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Messing around with Red Tek r12a A/C recharge - not getting anywhere

Discussion in 'LH: Large Cars, 1993-2004' started by MoPar~Man, Jun 20, 2015.

  1. MoPar~Man

    MoPar~Man Active Member

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    To recap: Condenser coil on my '00 300m was punctured back in early February. Ok - didn't needed it for the next few months. About a month ago I replaced it (Rock Auto). Replacement fit nice, came with seals blocking the 2 ports. Removed the seals and heard hiss of air - either it was pressurized or vacuum-ized at the factory. Either way, I guess that means it has no leaks. Original line fittings were clean and the seals looked good.

    Today I'm messing around with "Red Tek" r12a recharge kit. The high and low ports on this car seem to be mounted directly to the compressor - not in-line on the hoses that a lot of youtube video's show. If there's only supposed to be one port with a plastic "H" screw-cap, and one port with a plastic "L" screw cap on this car, then they're mounted directly on the AC compressor. And you have to take the oil dipstick out because the handle is in the way of the Low port.

    So I follow the directions and screw a bottle of r12A to one end of the line that comes with the kit. There is a pressure guage on the line, and a slip-ring fitting on the other end that connects to the Low port. Connect the line to the Low port - it reads zero. The High port has a slightly different fitting - so I can't measure it using this guage.

    I turn the can upside down, screw in the point that pierces the foil seal, and I hear something flowing. I have to be careful that the slip-ring fitting stays plumb on the Low port because and rocking or angling of the fitting breaks the seal and I hear a leak at the port. Why can't they design these better?

    The pressure quickly climbs to 80 (PSI I guess - according to the printing on the guage). Here's a closeup pic of the guage:

    http://www.gmforum.com/attachments/...dtek-ac-equivelent-2lbs-r134-qty-img_3670.jpg

    It didn't feel like the can was empty, but no more of it was flowing into the compressor. BTW, the engine wasn't running while I was doing this.

    I screwed the needle valve on the can closed and removed the line from the Low port. Then started the engine, then turned on the AC. Got nothing but warm air. The AC was on - was making a bit of noise. Ran for about 30 seconds and turned off engine. Reconnected the line to the Low port - pressure was maybe 70, opened needle valve to let more in, pressure went up to 90 quickly. Started car again, still no cold air. At this point I'm thinking maybe this pressure is too high. I stick a pointy tool into the high-side valve and yes - lots of pressure there.

    I mess around letting some gas out of both low and high ports and get to a point where I let out all pressure from High side and bring the low side to about 30 (psi?). Start the car, get maybe some cooler air, but not worthy of a working A/C system. I notice (with the engine not running) that letting gas out of the high side does reduce the pressure on the low side - don't know if there's supposed to be an air-tight seal inside the compressor between the high and low side or not.

    I don't get why, with a system that clearly was equalized to ambient pressure before it was sealed by installing the new condenser, why it would take less than half a can of this stuff to bring the low side to a pressure like 80 (with the engine not running), and why (after starting) the pressure didn't immediately fall to allow more of this r12A to be injected. I should have needed 2 of these cans to bring me to the equivalent of what I had with 134a.
     
  2. MoPar~Man

    MoPar~Man Active Member

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    Ok. I think the issue is that when the ports are on the compressor, you have to add this stuff while the engine is running and the AC is on. There isin't enough space to add the stuff when the Low port is not connected to a line with space inside it. I've added the entire second can while the engine was running and I do indeed have cold-blowing air now. The low-side pressure does read about 35 lbs while running, and 70 lbs when the engine is off.
     
  3. Bob Lincoln

    Bob Lincoln "CHECK FAULT CODES"
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    As was discussed at length on the other thread, you will continue to get warm air with this flawed method. As I said at least twice before, you MUST draw a vacuum before recharging any A/C system. Either do it right or don't do it at all, but don't expect decent results when you do it wrong.
     
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  4. GLHS60

    GLHS60 Well-Known Member

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    Either Bob or I misread your post, as I see you got cold air after following the instructions.

    Start engine, set A/C to max, install Red Tek.

    Thanks
    Randy
     
  5. Bob Lincoln

    Bob Lincoln "CHECK FAULT CODES"
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    I did miss his last post when I posted.
    My previous comments about this technique stand. The system is now contaminated, and without drawing a vacuum, it is destined to fail much earlier than it would have otherwise.
     
  6. GLHS60

    GLHS60 Well-Known Member

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    I was responding to your statement that "he will continue to get warm air".
    He stated he got cold air after starting the engine.
    I use Red Tek in my own vehicles, and have had no problems over many years.
    You have great A/C theory but no experience with Red Tek.

    Thanks
    Randy
     
  7. Bob Lincoln

    Bob Lincoln "CHECK FAULT CODES"
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    I have a lot of experience with both R12 and R134a systems, and conversions. All have been successful. I have no experience with Red Tek, nor with the Interdynamics Death Kit, because they are inappropriate ways to service A/C, and I choose to fix A/C the way it's supposed to be done and have it last, not take a cheap shortcut method that will cut its life and make it too expensive to fix when it self-destructs.
     
  8. MoPar~Man

    MoPar~Man Active Member

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    I was under the impression that given an air-filled system sitting at zero internal pressure, that connecting the Red Tek can to the Low port without the engine running was sufficient to at least dump the contents of the can into the system without needing to actually be running the compressor. That might indeed be the case where the Low port is located on a hose somewhere distant from the compressor (as all the video's I've seen). But on my 300m, the Low and High ports are located directly on the compressor, and as such that probably does necessitate running the compressor during the initial zero-state charge.

    Either that, or dumping my first can into the system (and subsequent cycles of running the compressor and letting the charge out) has purged some or most of the ambient air that was initially in the system, and the second can has brought the system up to some level of refrigerant that is enabling satisfactory cooling.

    I've just returned after a 4-hour highway drive with the car today, using the A/C intermittently, and it is indeed working very well every time. I intend to check the oil concentration using the small gizmo provided in the Red Tek kit, and beyond that there isin't much that needs doing beyond measuring the low pressure side with the compressor running to see if I need to add more r12a. I would like to measure the high-side pressure, but I'd need an adapter converter for that (maybe Princess Auto or Canadian Tire has a suitable kludge).
     
  9. GLHS60

    GLHS60 Well-Known Member

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    I'm glad you finally have cold air !!
    Its nice to find an inexpensive, user friendly and environmentally safe product that works so well.
    Enables people to drive older vehicles with working A/C that otherwise might not be cost effective.

    Thanks
    Randy
     
  10. manybrews

    manybrews Well-Known Member

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    Okay, this is an old post but worth an update.
    RedTek is R12a, not R12.
    it will require only about 35% of the same charge as R12 to get the same (or most likely better) results.

    BUT, its an HC refrigerant. It does not like to be added in a vacuum. HC refrigerants work better with a small amount of moisture in the system, and it will not corrode because its not a fluorocarbon.

    An HC refrigerant will work with any type of oil from either R12 or R-134 systems.
    It will have lower high side pressure.
    It will have improved condensing, and should work better than both r12 and r134 refrigerant for a given temperature.

    You do not treat an HC refrigerant exactly like a CFC refrigerant.
    It is technically flammable, but you're talking about probably 10 ounces maximum. Technically ALL refrigerants are flammable when they are mixed with the oils in the system, so its a moot point at best.

    It is legal to use them in America, but technically you cant retrofit a R12 system to R12a. You first have to go to 134.
    (silly loophole, but worth noting).

    HC refrigerants are used worldwide and work extremely well.
     
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  11. AllanC

    AllanC Well-Known Member

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    I must disagree with this statement. Please quote the reference source that indicates no need to pull a vacuum on an air conditioning system when charging with a hydrocarbon refrigerant or moisture in the system enhances performance.
     
  12. manybrews

    manybrews Well-Known Member

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    Red tek LITERALLY tells you on their own website to NOT pull a vacuum when charging. Charge at “0” atmosphere. See below.

    But you also misunderstand I think. Or perhaps I didn’t explain quite well enough.
    A vacuum should be pulled to test for leaks. And remove the majority of the moisture.
    But it should then have the vacuum removed and be charged at a neutral atmosphere condition. And any moisture that is in the atmosphere at that time can enter the system. And HC systems perform a bit better with this moisture.
    The system should not be saturated with moisture, but HC refrigerants do not absorb moisture so it’s presence it not harmful and will not cause corrosion.
    Moisture in a R-134 system will destroy it quickly. It will convert into hydrochloric and hydrofluoric acids. That will not occur with HC refrigerants.
    Moisture free refrigerant systems are almost impossible to achieve. HC refrigerants are not affected and in fact will benefit slightly from this inclusion.


    You will have a difficult time finding anyone with this information because the chances of you finding anyone with HC refrigerants experience on autos is almost nil. It just doesn’t exist in America.
    But I’m telling you that HC refrigerants are beneficial in every way, and absolutely crush r134a for performance, reliability, and enviromental benefits.

    I’ve used red tek. It is a fantastic product.
    The lobbyists for DuPont are the reason it’s not used in car, NOT because it’s a bad refrigerant.
    Replacing the 134 in my Mitsubishi Eclipse increased its performance dramatically, whilst at the same time decreasing load on the system. And the 134 system was/is in perfect working condition and fully charged. It’s just that much better.

    The myths out there about HC refrigerants are all just that. Myths.
     

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    #12 manybrews, Jun 8, 2019
    Last edited: Jun 8, 2019
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  13. AllanC

    AllanC Well-Known Member

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    I reviewed charging instructions that Red Tek has printed at its website. As mentioned you evacuate the system to 0 atmosphere / zero gauge pressure. The system is EMPTY and has no fluid gas inside it. You do not want non-condensable gases such as nitrogen in the system. Procedures indicate to NOT draw a deep vacuum and that is puzzling. One would like to quiz the scientific reason for not pulling a deep vacuum. And instructions indicate moisture is not an issue.

    If you inadvertently pulled a deep vacuum I would assume that the proper procedure would be to allow atmosphere to enter the system to attain a slight positive system pressure. Then you would evacuate to 0 atmosphere and stop. System is void of any gas inside of it.

    The H C refrigerants will not react under heat and pressure and moisture as CFC and HFC refrigerants do to form acids. So that is good. Moisture enhances the refrigerant process is interesting. Have to keep searching to find a scientific reason for this phenomena.

    I do believe the hype about H C refrigerants and explosive potential is somewhat over played. Any refrigerant mixed with oil and vaporized in an escaping, high velocity vapor stream will be ignitable due just to the oil content. And how many explosive devices exist on cars today "to protect us from ourselves"??? Air bags all around and a 20+ gallon liquid bomb (fuel tank) potential under the rear floor.

    Starting in model year 2021 new vehicle air conditioning systems in the United States will be equipped with R1234yf refrigerant. It has lower GWP (global warming potential) than other refrigerants. But it is somewhat explosive and could be ignited in a fire. So the auto industry will be supplying more robustly designed and constructed evaporators to reduce potential leaks in the interior cabin of the vehicle. So is the industry slowly moving forward and saying that combustible refrigerants are acceptable if managed properly and help offset negatives of other so called safe refrigerants?

    Nothing wrong with learning and reviewing alternative view points. Informative discussion.
     
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  14. manybrews

    manybrews Well-Known Member

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    Yes, this is the exact issue that DuPont used to make R-134a the refrigerant of choice when the switch was done.
    It was lobbied for and hyped to lock in business for them, and that's the reason its used.
    R-134 is a cheap hydro-fluorocarbon. It is cheap to make, is plentiful and works. But there are SO many better choices.

    The Redtek R12 is flammable, but auto ignition doesn't occur until 1500 degrees! Although it would ignite with fire/spark.
    R-134a is not technically flammable, but will burn when under pressure and when mixed with oil (as it is in our cars). If it burns, it creates phosgene gas and will kill you pretty much instantly (notice that that wasnt a selling point of DuPont).

    People don't seem to worry about the 150 pounds of highly volatile fuel rolling around right behind them, but panic about 6-10 ounces of an HC refrigerant in their air conditioners!

    And you are correct, the r-1234 refrigerant is technically flammable. The automakers were worried about it and originally were planning on using "dump" valves that would evacuate the system in a wreck, but have since decided that its not enough to worry about. And its not.

    You will likely not find one case of a fire due to HC refrigerant use in an auto worldwide.

    I wish there was more CORRECT information out there about this topic, but the BS lobbying done 25 years ago did its damage and convinced everyone about the horrors of HC refrigerants.

    The biggest problem with them is that they often work TOO well. On a vehicle that doesnt use temperature regulation of the evaporator, freeze up will likely occur.
    Fortunately, most modern cars due use temperature regulation vs pressure regulation.
     
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  15. AllanC

    AllanC Well-Known Member

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    My wife and I had a friend in DuPont management that had a strong background in chemistry. This information is based on discussions we had at the time with her and Dupont's role in developing a chlorine free automotive refrigerant. In the 1986 - 1990 time frame DuPont made various replacement refrigerants for R12. There was no one refrigerant that was chlorine free, had similar heat capacity characteristics as R12 and similar evaporation and condensing pressure temperature relationships. So DuPont made many replacement refrigerant samples and supplied the technical physical property data associated with each refrigerant. This was given to the automotive industry and the industry made the determination of which refrigerant to use.

    At the time extended warranties were starting to be offered by the manufacturers on vehicles. The manufacturers had concerns that if R12 became non-existant and there was an extended warranty issue with the vehicle air conditioning system, expensive retrofit of compressors, condensors, evaporators, etc. would be required if R12 was no longer available. So the industry chose R134a as the replacement refrigerant because it was closest in physical properties in relation to the evaporation temperature pressure relationship as compared to R12 refrigerant.

    So the comment that DuPont had undue influence on the selection of R134a as a replacement refrigerant is not entirely true. And manufacturing a new refrigerant in an efficient, timely and low cost manner can be a challenge. When R134a first was developed it was relatively expensive but over time as more chemical plants came online to produce the refrigerant, economies of scale developed and the unit cost of R134a refrigerant dropped.

    The same scenario is occurring with the R1234yf refrigerant. Demand is low now as the auto industry has not fully committed to its usage until model year 2021. As I understand it Honeywell has the only chemical facilities making this refrigerant. So it is currently very expensive at $60.00 - $70.00 per pound. As demand increases and more manufacturing plant capacity comes online to meet the demand, hopefully the price will drop substantially.


    Evaporator freeze up when using an alternative refrigerant is due more to design parameters and less with temperature regulation of the evaporator. Many automotive air conditioning systems use a fixed orifice metering tube. If you change refrigerants then the orifice metering tube should be changed accordingly. But how many folks will do that or even know that should be done?
     
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  16. manybrews

    manybrews Well-Known Member

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    Quite true. But even orifice tube systems often use thermostatic cycling to prevent evaporator ice-up. Some use pressure cycling, but that is where the problem can occur.. the HC refrigerants work at roughly the same pressures but have noticeably better cooling, so the evaporator is very prone to freezing.
    In my own car (Mitsubishi Eclipse), it uses an expansion valve metering and thermostatically controlled clutch operation, so it still will continue to operate without the freezing issue.
    With the HC refrigerant, the system is "off" roughly 30% more frequently than it was with r-134a refrigerant. Freeze up would almost assuredly occur if not for the temperature sensing of the evaporator.

    Most modern AC systems use some type of evaporator temperature sensing to prevent freezing, but not all.
     
  17. Tomguy

    Tomguy Well-Known Member

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    So I don't see this quesiton having been asked anywhere:
    Why are you using RedTek R12a on a system originally filled with, and designed for, R134a?
    Are you intentionally trying to ruin your 300M's A/C system?
     
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  18. manybrews

    manybrews Well-Known Member

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    H
    Not sure why you’re asking this question when the answer has been given.

    I’m also curious why or how you think using an alternative refrigerant “ruining” the ac system?
    Do you ruin your car using an alternative oil from the original spec?

    But, I will give you many reasons.

    HC refrigerant is inexpensive.
    HC refrigerant will noticeably improve the output whilst at the same time extend the life of the system.
    It will use less energy thereby increasing power and mileage.
    It is far less harmful to the environment.
    Depending on your country, you may not be able to purchase r134 refrigerant.
    HC refrigerants are far and away the most efficient refrigerants on earth. The conversion to them is in effect worldwide, just not yet in autos. Although it is estimated that Australia has about 8% of their cars running it.
    They are fully compatible with any and all currently used refrigeration oils.
    HC refrigerants do NOT turn into acid when in the presence of moisture as does r134, which will again increase the life of the system.
    They do not require any type of modification to use if retrofitting from R12 (although that’s obviously not the case with a LH sedan).

    Basically, your ac will benefit in every way imaginable from them.

    The argument about flammability is moot; although they are flammable, so is the r134 when mixed with oil under pressure. If managed safely and properly it is not dangerous.
    And everyone that is worried about that should probably not drive at all, being as you have 150 pounds of a highly volatile HC fuel riding right behind your body in a plastic container.


    I can understand someone maybe having trepidation about the flammability of it, but HC refrigerants ARE being used in all kinds If things today without any issue.
     
    #18 manybrews, Jun 16, 2019
    Last edited: Jun 16, 2019
  19. Bob Lincoln

    Bob Lincoln "CHECK FAULT CODES"
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    He may have said that this refrigerant ruins the system because now it is contaminated and cannot be serviced by a professional shop. Once you have mixed certain refrigerants, you cannot contaminate your service equipment by working on these.
     
  20. manybrews

    manybrews Well-Known Member

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    That's kind of true. But it depends.
    While most shops are not going to be equipped to capture HC refrigerant, as long as its a true HC it can be legally vented into the atmosphere.
    After that, purging a system is the same regardless of refrigerant and there will be no intermixing.

    If someone did actually swap from a HFC to an HC, it is likely that they already had the r-134 reclaimed by a shop somewhere.
    This is under the assumption that it is being done by people that know what they're doing with a refrigeration system.
    If someone added an HC refrigerant to a system that currently had HFC in it, yes... that poses a capture problem.
    Some equipment can identify refrigerants, but most shops are not going to have that and are going to be basing their repairs on the sticker that is on the car.
    A properly converted system should theoretically have the conversion sticker mounted right next to the factory sticker.
     

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