Tampa 928s

Do not open the high side !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

It takes a while for the gas to leave the can, is the can cold?

Bill Ball

If you have good vacuum, it will draw enough USUALLY to allow the compressor to start. If not, pull the low -pressure plug off the switch. This switch is located just to the left of the drier, pointing down. Jump across the 2 contacts in the plug, leaving it off for the time being. The compressor should run. If it does not, you have other problems - 1. bad freeze switch, 2. bad headunit (relay), 3. wire break, 4. bad compressor clutch.

It does help to immerse the can in a bucket of hot water.

Tampa 928s

Stupid ? you said you have R-12 the quick disconnect fittings are different for R-134 and R-12 unless you have the adapters, what are your pressure readings?

dr bob

It looks like the H-F gauge set is pretty 'universal'. The hoses have the standard 1/4" tapered fittings, and H-F includes adapters so the hoses can also be connected to the R-134a style camlock connectors.

The guidance in your process needs to include the following:

-- NEVER open the red valve. There may be times when you might need to during vacuuming, drawing oil in, and maybe during initial charging, but until you have a lot of experience, it's best to just leave it closed tight.

-- Do everything you possibly can to keep from pushing air into the system. That means purging the yellow hose section with freon before you introduce anything into your evacuated system. Repeat each time you change cans if you are charging from the small cans. Air will trash the performance of the system, and there's no home-brew recovery if you blunder.

-- Do NOT overcharge the system no matter how tempting it might seem. The system works in a delicate balance. Too much freon will cause problems with peformance and with system safety. Plus it can get expensive.


Have fun, be careful and safe, and post your results please.

Dean_Fuller

UPDATE! Wow...I know nothing about A/C but what I read....BUT I finally got it cold!

The yellow hose is directional. One end has a pin and the other is open. I Had it back wards. Changed the hose around and jumped the A/C clutch like Bill said and I have COLD A/C now. SWEET! Now I know I could do this again in no time. The system sucked all 3 cans in in now time. I will run it a few days and see how it does. THANKS guys for not letting me blow myself up....bad way to start a holiday weekend.

Dean_Fuller

Hi Brian...if your not going to use them heck ya...let me know what you want for them. Looking forward to meeting you.

Tampa 928s

3-cans thats 36 onces your system only holds 37, was it empty? If thats the case you will be doing this again real soon

Dean_Fuller

???? It was empty from a release of freon when I had to unbolt a fitting a few weeks ago. I have drawn vacuum multiple times and it holds with new o rings and a new dryer. Where is the problem???

Dean_Fuller

I don't understand this post...please explain. I did not use the quick disconnects in the end.

Bill Ball

3 cans might be right. What size were the cans? Which car was it? Does it have rear AC?

Dean_Fuller

Hi Bill
Its my 89 S4 with rear air.

Dean

Tony

oil?...or is it in the cans already?

Bill Ball

The majority of the oil should still be in there if it was just a lost charge nad none of the components were replaced.

3 cans, assuming 12 oz each is is 1020 gm. Supposed to be 1200 for 89 w/ rear air. You're a half can short. Yes, it will blow real cold, but this is not ideal.

Dean_Fuller

Thanks Bill....half a can will be tuff.

dr bob

You'll bleed half a can during the 4 hose purgings needed with the four cans. Follow the guidance relayed by Tampa928, charging at 1200-1500 RPM's. Watch the sight glass, and stop adding gas as you see the stream in there start to go solid with few bubbles. Sneak up on the point where there are no bubbles, allowing time to let the system stabilize between puffs of gas. STOP when the stream in the glass is just barely solid, with an occasional bubble. Watch your gas pressure carefully as you are adding gas. Your ultimate system pressures will vary based on ambient conditions, of course. Lower suction pressures mean lower evaporation temps, and that means coldest evap temps if you are delivering liquid to a properly-operating expansion valve. 25-35 PSI is a good range. At the same time, the high-side pressures reflect the amount of heat remaining in the liquid, related to ambient temp, airflow, condenser and compressor efficiency. Lower is better again, with 250-275 common on hottest days with the car sitting still (your charging/test conditions). Anything above 300 PSI is cause for serious concern, so don't add any more gas if pressures exceed 275 PSI no matter what the sight glass is telling you.