What is the over fire draft reading typically measured at?

The over fire draft reading is typically measured at a negative value, indicating that there is a slight pressure difference that helps control the combustion process in oil-burning equipment. A reading of -0.02 inches of water column is standard for over fire draft in many situations.

This reading signifies that there is a negative pressure in the flue gas path, which assists in the efficient removal of combustion gases and ensures proper inhalation of air into the combustion chamber for a complete burn. Maintaining this negative draft is critical in establishing a balanced system, ensuring that gases are expelled correctly while air is drawn in appropriately.

Other values, such as 0.00 or positive figures like 0.05, would imply a lack of suction or an excess of pressure, which can lead to inefficiencies in combustion and potential safety concerns. Therefore, the measurement of -0.02 is aligned with best practices in oil combustion to facilitate optimal operation.