A/C Problems.......Stumped

Hate to be the bearer of bad news but if your system was blown up, you're going to need to replace the condenser and evaporator too. And because you didn't do it the first time, the dryer and the orifice tube will need replaced again as well.

You can flush a short section of line with CHLORINATED Brakleen (red can), but I'd replace long stretches.

 

Oh, and 5.5 lbs is 7.3 of the 12 Oz cans.

Drain the oil out of the compressor, measure it and replace it with exactly that much fresh oil. Plus another 4 oz. for the components you replaced.

 

They are just about impossible to flush clean (as you saw by the orifice tube plugging up). And depending on the design, some of them absolutely should not be flushed.

It doesn't take very much crud at all to plug up the orifice tube screen. When the orifice tube screen is blocked, the compressor is getting no oil and will burn up in short order.

 

The small passages inside the evap and condensor can get plugged up with debris. Also, did you vacuum out the system before recharging?

 

The refrigerant capacity is still the same regardless of whether or not you use the rear air. The orifice tube and evaporator back there will also need to be replaced.

Alternatively, if you don't use the rear air ever, just cut and crimp the lines then braze them shut with aluminum brazing rod. Then get a filter drier with a sight glass in the liquid line to determine when the system is full.

Be sure to vacuum the system down with a vacuum pump. Moisture and air are the mortal enemy in any refrigerant system.

 

It's freezing because the orifice tube is partially plugged. When that happens the pressure on the low side will be too low and will freeze just beyond the point of restriction.

If your low pressure cycling switch is working, the compressor should be turning off once the pressure gets below a setpoint, usually 21 psi.

Alternatively, some systems use a thermostatic switch with a sensing bulb in the evaporator to check for freezing. In this case, your system may not have a low pressure cycling switch.