Larry, I know you are quite experienced in a/c repair and have recovery equipment, so I think this is a question you can answer - how do I hook up the hoses to recover refrigerant? I was reading the manual for my machine and it has a diagram that shows the low side hose is hooked between the machine to be recovered and the gauge manifold, the center (yellow) hose is hooked the the recovery machine input, the recovery output is hooked to the liquid line on the recovery tank, and the vapor outlet on the tank is hooked to the high side on the gauge/manifold.

My question, based on the above diagram (I hope you can follow my description!) is what side of the car's a/c system do you attach the low side of the manifold to? The high side or the low side? It seems like you would want to attach the manifold high side line to the high side on the car, and the low side to the low side, then attach the yellow line to the recovery machine, but the directions for the recover machine state that you need to regulate the recover machine's output pressure by adjusting the low side valve on the manifold as it is recovering.

The machine I bought is second-hand off of ebay, and I've never used one before, so I hope you (or someone) can give me some guidance. I just don't know if I can recover all the r-12 from my 300CE from just the high side, or just the low, side. The high and low sides are sort or separated by the compressor and expansion valve, so I'm worried just hooking up to one side won't thoroughly evacuate.

Thanks.

GregS

'84 300D, 183k
'90 300CE, 173k

I can't speak for your machine because I don't know what kind it is, but your first paragraph does not sound right to me. Your second paragraph is the way I use my machine.

I hook up my manifold gauges normally and then hook the center hose to my recovery/recycle machine.

Basically these machines allow the pressure of the system to force the refrigerant still remaining in the system into the recovery tank until it no longer has pressure to cause flow. Then the machine provides a vacuum to draw the remaining refrigerant, mostly for environmental reasons to ensure that there is none left in the system to escape to the atmosphere.

You can open both sides of the manifold while recovering because you must do this with the engine off and the system not running. If you do it all through the low side it will take much longer.

Good luck,