I arrived for a club member thermostat going blank issue. I spoke with the homeowner and found that the thermostat first went blank and the system stopped cooling and the temperature in the house went up. I also found out that they had put batteries in the thermostat that has a C wire for it to run off the power of the system. I then inspected the system and found that this system has a drain safety switch and is stopping the 24V power that is running the low voltage side of the system. The drain line is stopped up and causing the system to loose power and shut the system off. This is a safety feature that prevents the system from continuing to run and have water overflow into the sheet rock and damage the ceiling. I found the safety switch to be full of water and the main drain line to be full of water. I cut the drain line and installed a Jones valve and used dry nitrogen to blow out the clogged drain line and what water the system was holding. This drain line is about 30-40’ long an