What should be the first step when troubleshooting an oil heating system?

When troubleshooting an oil heating system, the initial step should be to check the power supply. This is crucial because many components of the system, including the burner and the control system, rely on electrical power to operate effectively. If there is no power, or if the power is insufficient, the entire system can fail to function—rendering efforts to troubleshoot other components ineffective.

By verifying the power supply, you can determine if the problem stems from a lack of electricity reaching the system, such as a blown fuse, tripped breaker, or faulty wiring. Once the power supply is confirmed to be working, you can then move on to assess other aspects of the heating system, such as the oil supply, burner motor, or chimney. Ensuring adequate power is fundamental to diagnosing the system's operational issues accurately.