Upon arrival, I conducted a thorough inspection of the furnace system. The initial assessment revealed that the furnace was not responding to the thermostat commands. I checked the power supply and found it to be intact. Next, I examined the thermostat settings and confirmed they were correctly configured. I then proceeded to inspect the furnace's internal components, including the pilot light and ignition system. After identifying a malfunctioning ignition sensor, I replaced it and restored the furnace's functionality. Post-repair, I conducted a series of tests to ensure the furnace was operating efficiently and safely.