Connect your gauges and check sc for txv, or check sh for fixed orifice. Also need to verify airflow before you check either of the above. Improper air flow will give false readings. After everything is checked, then as a last step, verify what you did with a delta T reading across the eveporator coil. You should be somewhere between 16 and 19 on the delta t reading.What's the best & fastest way to check if residential home system has enough refrigerent to run the sytem?