First of all you need to know refrigerant is COLD!! I've suffered 2nd degree burns from it.


Second you should never empty any refrigerant into the ozone unless your sure its 134a. You can be fined up to $10,000 if someone catches you dumping freon thats not ozone friendly.





If you want to do it right and do it yourself you can pick up a set of 134a refrigerant gauges(charging manifold) and a good used refrigerant vacuum pump for around a $100. You can buy small cans of 134a at any auto parts store but its cheaper to buy it in bulk. Sam's club sells a 30 pound can for $77


You can usually find good used tools at pawn shops for much cheaper than new!
If you buy a vacuum pump used you need to replace the oil in it. If you buy your refrigerant gauges used you need to purge them with compressed nitrogen or you can use 134A. (nitrogen is much cheaper than 134a, its good to use for leak detection, and it will actually absorb moisture)
Its very important that you purge your gauges just in case the previous owner used them with other refrigerants. Different refrigerant's use different oils and the combination of certain oils can cause problems.


If your looking to save some money you really don't need to pull a vacuum on your refrigeration system. Purging the lines with refrigerant will help to get the majority of the air and some moisture out of the lines. It wont do as good as pulling a vacuum does but your AC will work!








To Pull a vacuum on your system hook your gauges up to both ac ports on the car.

Yellow (center on the manifold) hose hooks to your vacuum pump and refrigerant tank

Red (right on the manifold) hose is for your Liquid line set (smaller line in your ac system) used for trouble shooting problems with the AC by experienced HVAC Technician's

Blue (left on the manifold) hose is for vapor line set (larger line in your ac system) You'll use this to add refrigerant. The blue gauge is what you read when pulling a vacuum or charging your system.



Once you have your hoses hooked up tight make sure both of your valves are open on your gauges.

You need to be sure that all your hoses are tight so you get an accurate reading with your gauges.

Its time to turn your pump on!

After your pump is on and running connect the yellow hose

Let the pump run till the pressure on your blue gauge gets down to -30 psi.

Once at -30 let it run for about 10 min.

After 10 min close your gauges valves before you turn the vacuum pump off!!

Again make sure you close your valve's up tight!

Let it set for at least 10 min.

If it stays at -30 psi you shouldn't have any leaks. Now you can disconnect the yellow hose from the vacuum pump and hook it up to the refrigerant tank.

Loosen up the yellow hose at the gauges so its only hanging on by two or three threads.

For the next step BE CAREFUL!! Refrigerant is COLD!!

Open the refrigerant up a little to let it purge any air/moister out of the loose fitting than tighten your loose fitting while the refrigerant is still flowing through the hose.

The reason you do this is you have gotten air and maybe moisture into your yellow hose after you disconnecting it from the vacuum pump.

Once the yellow hose is tightened on both ends you can open the refrigerant bottle all the way.




(You need to purge or pull a vacuum before you put refrigerant into your line set) See the bottom for purging instructions







Now your ready to add refrigerant to your vehicle!

Before you start adding refrigerant you need to start your car and turn your AC on.

Start by adding refrigerant liquid into the vapor line.

To do so you turn the refrigerant tank upside down and open the blue valve on your gauges.

Your compressor wont engage until you have enough pressure in the line set of your auto.

Once there is a little refrigerant in your line set the AC compressor will begin to cycle on and off. Once this starts you can see the pressure fluctuating on your gauges.

Again you need to keep an eye on your blue gauge. When your compressor turns on you'll see your pressure drop than your compressor will turn off. Your pressure will rise, the compressor will turn on, than pressure will drop again, the compressor will turn off again and your pressure will rise.

Whats happening is there is a low pressure safety switch that will continue to turn your compressor off. It will continue to do this until you have enough refrigerant in your AC System to keep the compressor from pulling the pressure below the set psi. Be sure to keep your eye on the blue gauge so you'll know what psi the compressor is turning off because of the safety switch.

Once you compressor runs constantly close the blue valve on your gauge manifold.

Turn your refrigerant tank back over, this will add refrigerant vapor instead of liquid.

The vapor pressure will very depending on humidity, temperature, and the style of your AC system. With out knowing everybody's circumstances I don't want to post what your pressure should be.

Your best bet is to find where your fan is sucking in air (known as the return air) Take a thermometer and move it back and forth from the return air and your supply vent to see how many degree's the air has cooled across the evaporator coil inside your dash. Be sure to let the thermometer set in each spot until the temperature stops changing

Slowly add refrigerant vapor until the difference between your return air and supply air stops growing.

A 20 degree's difference is the average cooling you'll see but don't get discouraged if your not getting that. You might need to clean your condenser coil, evaporator coil, or an air filter. An inadequate radiator fan will cause a poor cooling too.




Hope this helps. If any thing doesn't make sense let me know because I don't feel like prof reading this right now lol!







To purge your lines just hook up 134a refrigerant or nitrogen up and both hoses from your gauge manifold.

Disconnect the blue hose from your gauge manifold and close the blue valve.

Once your nitrogen or 134a bottle is open and you have a good hold of the lose hose pointed away from anything that can be damaged by very cold gas open the liquid valve on your gauge manifold.

Leave the valve it open 10-20 seconds after you have gas coming out of the lose hose.

Close the red valve till you have a very small amount of gas coming out of the lose hose.

Now quickly and carefully reconnect the lose hose and start charging!

 

Nice write up

Bill

 

Thanks, I'm pretty sure I've never seen a sticky on AC but I always see people having AC problems so I hope it helps.

If someone see's something I missed or something else that would help feel free to post it.
I'll throw it in my post and take full credit for it

 

Nice write up I only have one suggestion, "Freon" is a name brand, So every time some-one says "Freon" it like grouping all nitrous oxide systems in to one group called "NOS!!!"

 

I have two uncles that have owned there own Heating & Air Companies since I before I could walk. I grew up helping them on the weekends and I've worked in the trade full time for over 5 years now and I did not know that!

 

LOL You called it freon. Everyone knows it's called dichlorodifluoromethane. J/K

Thanks for posting this. I tried to do this myself once and I was afraid the can was going to explode or something. I'll follow these directions next time.

 

aaa, not sure how to take that post with the smiley.... I didn't mean to bash on your parade, I know how much work it takes to write something like this, and I'm sure it will help everyone that attempts any kind of A/C repair. For some reason it drives me crazy when someone misnames a part, say like a starter... It's not a starter, it is a cranking motor. It does not "Start" the engine, compression, fuel/air, and spark, starts it...lol I know I'm OT..... ANYWAY NICE WRITE-UP! And thanks for fixing it LMAO

 

<-- "humbled smiley" lol! Its no problem at all! Since you told me that I've busted all my suppliers *****! To think I trusted them.... lol!

 

I agree with everything except the part about "if you want to save money you dont have to pull a vacuum". If you are charging your ac it is for one of two reasons 1) you have a leak 2) you have opened up the system. In both cases you MUST pull a vacuum. If you had a leak you need to pull a vacuum to insure the leak was repaired properly and you are not losing pressure and to remove any moisture from the system. If you have opened the system for any lenght of time you must pull a vacuum to remove moisture from the lines. If you do not remove moisture from the lines your compressor will fail pre-maturely as it is very difficult for the valves to compress watter molecules. Oh, and you should NEVER vent any form of "freon" reguardless what kind it is.

 

Your refirgerant line are going to have a positive pressure once charged so why would you check for leaks using a negative pressure? Use nitrogen to leak check than purge with it. The nitrogen will absorb most of the moister. Than purge with your 134a to remove most of the oxygen and your good to go. One more thing is you should NEVER leave the lines open, If your waiting on parts tape them up!!

134a is ozone friendly