Pro Tip: Avoid time-consuming oven maintenance issues by keeping filters clean and sealed tight in the housing.
At the heart of every natural gas oven are the burners that are fed clean air by the combustion air blower. If that air is dirty, which is more than likely if it’s drawn from the inside of your bakery, the burners and mixer valves will eventually get clogged with dust and dirt.
There are three main issues with combustion air filters:
Clogged filter: This is most common on blowers that draw their air supply from inside the bakery, where flour and other product dust often fills the air during production and settles on top of the oven. If this is a constant battle, consider running ductwork to draw your combustion air supply from outside the bakery where the air is already cleaner. If you can’t see light shining through the filter, it needs cleaning or replacing.
Bad seal: Even a HEPA filter is pointless if dust can squeeze between the filter and the housing. Remove the filter and examine the edges of the housing. Dust tends to collect near the spot where it is slipping past the filter. Consider applying adhesive foam strips or weatherstripping to seal the gap.
No filter: This is usually found on large indirect fire burners or ovens that have a small blower for each individual burner. Virtually all natural gas burners will benefit from having a clean air supply. Just because it was installed without a filter and has run that way for years doesn’t mean it belongs that way.
Remove the combustion blower filter and look in the intake. If there’s dust and dirt in there, you can bet it’s collecting in other places, such as inside the burner ribbon on a direct natural gas fired oven. Tap on a burner while observing the flame, and you’ll likely see a blue flame turn red with sparks as you knock dust loose inside the burner. This dust tends to carbonize where the ignitor arcs to the ribbon, making it more difficult to light the burner and further reducing heating capacity.
Cleaning burners is no easy task. The mixer valves can be removed and the venturis cleaned, but the dust that collects inside the burner ribbons is much more difficult to remove. Carbonized buildup on the ribbon is nearly impossible to remove without a chemical bath. Your best bet is to keep your burner air supply clean by ensuring your filters are clean and sealed tight in the housing.
Remember to clean or change your combustion air filters often to prolong oven performance and put off costly maintenance.
Mitch Brixey is manager of inspection services at Brixey Engineering Inc. He inspects more than 100 bakery ovens every year, often finding issues that would otherwise cause dangerous and expensive problems.
You can connect with him on LinkedIn.