Which of the following is a common cause of excessive flame rollout in a gas appliance?

Excessive flame rollout in a gas appliance typically indicates that combustion gases are not being properly vented away from the burner area, which can lead to unsafe operating conditions. A blocked venting system is a common cause of this issue, as it prevents the necessary exhaust of combustion gases, resulting in flames rolling out of the burners and potentially damaging the appliance or creating a fire hazard.

In a properly functioning gas appliance, efficient venting allows for the safe distribution of combustion byproducts, but when the venting is obstructed, it creates a scenario where the flames can escape the intended combustion chamber. This makes recognizing and correcting venting problems critical for ensuring safety and efficiency in gas appliances.

While other factors like low gas pressure, high ambient temperatures, and a defective blower motor can impact appliance performance, they do not typically lead to flame rollout directly in the same way that a blocked venting system can. Proper venting is essential for maintaining safe operation in gas-fired appliances, underscoring the importance of regular maintenance and inspection of the venting components.