Need help with AC Charging Gun/Freon Canister

[glenmore]

I thought I would try this AC charging gun with two of the kid's cars that just lost their cold air.

http://www.amazon.com/dp/B002G1PAZ6/?tag=atomicindus08-20

I twisted on a 12oz can of R134a and tried to charge the two cars. I have never done this before but after about 20 minutes of no change to the pressure or cold air, I gave up. I tried it on the second car and same thing. On a 3rd car, with an OK AC, the pressure read correctly at 45 while with the other 2 cars, never got much above 25-30.

When shaking the gun and canister, you could tell that the cannister was still pretty full of freon and probably none of it got into the car.

I called the Interdynamics Hotline and went over it with the tech. He said that the freon usually empties in about 5 minutes and that the can usually gets quite cold. This never happened when I was attempting to charge. So it appears that the gun is clogged somehow and not able to deliver freon. Included with the gun was a male air hose fitting, same as a low pressure port fitting. When you fit this on the hose coupling and press the trigger, freon should come out but nothing does. The guy said to send it in to check out. We talked about the attached cannister but he refused to suggest a way to get it off.

Problem: In order to send the gun back to be checked, I have to get what is probably a full 12oz can of freon off the gun.

How to do this....safely?

 

[Bran Diezel]

was the car running and the compressor running when you tried this?

 

[glenmore]

Yes, car running, AC going full blast, clutch engaged.

 

[jayoldschool]

Make sure you have the can pierced. It sounds like you haven't punctured the can. Unscrew the gun a little from the can. It should make a hissing noise. Be careful, and just do this real fast. Gloves and eye protection are a great idea. I have never used that "gun" style before. Most setups just have a can tap where you screw a butterfly valve that causes the can to pierce, then you back off the butterfly to let the R134a to flow.

Make sure you are connected to the LOW side!

Raise the RPM of the car to 2000. This is what GM specs to charge at. This will pull the charge in quickly. Also, shake the can while charging, and alternate between vertical and 3:00 every three seconds. Don't use anything other than pure R134a. NO SEALERS!

 

[glenmore]

Jayoldschool,

That makes sense, the can is not pierced yet! When I attach the the air fitting and press the trigger, nothing comes out. When I hooked it up to a good AC system, it reads the pressure correctly, so connection to gauge is good. I've tightened the tool completely onto the can. According to the instructions, that is all that's done. No backing off the piercing element to allow the freon to flow.

This is actually my worse case scenario, a can that is almost pierced. I would have preferred a pierced can and plugged tool that I could vent (sorry environmentalists) and then return for repair.

Time for the face mask and gloves.

 

[MechanicNamedJohn]

Put the can in warm water while you are charging.

 

[jayoldschool]

You don't need to do that if you use the proper RPM on the engine.