I did the conversion from r12 to r134a. I work at a shop that does the leak down test and evacuated the entire system. How many lbs of r134a do I need to put into the system?
CHARGE WEIGHT
2.5 LBS / 1.15 KGR
MIN.TEST PRESSURE
LOW SIDE 140 PSI
HIGH SIDE 300 PSI
OIL: 0.28 kg / 10.0 oz**
AC PRESSURE SWITCH ON: 3.1kg/cm2 - OFF: 1.7kg/cm2
These figures are for R12, must be conversion charts on the net.
Another way is until you see no bubbles at the sight glass.
TheR143a charge weight is GENERALLY 80% of the R12 charge weight.
1 Like
low side pressure is more important than a specific fill amount. 35-40 PSI at 75F or 45-50 at 90F is what you are looking for. With r134a I go with the lowest pressure I can that gets me cold air. Everything lasts longer that way. With a conversion where the components are designed to get the most out of R12, more R134a is not better. The 80% that motorcarman mentioned is a good rule of thumb.
2 Likes
OLD TSB for the V12 cars but the XJ6 uses the same Harrison Compressor.
82-39am R-134a Retrofits Kits.pdf (25.9 KB)
Awesome so you guys are recommending about 2lbs?