Service diagnostic found that the condensation drain line was clogged. Water had backed up into the safety switch and shut down the system. Options for repair were presented to the homeowner and he chose to have the drain line cleared. I cleared the drain line and flow tested the drain with two gallons of water. Clear water was observed flowing out of the drain line. I then treated the drain line. I function tested the system and the system is now operational. Everything is running at the completion of service.