Unit off upon arrival. Turned it on to test operation. System did not leaking while running. Drain line clean, all fittings clean. Indoor coil clean. Opened up coil, coil is pitched correctly. Filled drain pan up to rim. Held water without leaking. Customer said he has construction work done in basement recently. Filter was plugged enough to were it was warped. More than likely unit had froze up from a dirty filter. Adjusted airflow from 1050 cfm to 1250 for 3 tons of cooling. Swapped filter out and performed a cleaning on outdoor coil. Refrigerant pressures are now low after cleaning it. System has a refrigerant leak. System may freeze up again now with where the pressures are at. Due to age and condition, would encourage looking into replacement. Brandon will be meeting with you next week Wednesday at 3pm to quote replacement.