Silver club furnace tune up on 2020 Comfort Maker 90% split system. Spoke with customer about last issues of smell, etc and that has rectified itself with the UVC lamp. Customer did have an issue with thermostat shutting off even though the furnace had power sporadically. Inspected wiring and found yellow white and green to be poorly cleaned and connected. Properly attached wiring and cleaned up contact points. Inspected thermostat wiring at furnace and it is in good condition. Customer has a T4 pro Honeywell, talked to them about getting a T6 pro which has a battery backup and can just be replaced with the face. Checked blower, control board, 4†filter, heat exchanger from below and flue. Checked drain line, UVC lamp, inducer wiring and tubes and cleaned flame sensor. Cycled system on and checked heat rise, carbon monoxide, and adjusted gas pressure to 3.5†W.C. It is a newer home addition, so gas pressure may need to be adjusted annually. Checked static pressure. System running