Technician found system low on refrigerant. Will need to recover existing refrigerant. Perform a nitrogen leak search. Attempt to repair leak if found. Install new filter drier. Pull vacuum. Convert to R427a refrigerant to include ac renew. More quotes may follow. Ambient Edge recommends system replacement over repairs due to age and condition. Returned to site. Checked in with management. RTU #3: Performed leak search with electronic leak detector. Inspected evap and condenser coils for any leaks. No leaks detected in coils. Found leak to be at the discharge king valve. Attached a T-fitting connector to the king valve to stop leak. Found secondary drain pan with lots of condensate water in it, indicating a drain problem in the primary drain line. Cut the primary drain line to blast nitrogen pressure through the line to clear it of any debris. Reconnected primary drain line with a pvc coupling. RTU#3 air handler: Found secondary drain pan with a drain line that is sloped upwards,