How does the firing sequence affect furnace safety during start-up?

The firing sequence during furnace start-up is crucial for ensuring safety, especially regarding the risk of combustible gases accumulating within the furnace. A pre-purge period is an essential step that typically involves evacuating any residual gases from the combustion chamber before ignition occurs. This is important because it prevents the possibility of an explosion or harmful emissions that could result from igniting trapped gases.

Implementing a pre-purge helps establish a safe environment by ensuring that only the necessary fuel and air mixtures are present in the combustion chamber during ignition. This practice not only enhances safety but also supports efficient furnace operation by ensuring a clean burn once the ignition occurs. By including this step in the firing sequence, you minimize the risks associated with gas handling, which is a critical element of safe furnace operation.