What can excessive soot build-up in a furnace indicate?

Excessive soot build-up in a furnace typically indicates incomplete combustion, which often occurs due to an incorrect oil-air mixture. When the mixture is imbalanced, there is not enough air for the fuel being burned, leading to inefficient combustion. This results in soot production as the fuel doesn't fully burn and leaves behind carbon particles, which accumulate over time.

Monitoring the combustion process is crucial, as proper combustion should produce minimal soot. Maintenance practices often involve checking and adjusting the oil-air mixture to ensure that it stays within an optimal range, thereby promoting complete combustion and reducing soot formation. This understanding helps technicians to diagnose performance issues and maintain the efficiency and safety of heating systems.