If an inspection of the filter shows a build-up of dirt or debris on the filter, it should be cleaned. The filter can be vacuumed to remove the build-up. Visually inspect the flame arrester by placing a mirror underneath the water heater. A flashlight can be used to illuminate the slots in the flame arrester if necessary. Routine cleaning of the flame arrester is recommended if the inspection shows accumulation of debris on the flame arrester.
Use a vacuum cleaner to remove all loose debris in the flame arrester. If necessary, a soft bristle brush can be used to dislodge any remaining debris.