Service diagnostic found the primary drain line was clogged. I spoke with homeowner and he said he wanted to try removing the trap at the sink first before having me clear out the drain. After he removed the trap, he found it was backed up at the drain line and sink connection and chose to have me service the drain line. I cleaned, cleared and tested the drain line with 3 gallons of water. I then treated the drain line and cycled power at the thermostat. No other issues were found. The system is operational at completion of service.