To eliminate the danger of a furnace explosion during start-up, the firing sequence must first allow for what?

To ensure safety during the start-up of a furnace and eliminate the danger of an explosion, a pre-purge period is essential. This step involves clearing any residual fuel or combustible gases from the combustion chamber and associated piping before introducing fuel or igniting the burner.

During this pre-purge period, the blower is typically activated to ventilate the furnace and create a safe environment. By ensuring that any flammable materials are removed, the risk of a dangerous explosion during start-up is significantly reduced. Properly following this step allows the system to operate safely and effectively when it is time to ignite the fuel.

Implementing a pre-purge is critical, as it establishes the foundation for a safe combustion environment, ensuring that there are no accumulations of flammable gases that could ignite unexpectedly. This practice is a standard safety procedure in the operation of high-pressure boilers and furnaces.