A/C units rooftop 1.5 to 2 tons, evaperator does not have schrader valve at evap.I can not measure PSI of low side,
can I just measure it at the compresor, can I add 2-3 PSI
for an average pressure loss in the refrigerant line from the
evaporator to the compressor.Now if that's so,I would be ading PSI to the low side compresor reading,
if I were to do this on the high side at compresor to evaperator will I be substacting PSI instead of adding ?