[Richard]

Jon,

The only part where I disagree with your logic and tech's input is the compressor output pressure. 130 psig is not normal in my experience, it is about 100 psi low. Can you point me to the sources which are indicating that 130 high side for R22 is normal?

Let me give you some data from my SCS system. I AM dealing with a clogged TXV valve. I replaced the compressor over the winter but that may not have been the original problem. Before the replacement surgery the system did not have ports to check pressures. So anyhoo, my pressures with a clogged TXV were 0 to -5 psig low and 300 high. Early in the diagnostic process I added refrigerant to see how the pressures would respond. Raised the low side to 30 (still low) and the high side went to 450. This is all with R 22, the same gas you are using. Real techs always replace TXVs when they replace a compressor. I learned the lesson the hard way.

I understand your point about the pump rattling because it's starved. I would still put some gas in it and see what happens as you raise the low side.

I understand about the tool drool. I went through the same route. You can get your license through taking an on line course. With your chemistry background it will be a cakewalk. Tools are going to be expensive. Oxy Actylene torch 350, vac pump 200, gauges 125, N2 setup 150, and a bottle of R22 300. Those are off the top of my head guestimates, but I post so that those who balk at AC tech charges will understand what it takes to even start working on a system.