A/C Recharge Instructions
09-22-2004, 06:56 PM
#16
RECHARGING THE A/C SYSTEM
CAUTION: The high side of the A/C system is under considerable pressure. If a can of refrigerant is connected to the high side service fitting, it may explode! The system must therefore be recharged by using the low side service fitting only. If you are not sure which fittings are which, do not attempt to recharge your air conditioner yourself. Wear eye protection and avoid direct contact with the refrigerant as it can cause frostbite on bare skin.
The basic recharging procedure goes as follows:
1. Identify the low side service fitting.
2. Determine the type of refrigerant required by the system. On most 1993 and older vehicles, this would be R12. On most 1994 and newer vehicles, it would be R134a.
CAUTION: R12 and R134a refrigerants are incompatible and must not be intermixed. Use the type of refrigerant required for your A/C system only. On most 1993 and newer vehicles, there's an identification decal or sticker that tells what kind of refrigerant is required. Also, the size and design of R134a and R12 service fittings are different to avoid cross-contamination.
3. Connect a can of refrigerant to a gauge set or recharging hose and valve set. Follow the equipment supplier's directions for making the connections.
4. Open the valve momentarily on the gauge set or hose to blow all air out of the line (this is necessary to keep from introducing air and moisture into your A/C system).
5. Connect the gauge set or hose to the low side A/C service fitting on the vehicle. This is usually located near the receiver/drier or accumulator, or suction side of the compressor.
6. CAUTION: Make sure the can of refrigerant is held in the upright position so only vapor enters the line. Do not tip the can sideways or upside down as doing so will allow liquid to enter the low pressure side of the A/C system (This may cause damage to the A/C compressor). Also, never heat the can to make it empty faster as doing so may cause the can to explode.
7. Start the engine and turn the A/C system on high. The compressor should be engaged or cycling on and off (it may be necessary to jump the compressor clutch directly to the battery if the system is extremely low on refrigerant to keep it engaged). Compressor suction will pull refrigerant vapor into the system and slowly empty the can. This can take up to 10 minutes or more, so don't be anxious.
8. When the can is empty, disconnect the charging hose from the service fitting. Use care when disconnecting the "empty" can from the gauge set or charging hose as it may contain some residual refrigerant.
9. Add additional cans of refrigerant as needed until the system is properly charged.
CAUTION: The most common mistake made by do-it-yourselfers is overcharging. Too much refrigerant can reduce cooling efficiency just the same as too little refrigerant. To work properly, the A/C system needs just the right amount. Always refer to the system capacity specs in a shop manual or other source to determine how much refrigerant is required. System capacities are specified in ounces. One can of refrigerant equals about 14 oz. Usually three to four cans is enough to fully recharge a typical passenger car A/C system that was empty. If the system is low, one or two cans of refrigerant are usually all that's required.
CAUTION: The high side of the A/C system is under considerable pressure. If a can of refrigerant is connected to the high side service fitting, it may explode! The system must therefore be recharged by using the low side service fitting only. If you are not sure which fittings are which, do not attempt to recharge your air conditioner yourself. Wear eye protection and avoid direct contact with the refrigerant as it can cause frostbite on bare skin.
The basic recharging procedure goes as follows:
1. Identify the low side service fitting.
2. Determine the type of refrigerant required by the system. On most 1993 and older vehicles, this would be R12. On most 1994 and newer vehicles, it would be R134a.
CAUTION: R12 and R134a refrigerants are incompatible and must not be intermixed. Use the type of refrigerant required for your A/C system only. On most 1993 and newer vehicles, there's an identification decal or sticker that tells what kind of refrigerant is required. Also, the size and design of R134a and R12 service fittings are different to avoid cross-contamination.
3. Connect a can of refrigerant to a gauge set or recharging hose and valve set. Follow the equipment supplier's directions for making the connections.
4. Open the valve momentarily on the gauge set or hose to blow all air out of the line (this is necessary to keep from introducing air and moisture into your A/C system).
5. Connect the gauge set or hose to the low side A/C service fitting on the vehicle. This is usually located near the receiver/drier or accumulator, or suction side of the compressor.
6. CAUTION: Make sure the can of refrigerant is held in the upright position so only vapor enters the line. Do not tip the can sideways or upside down as doing so will allow liquid to enter the low pressure side of the A/C system (This may cause damage to the A/C compressor). Also, never heat the can to make it empty faster as doing so may cause the can to explode.
7. Start the engine and turn the A/C system on high. The compressor should be engaged or cycling on and off (it may be necessary to jump the compressor clutch directly to the battery if the system is extremely low on refrigerant to keep it engaged). Compressor suction will pull refrigerant vapor into the system and slowly empty the can. This can take up to 10 minutes or more, so don't be anxious.
8. When the can is empty, disconnect the charging hose from the service fitting. Use care when disconnecting the "empty" can from the gauge set or charging hose as it may contain some residual refrigerant.
9. Add additional cans of refrigerant as needed until the system is properly charged.
CAUTION: The most common mistake made by do-it-yourselfers is overcharging. Too much refrigerant can reduce cooling efficiency just the same as too little refrigerant. To work properly, the A/C system needs just the right amount. Always refer to the system capacity specs in a shop manual or other source to determine how much refrigerant is required. System capacities are specified in ounces. One can of refrigerant equals about 14 oz. Usually three to four cans is enough to fully recharge a typical passenger car A/C system that was empty. If the system is low, one or two cans of refrigerant are usually all that's required.
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Millermatic (08-29-2021)
09-22-2004, 07:09 PM
#17
One more thing. If anyone wants to be able to charge their own R-12 system they must pass an exam ONLINE at http://www.escoinst.com/Section609.htm
I beleive its only $20.00 then you may buy R-12. its an open book format test so its easy as pie. Dont charge a system unless you know the dangers of working with such a volitle substance such as R-12. Our enviorment depends on you
Like i said the test is easy and fun knowing you can service yours and your friends, wifes, etc. cars. See ya. 
I beleive its only $20.00 then you may buy R-12. its an open book format test so its easy as pie. Dont charge a system unless you know the dangers of working with such a volitle substance such as R-12. Our enviorment depends on you
Like i said the test is easy and fun knowing you can service yours and your friends, wifes, etc. cars. See ya.
09-22-2004, 08:24 PM
#18
Addict
Rennlist Member
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All of the R-12 leaked out of my system through a hose connection. I had it repaired and a vacuum was pulled on the system. When refilling the system with R-12, would you recommend adding any mineral/ester oil? If so, how much (1/2 of capacity or?)
09-22-2004, 09:04 PM
#19
Three Wheelin'
Join Date: Jul 2002
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944-LT1,
Thanks for the good info. Perhaps you can also confirm two issues.
First, the SNAP rules require that any facility or repair shop that services an AC system must have proper recovery equipment. IIRC, this means you can't charge for doing this unless you have the recovery machine.
And second, it is now illegal to vent R12, R134a, or any replacement refrigerant.
So if you get the 609 certification, you can buy R12 to top off your car, but you cannot vent the system. And you cannot charge for wroking on someone else's car, although I doubt that many people here would even consider doing that.
Thanks for the good info. Perhaps you can also confirm two issues.
First, the SNAP rules require that any facility or repair shop that services an AC system must have proper recovery equipment. IIRC, this means you can't charge for doing this unless you have the recovery machine.
And second, it is now illegal to vent R12, R134a, or any replacement refrigerant.
So if you get the 609 certification, you can buy R12 to top off your car, but you cannot vent the system. And you cannot charge for wroking on someone else's car, although I doubt that many people here would even consider doing that.
09-22-2004, 09:07 PM
#20
Nordschleife Master
Originally Posted by Tom M'Guinn
I need to read-up on that. My system has a slow freon leak. I was planning to just add freon, rather than evacuate and refill. When the freon leaks, does the oil leak too? I would have thought not the oil stays behind. No?
09-22-2004, 09:21 PM
#21
When R-12 leaks out of a system it takes small quantities of oil with it. Check around the drier and along the firewall where those two lines go into the cabin, if there was a leak the oil sticks around that area and collects dust and debris so as a telltale sign of a leak, just like your home or buisness air conditioning systems. I believe right under the battery those two ports held by 10mm bolts. And, at the compressor. There is no real way of telling how much oil is in the system theres no dipstick or sight glass. see oil is circulated with the refrigerant thru the system even in the coils (evaporator and condensing) by heat. But, most of the oil is in the compressor. But, when all the R-12 leaks out it doesnt mean all the oil is gone as well. I would go get a can of the hotshot oil i believe and put that in there just to be safe that should do it or either take all components out and have them cleaned out thoroughly(that way you know exactly how much oil to put in), or, add just between 1/4 - 1/2 and hope for the best. Remember whenever you cut into the system to service it you MUST replace the drier Its just good habit. Refrigerant oil has a high affenity for water, be carefull. Either way you handle it if you had this repair done by a shop it should have been done right and they to be held accountable. But, if your doing it yourself take my advice as just that...advice dont hold me accountable. but, this is how its done.
09-22-2004, 09:49 PM
#22
First, the SNAP rules require that any facility or repair shop that services an AC system must have proper recovery equipment. IIRC, this means you can't charge for doing this unless you have the recovery machine.
And second, it is now illegal to vent R12, R134a, or any replacement refrigerant.
So if you get the 609 certification, you can buy R12 to top off your car, but you cannot vent the system. And you cannot charge for wroking on someone else's car, although I doubt that many people here would even consider doing that.
And second, it is now illegal to vent R12, R134a, or any replacement refrigerant.
So if you get the 609 certification, you can buy R12 to top off your car, but you cannot vent the system. And you cannot charge for wroking on someone else's car, although I doubt that many people here would even consider doing that.
Please, dont vent refrigerants into our atmosphere. My responses are for the doit yourselfers...Dont start charging your friends for this, because then you are held responsible for all that could happen. A/c systems are not cheap nor are they to be takin lightly. Also they could turn you in for money 
But no, i dont know the law on charging for services unless you have a permit and certification and the right equipment approved by the EPA for this line of work.
09-22-2004, 10:00 PM
#23
Race Car
Interesting, you need a certification in the US to buy R12?... In Canada, you don't need anything, all you need is a shop that sells it, or EBay =) I've done all my own A/C work for some time now. Also did my parent's cars (although they were R134A, so perhaps there is no certification for that in the US either?).
My advice if you have a leak, is pull the compressor, and drain it, drain all you can from the system, change the receiver dryer, and add the reccomended amount of oil for an empty system. That's what I did in mine. That way you know that you have the right amount in there. IIRC, the amount of oil in our systems is 90mL +/- 20mL, that's pretty generous. So if there's still a bit of oil in the system, it will still be within that +/- 20mL.
I would never 'top off' an A/C system, that's not a good idea. If there's a leak, have it evacuated, fix the leak, then re-fill the A/C system. Topping it off is just a way to poison our planet.
My advice if you have a leak, is pull the compressor, and drain it, drain all you can from the system, change the receiver dryer, and add the reccomended amount of oil for an empty system. That's what I did in mine. That way you know that you have the right amount in there. IIRC, the amount of oil in our systems is 90mL +/- 20mL, that's pretty generous. So if there's still a bit of oil in the system, it will still be within that +/- 20mL.
I would never 'top off' an A/C system, that's not a good idea. If there's a leak, have it evacuated, fix the leak, then re-fill the A/C system. Topping it off is just a way to poison our planet.
09-22-2004, 10:15 PM
#24
I would never 'top off' an A/C system, that's not a good idea. If there's a leak, have it evacuated, fix the leak, then re-fill the A/C system. Topping it off is just a way to poison our planet.
But, I also found this on pelican parts technical articles. VERY INTERESTING:
The biggest difference between a Porsche and the rest of the cars on the road is the amount of rubber hose that is needed to connect all these pieces together. In the past this was the biggest problem because all this hose had been made to purposely 'bleed' freon much like your skin bleeds air. The hose was actually pricked through the outer layer each inch or so to prevent the hose from blossoming from the pressure inside. What this meant was that Porsches were subject to the lose of much more Freon than the other cars and thus had to be topped up more often. That's the only downside.
Check out this whole article for your self at http://www.pelicanparts.com/techarti...ult_AC_faq.htm
Also, in their main index click on tech articles for whatever model you have and there is an A/C recharging topic. You guys already knew that i bet
