a (R-152a), no SAE Standards for system design, service equipment or service procedures have been established. The R-152a service fittings described within this Standard were established as part of the industry’s evaluation of replacement refrigerants and are maintained for future design guidance and to prevent potential refrigerant cross contamination

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      • #18
        Sorry guys, I didn't realize there had been more replies. I didn't mean to be rude.

        I charged the system with R134A (by weight equivalent from R12) and it worked acceptably, although cooling really suffers when the car is at a stop (there is a large gap between radiator and condenser, with nothing to prevent air from the mechanical fan going around the condenser), so this lack of air flow through the condenser will need to be addressed.

        Ambient temperatures have dropped, so this will have to wait until next year, but I still haven't given up on R152A. After I address my airflow problem, I'll lower the POA setpoint to 23PSI and report back with my results.

        Thank you all who responded and my apologies for not following up.
        Last edited by Mikel; 4 weeks ago.

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        • #19
          When charging by weight, 134a should be 75%-80% of the R12 weight, so you may be a little overcharged. Also 134A also required a lower POA valve setting, around 26 psi IIRC.

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          • #20
            Mikel - late myself as the site doesn't send a notice. By weight Cornbinder is right. Sorry if already said or asked but if this has a sight glass at least take a look but isn't considered reliable like when OE new. These held a pound too much no problem (some) as if expecting some leakage as normal.
            Don't forget there's always a good clue by "touch-feel" lines for temps in and out of evaporator, look for wet, not frosted return lines and that it makes condensate (water) if any humidity it's working about as well as it will IMO.

            Other: For acquiring 134a now check out the home centers for now outdated 12oz pierce only cans just seen here for under $6 vs double that. Give it up to loss if you use part of one doubt you can save partial use of one (either type of tap) lose it on me. Interdynamics (others) made brass taps with caps intended to save indefinitely help but no guarantee they'll work. LOOK FOR THOSE USED if you want to have plenty on hand ones I have, have "O" rings and wadding give you a chance anyway,
            Tom
            MetroWest, Boston

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            • #21
              Thank you guys.

              I do have a sight glass in the dryer, but unfortunately it is buried out of sight behind the grille of the car (so much for serviceability).

              My POA is set at around 32 PSI, so I suppose I could make that adjustment fairly easily. I did check it with compressed air before I put together the system. The problem is that temperatures now are in the mid 70s, so even my mediocre-performing A/C feels super cold.

              I really would like to set the POA to 23 PSI and give R152A another try.

              I will keep an eye on the weather forecast. If we have any hot days left this year, I may be doing some experimenting!

              Thank you.
              Last edited by Mikel; 4 weeks ago.

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              • #22
                Ambient temps? It's a problem to KNOW for sure pressures and performance is right I'll say if lower than REAL 80-90F, that being the air thru the grille. Take into account surface you probably are on is colder now also a running car is getting that at it vs stuck in traffic on a no shade road.

                This stops me for performance or really tweaking a system especially a retrofit. Another identical one may not be the same never mind fully an antique car.

                So I suggest get close so oil moves and you feel high side heat and low side cool perhaps even sweating?

                I don't wish to do it again but heated my shop (took all day) to 100F, wait for tools (lots of course) to also warm up do do a car that had an accident HERE was headed back to FL to 80s-90s the condenser new from collision so empty. Got it but not worth the cost to heat that hot in a shop I did just want to see if I could. Storage of R-134a also a consideration if too cold it won't dispense out on its own. Was hovering ZERO that day and windy.

                Had to say that it was fun to succeed but you have the issue just try to stay on lower guess side if used as more cold comes I think even 1966 would kick on A/C for defrost setting to exercise it if on seconds. If not circulating oil it's killing itself you don't need that.

                Subject to opinions and reasons + types of vehicles. I disable my compressors for Winter (too many vehicles) so they (old too) don't all need new compressors or more in Spring. So far so good all are OE original systems. Do not do that to electric fanned vehicles that are computer controlled turn on both by high pressure or hot enough engine coolant return can mess those up,
                Tom
                MetroWest, Boston

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                • #23
                  Hopefully weather will cooperate in the next few weeks

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                  • #24
                    Same here, rain and cool for a while. Was thinking about the sight glass. If you had or wanted to use one of those scopes, bendy line fits in spark plug holes shows on screen on device or real good ones records it. Harbor Freight has them if close by. It's not supposed to be useful for retrofits but interesting and was close for some I did from the 60s very small glass on some. If you do remember to raise idle up may be able to move "step cam" for cold idle on most carbs with automatic chokes I think this must have.
                    It's a side idea I do recall most raced high RPM with a touch of gas pedal or pull on rod/cable watch it trip choke. See the thing "the step cam" GM/Rochester Quadrajets or some other (Olds would play with others or changed out long ago all "Quads" were fussy to adjust or some said Spring and Fall turn choke heater a notch or two. Laugh, each so unique the owner knew how many pumps stone cold or not to if already warm perfectly if paying attention. No two alike exactly.

                    So hope for a warm to hot stretch it's still possible?
                    Tom
                    MetroWest, Boston

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                    • #25
                      I readjusted the POA today to 23 PSI. Will be trying R152A this weekend. Let's hope for some warm weather!

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                      • #26
                        ,Just watch center vent temps , subtract ~5F for what evap really is AND that it drips water. If not, that's too low. Hard to be sure this time of year of course,
                        Last edited by Tom Greenleaf; 2 weeks ago.
                        Tom
                        MetroWest, Boston

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                        • #27
                          That is the beauty of devices that control the evaporator temp by controlling the pressure, the refrigerant will not get colder than the boiling temp of the pressure selected. Unlike a frost switch, that can be "fooled" by how it is placed and where, if the refrigerant can't drop below a set boiling temp, neither will the evaporator fins.
                          The drawback is: every refrigerant has a different boiling pressure at 32 degs, so every change in refrigerant requires a different setting on the pressure regulation device.
                          The same system is used in commercial refrigeration when you have two evaporators that cool to different temps, like a refrigerator and a freezer, run on the same compressor and condenser. You use a thermostatic switch for the colder temp evaporator and a pressure regulator for the warmer one.
                          It is also good on engine driven devices when you don't want to clutch under load, the compressor runs continuous, but the evaporator never drops below the setpoint. Auto A/C started getting away from it when fuel economy became more important than A/C component life in the 70's.

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                          • #28
                            Good morning.
                            I charged approximately 30oz of R152A and I get 42 deg vent air at HIGH fan speed. Pressures are 23-24 PSI low, 160 PSI high. 65 deg ambient temp.

                            Tomorrow supposedly we will be in the upper 70s. Will get more measurements and see if it's dripping water.

                            Thank you.
                            Last edited by Mikel; 2 weeks ago.

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                            • #29
                              Bit cool out but that's impressive still. Keep an eye on it for REAL air temps, right where you are as it comes in thru grille. Dripping to me just proves it's not freezing up anywhere also depends on dew point/humidity of the day or area you're working. Already said if 30oz checks out for assorted conditions definitely mark that down under the hood,
                              Tom
                              MetroWest, Boston

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                              • #30
                                Originally posted by Mikel View Post
                                Good morning.
                                I charged approximately 30oz of R152A and I get 42 deg vent air at HIGH fan speed. Pressures are 23-24 PSI low, 160 PSI high. 65 deg ambient temp.

                                Tomorrow supposedly we will be in the upper 70s. Will get more measurements and see if it's dripping water.

                                Thank you.
                                30 oz sounds like a lot. I thought I read somewhere that like 134a when you change to 152a from R12 it takes less by weight. I can't find where I saw that, but you might want to double check the amount needed. Might take a little trial and error to get it dialed in.

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