Spring Air Conditioning Maintenance Service in McKinney. Performed a one system maintenance checking cooling, checked indoor units electrical, mechanical and safety components. Blew out drain, checked filter, checked coil and found a good amount of rust on evaporator coil possibly leaking. Checked outdoor units pressures, amp draws and capacitor. Found all components good. I did find that the system is slightly low on refrigerant, system hold 8lbs and is about 1-2lbs low.