In which category of vented appliances is excess condensate a known issue?

In vented appliances, excess condensate is primarily associated with Category 2 appliances. These appliances can operate with a non-positive vent pressure, meaning they often produce water vapor as a byproduct of combustion. When this vapor cools in the venting system, it can condense back into liquid water, leading to the accumulation of excess condensate. This is a concern because if the condensate is not properly managed, it can cause corrosion and other damages to the venting system and appliance itself.

Category 1 appliances also produce water vapor, but they typically use a positive vent pressure which helps to minimize condensation issues. Category 3 appliances are designed to use category-specific venting solutions that mitigate the risk of condensate, and Category 4 appliances employ high-efficiency designs that additionally combat condensation problems. Therefore, it is important to highlight that Category 2 appliances specifically face challenges with excess condensate due to their operational characteristics, making them distinct from the other categories.