What must be conducted during an annual tune-up on a heating system?

During an annual tune-up of a heating system, conducting a combustion efficiency test is essential. This test measures how effectively the heating system converts fuel into usable heat and identifies any issues that may reduce performance or increase emissions. By assessing combustion efficiency, technicians can ensure that the system operates safely and efficiently, leading to better energy use and reduced operational costs.

Addressing combustion efficiency is integral to maintaining safety and compliance with applicable codes, as improper combustion can produce hazardous gases, including carbon monoxide. This makes the test a critical component of a comprehensive annual maintenance routine, helping to identify necessary adjustments or repairs before they lead to more significant problems.

In contrast, the other options do not represent the standard practices required during a tune-up. A full system replacement is unnecessary and not part of routine maintenance unless the system is beyond repair. A pest inspection, while potentially important in some contexts, is not a standard procedure during a heating system tune-up. Finally, a visual inspection only would not be sufficient, as it does not include the critical measurements needed to ensure combustion efficiency.