A/c repair call. Tested system and found very rusty, corroded evaporator coil. Found system with no water safety switch and is therefore not up to today's code. Found dirty blower wheel. Filter was dirty and clogged, changed filter. The system is low on r22. Customer wants to recharge system for now until it can be replaced. Recharged the system with 4 lbs r22. The customer understands there is a leak and that refrigerant will leak back out again. No guarantee on how long the refrigerant charge will last. The system is cooling at this time.