System was previously found low on refrigerant on July 16, when dye and refrigerant were added. Follow-up inspection performed today. No evidence of UV dye detected at this time. Major oil buildup observed at sweat weld joint on suction line into condenser is an indicator of a leak but leak could not be confirmed. UV light and bubble testing performed with no definitive result. No UV dye observed in drain line. Evaporator coil inspection would be labour intensive due to venting removal requirements. Checked system pressures: readings matched those taken by Trevor on July 16 (superheat measured at 18). Recommendation: Return in the spring for recheck. If system is found low on refrigerant, perform a second search for UV dye or recover refrigerant and complete a pressure test to pinpoint the leak. Client agreed this is the best course of action and will monitor the performance of the air conditioner for now.