How much 134a

[chris989]

Hello all,

89 v2500

I converted to a sanden compressor and the install was straight forward. That said,, I feel the pressures are wrong for the temperature and not sure if more ounces is the answer..

I have 36 ounces in there now,, i feel that is more than with the r4, but then i undercharged the pancaked compressor to keep the high side pressure lower and it was bitter cold. The compressors o-ring would fail after a few years.


I have all the right tools, yellow jacket gauges, pulled a vac, no leaks etc. As of now, I have ~30/210 psi. The 30 PSI feels low compared to the return line and vent temp. When driving it just never gets cold. 60s out of the vent using my infrared. (feels warmer)

The orifice is from the original r12 to 124 conversion.. I did not change it for the sanden. Not sure if there is a difference

anyone do this conversion? How many ounces? Are my reading indicative of air in the system? I hae read 3.5 pound for r12 and 3.2 for 134.. Feels like a lot??

Thanks,
Chris

[Willie Makeit]

I have always googled a pressure chart based on temperature then add or subtract refrigerant to meet the suggested pressures (high side & low side)

[kwmech]

Did you change out the drier and flush the system of all the old oil. been awhile since I've done a conversion but If I recall the 134 going in is supposed to 80% of the R12