Performed heater tune-up on a Carrier infinity furnace system. Checked the electrical, mechanical and performance systems of the unit. Cleared, cleaned, flushed and treated the drain line and cleaned the exterior of the furnace system. Replaced the high voltage wire nuts with a wago wire connector. I also found the water safety switch was not wired in correctly. I rewired the water safety switch and set up G Terminal Shutdown on the thermostat. Function checked the safety switch. No other issues were found. The system is operational at this time.