We can Trace some fault with running and standing pressure. when AC is turn ON then the pressure that appears on the gauge is Running Pressure and when AC is turn OFF then the pressure that appears on the gauge is Standing Pressure.
R22 Normal Running Pressure is 65 PSI to 70 PSI . If we have a long pipe connection so the running pressure will look high. with long Pipe connection running pressure should be 70 PSI to 80 PSI.
If R22 Running Pressure is 40 PSI or 50 PSI i mean that low form 65 PSI its mean that Gas is low or AC need service. If AC already service then we should charge Gas.
Standing Pressure if R22 is 150 PSi to 160 PSI. If standing pressure is more from 160 PSI or 170 PSI its mean that Gas is Over. If sanding Pressure is low from 150 PSI its mean that Gas is Low.
Running Pressure 65 psi Standing Pressure 150 to 160 psi
R410 A :
Running Pressure 115 to 125 psi Standing Pressure 230 to 260 psi
Standing Pressure 240 to 250 psi Running Pressure 110 to 115 psi