How does a category 2 venting system operate in relation to flue gas dew point temperature?

A category 2 venting system is designed to operate with flue gases that have a temperature lower than the acid dew point. Specifically, the flue gas temperature in a category 2 system is typically maintained at less than 140° F. This design helps to avoid condensation of acidic combustion byproducts, which can lead to corrosion of the venting materials and system components.

By keeping the temperature below 140° F, the system ensures that the flue gases remain above their dew point, preventing condensation from occurring inside the vent. This is crucial for maintaining the integrity and longevity of the venting apparatus and ensuring that exhaust gases are safely and effectively expelled from the heating appliance.

In contrast, temperatures at or above 140° F may lead to situations where condensation can occur if the flue gas temperature drops, increasing the likelihood of damage over time. Therefore, maintaining operation below this temperature is a critical aspect of ensuring the performance and safety of category 2 venting systems.