Corrosion in a flue pipe is likely to occur when the flue gas temperature is what?

Corrosion in a flue pipe occurs more readily when the flue gas temperature is below the dew point. At this temperature, flue gases condense, creating moisture within the flue pipe. This condensation can lead to the formation of acidic substances, particularly when sulfur dioxide and water vapor combine, which is a common result of burning oil. These acids, when combined with the heat exchanger surfaces or the flue pipe materials, can rapidly increase the rate of corrosion.

When the temperature is above the dew point, the flue gases remain in a vapor state, preventing condensation and minimizing moisture-related corrosion. Maintaining flue gas temperatures above the dew point is essential in preventing this type of corrosion, extending the lifespan of the flue system, and ensuring efficient operation. Therefore, if the flue gas temperature is consistently below the dew point, it increases the likelihood of moisture accumulation and consequent corrosive damage.