A water heater draft hood plays an important role in the operation of a gas-fired water heater, as well as maintaining a safe environment for the homes occupants. The hood sits on legs at the top of the water heater where the combustion gases exit the tank. It connects to the vent that carries the exhaust out of the house.
The openings under the draft hood allow ambient air to be drawn into the vent to relieve pressure at the burner. As the hot gases rise out of the middle of the tank, the gas mixes with air and it is all carried up through the vent and out of the home. It also prevents a strong down-draft from extinguishing the burner or pilot.
Draft hoods have small tabs on their legs that slide into grooves at the top of the water heater. It’s common that one of the legs will have a screw hole to hold the legs of the diverter in place. Where the top of the diverter connects to the vent, it must be connected with a minimum of three screws. There really isn’t any maintenance on a draft hood, unless you have had some roofing work done around the vent. Then it might be a good idea to check the vent and draft hood to make sure there are no separations.Shower Door Hits on Bottom Frame » « Plumbing Straps Secure Piping to Walls