On arrival found mini split off. Resting pressure does not immediately indicate deficit. Reset system as part of initial diagnostic and found suction pressure falling below 40psig. Blower active and filters relatively clean. Liquid line frosting over. System not reporting any errors, likely due to system reset. Assuming refrigerant low or system restricted; left system on in hopes that code will be present on return visit. Return with R-32, check system codes and continue diagnostic as needed.