What characterizes faulty venting in a combustion appliance?

Faulty venting in a combustion appliance occurs when the pressure in the vent is more positive than the pressure in the Combustion Appliance Zone (CAZ). This situation can lead to the improper venting of combustion gases, creating a risk for backdrafting.

In a properly functioning system, the vent should maintain pressure that encourages the movement of negative pressure in the CAZ to effectively direct combustion by-products away from the appliance. If the vent pressure surpasses that of the CAZ, it can force exhaust gases back into the living space instead of safely directing them outside, leading to dangerous conditions such as the accumulation of carbon monoxide.

Understanding the dynamics of pressure within the vent and CAZ is crucial for ensuring safety and efficacy in combustion appliances. This knowledge assists technicians and safety inspectors in identifying potential hazards related to venting systems.