Ok, cool.
I guess I am tryig to find out if its practical to have a R12 set of filters and tanks, and the same for R134a, and purge the lines between uses... or just take it to the shop to have the r134 removed...
I have a good Vacuum pump, and I guess I could just refill using cans..

Please tell me where you got the filters.

Thank you.

I will have to look for where I got the filters...

Does anyone have an Owners Manual for the ACT 3120... mine didnt come with one..

Congrats on the purchase!

Here should be some info on the unit:
ACT-3120/3340 PRODUCT INFO

http://equiserv.com/Common/Instructions/Product/ACT3120B.pdf
http://equiserv.com/Common/Instructions/Product/ACT3120A.pdf

Thanks.
In fact I already had that one...
I decided to Email Snap-On Customer Service... and 24 hours later I have a PDF of the Operators Manual!
Kudos to you guys at Snap-on!

Now, the fun starts...
I was given 2 tanks with the unit.

I took one of the tanks, that I was told was empty, and checked it, and felt empty, but to be sure I evacuated it into the other tank... pulled a 25hg vacuum on it for 30 mins.
I then put that tank on the scale in the unit... and it read empty... so good so far.

I connected the gauges to my 190e which had a leaking sight glass on the Receiver/Dryer, so I needed to evac the R12 before replacing it.

Static pressure was 65psi with the ambient yesterday of about 60degF.
I ran the yellow hose from the gauges to the 3120. and told the machine to evac..
It pulled 14oz out.... but I discovered the empty tank has a problem... there was a slight leak at the tank hand wheel seal. I could not hear it above the noise of the pump until it stopped. I immediately sealed the tank.
I then swapped tanks, and pulled that 14oz into the other tank, which is good.
The part full tank has about 5lb of R12 in it according to the scale.

I removed and drained the old drier, I measured about 25gramms of oil, so put the same omount of oil in the new one, swapped the sensors, replaced the O rings and we were all sealed again in 15 mins.

Using the 3120, I set up the Auto Sequence to pull 25hgof Vacuum for an hour, hold it for an hour to measure any leaks and then charge the system.

Here is where it got odd...
The sticker under the hood says 2.2lb or 1kg of R12.
I tried to enter that, and I got an error... I ended up telling it to put in 16oz.

The machine did its thing, and started to charge.. I had the engine running at idle and after the first few seconds the Compressor kicked in.

After a while the machine beeped and signalled it had charged the 16oz.
At idle the gauges were reading about 225psi High side and 30psi low.

I left it overnight and today I see the static pressure is 110psi.... with half the charge that it should have in there...

Did I miss something?

snap-on ACT3340 charging station
 

This charging station has a code 8 displaying and will not respond on clearing code. I called the tech hotline and they keep saying if its under warranty we will send a tech out, but the machine is over 15 years old and snap-on says they have no info on it even though it is a snap-on machine.

Snap-On would not have made the machine. Maybe made by Robinair?
Perhaps you will have more luck trying to find info on a similar Robinair unit. Maybe open it up and see if the manufacturer is marked anywhere, maybe on the circuit board(s).

I got the r4 compressor for less than 130 new and installed and charged for another 100.

You may want to check around, but go in there knowledgeable.