During a proper tune-up, what should you check first?

During a proper tune-up, the first step should involve checking the tank for water. This is crucial because water intrusion in an oil tank can lead to significant problems, such as corrosion, which can compromise the integrity of the tank and the overall heating system. Water can also cause issues like fuel contamination, resulting in poor combustion and inefficient operation. If water is present, it's essential to address this issue before continuing with any other maintenance or checks, as it can affect several components downstream, including filters, burners, and overall system performance.

This foundational step ensures that the system operates smoothly, reducing the likelihood of problems during operation and extending the lifespan of the equipment. Other checks, such as inspecting the thermostat, electrical connections, or insulation, are also important, but they would typically take place once the initial checks for potential water issues have been addressed to ensure a clean and safe working environment for the remaining maintenance tasks.