It's about that time of year. I replaced everything: evap, condenser, compressor, filter, expansion valve. But now about a week later it doesnt work. The compressor kicks on but no cold air. Plenty of coolant. Whats the deal?

 

Did you pull a vacumum on the system before recharging it? By "filter" do you mean the reciever/dryer? What I'm getting at is there may be moisture in the system thats freezing up.

 

Why did you have to replace everything? Did you have a major compressor failure? If so, did you clean/flush all the lines out. I have had debris get left in the lines after a major failure and days later plug up the valve. Did you "pull" really good vacuum on the system and it held it for at least 20min without a drop in vacuum? It take time to "boil out" any moisture in the system if its been opened up. As mt_goat said, even a small amount can "freeze up" your system. Whats the cycle times [on, then off] of the compressor and can you get/tell us what the High and Low side readings are? What refrigerant are you using/did you put back in, and how much?

 

I replaced everything b/c it was old and rusted. Compressor clutch was bad and the compressor itself was original with r12. I cleaned everything and put a vacuum on for about an hour and then let it sit for an hour after to ensure no leaks. I forget the high/low readings but I will get them. I remember them being good but ill check. using 134. Yes I mean dryer. I put enough in to get the right pressure.

 

Close yer heater valve, or I should say make sure it closes

 

it closes

 

how did you apply a vacumn? Do you have a vac pump or some sort of tool for that purpose? Im courting an AC problem and would like to open the system up and be able to close it and vac it back up. What are you using to get a vacumn? thanks.

 

I used a basic a/c evac from autozone. They let you borrow them.

 

Just a wild shot here, but you do know that too much freon is as bad as too little right?

Sure you're not overfilled?

 

I thought about that. All I have to go off of is the pressure.

 

Is your system converted for 134? An R12 system filled with R134 can eventually leak out, i'm not sure of the specifics, but fittings, bushings and/or washers etc. will corrode over time and cause failures unless they are replaced with the correct fittings, bushings and/or washers.

 

I converted to 134, the right way. not just changing fittings. but the pressure is there.

 

could the expansion valve gotten clogged somehow?

 

When reinstalling the refrigerant, the most accurate way to insure the proper amount of refrigerant is to "weight" it. Also, most convertions will have you put in more of R134 that what the old system took to operate on R12[which worked better, but kills the ozone]. How much new R134 compatible oil did you put into it? Did you upgrade the O-rings to ones that are compatable to R134, There is a differance between the two types.

Unless you have reason to believe that there would be any debris inside the system,[it was still a sealed system?] and you did not have a internal failure did you? I would say its not very likely that the exp valve/orifice is plugged.
Best Guess right now, its low on refrigerant, but to diagnose it further, we need those pressure readings and cycle times, as well as the ambient temp they where taken at.

Which: make/model/year/engine size are we looking at and how many lb/oz of R12 did the old system call for?

 

Ok, so the high-side pressure is 45 psi, is that too high? It does not seem to cycle at all, just stays on. Maybe I didn't leave it on long enough.

 

Or, what if there is air in the system?

 

Air=moisture, especially in Texas right?

 

What confuses me is that it held a perfect vaccum for over an hour with no change. The little window on the top of the accumulator looks like there is air flowing, but I'm not sure.

 

I'm in north Texas were it's not that humid.

 

Hmmm...I lived in Wichita Falls for 5 years, it seemed pretty humid to me. It was no Arizona or Colorado anyway.