I successfully charged up my Vintage Air system this weekend (I think). I had zero knowledge about A/C systems so am definitely a novice. I guess I was successful since the refrigerant cans are empty and it's blowing cold air, but there were definitely some challenges along the way. Here is what I learned.
Per the Vintage Air instructions, I didn't plumb in the dryer and trinary switch until the system was ready to be evacuated, which meant I couldn't put my front bumper on until after this was done. Wasn't really comfortable driving it to a shop without a bumper, so it became a convenience thing being able to do it all in my driveway in the proper sequence. To minimize the time the dryer was exposed to the atmosphere, I had everything hooked up and ready to evacuate as soon as I plumbed everything in. While waiting for the system to evacuate I wired up the trinary switch.
I watched all the YouTube videos I could find and found the ChrisFix channel the most useful for this topic. The concept is pretty straightforward, evacuate the system and fill with R-134a, but because of the number of steps involved I decided to create a detailed checklist to use during the process. This turned out to be a huge help but there were still five things I wasn't quite sure of.
1) Some YouTube "experts" said to turn the refrigerant can upside down when charging and others said not to so that was confusing. The instructions on the can say to agitate and only flip the can from 12:00 to 3:00 o'clock position so I went with what the can said.
2) The R134a cans I bought were the small 12 oz ones. The Vintage Air system requires 28.8 oz so three cans were needed. Sounds like simple math to figure out how much of the third can you need but most on YouTube didn't take into account the amount you lose in filling the hoses, purging air out of the hose, and switching cans. Through more research I read that you lose about 2 oz in the hose itself but there really isn't a good way to measure this and it depends on how long your hoses are. If you know what you are doing I guess you go by the pressure gauge but my pressures didn't seem to jive with what Vintage Air said to expect. I ended up using a digital scale and went by weight of the cans.
3) The R134a cans I can buy in California are the newer style with the schrader valve instead of the puncture top. Not sure if this is a nationwide thing or just in California. But it got confusing as to how to use these and also how to switch cans with this type of tap. The tap valve closed position is all the way down with the plunger sticking out. This is the opposite of what I would expect with a schrader valve can, but I couldn't confirm anywhere exactly how the cans work. Putting on the first can works fine, open the tap valve (out), screw onto the refrigerant can, then close the tap valve (in) to puncture. But that means the tap valve is closed so you need to open the tap valve (out) to release the refrigerant. The confusing part is it seems logical that if you open the tap valve too much then the schrader valve on the can closes. I might be wrong on this but I couldn't find anything to confirm exactly how these work.
4) With the first can you have to purge the air out of the yellow refrigerant line. I had actually bought a second manifold gauge set because the first set didn't have a purge valve on the refrigerant line. Unfortunately that set had leaky hoses (another issue to watch out for with the cheap sets) so I ended up using the set without a purge valve. Supposedly the way to purge this style is to crack open the screw down connection to let the air out until the refrigerant is vented. Did this but I never saw any refrigerant come out. I purged the air until the can was down 3 oz based on it's weight, so I assumed that I got all the air out but still not sure. The other weird thing is that I never saw any refrigerant pass through the sight glass on the manifold when charging. I was expecting to see something in both of these steps.
5) To switch to the second and third cans it seems logical that in order to not re-introduce air into the yellow refrigerant line that the can tap valve should be closed. But this means the plunger is out and you can't screw it onto the can without losing some refrigerant that way. So this is another confusing step which no one on YouTube addressed. What I did was leave the tap valve closed and screwed it onto the can as quickly as possible. I assume I lost maybe 1 oz of refrigerant this way for each can and factored this into total refrigerant volume. If I did it again, I would add a small brass gate valve to the can end of the yellow hose so that I can isolate the refrigerant in the line while switching cans, then use the same process as when attaching the first can but without the need to re-fill the line and purge the air.
Bottom line is that I'm not positive if I put in enough refrigerant, although I guess too little is better than overfilling. Plus it's blowing out at 42 degrees (ambient was around 90) so that's on target.
Total cost for the tools (manifold gauge set, vacuum pump, new style can tap valve) and refrigerant was just under $140. The A/C shop charges $175 so came out ahead there.
