Our water heater burners, made of sheet metal construction, do not have a shutter for air adjustment.
Our water heaters equipped with a cast iron burner feature an air shutter to obtain the best mixture of gas and air for combustion purposes. In accordance with the instructions, the shutter is to be adjusted at the time of installation. It should also be checked at periodic intervals of six months to determine that the burner is performing properly.
To adjust for proper burning with the new spring style air shutter, slowly rotate the shutter until the yellow tips disappear and the flame becomes blue. With the old style, loosen the air shutter lock nut and then rotate the shutter. Tighten the air shutter lock nut when completed.
Too much air will cause the flame to lift off the burner ports and create noisy operation. Too little air will result in soot formation.
The 65 port cast iron is presently used on 30, 40, 50, 65, 75, and 100 gallon propane models and special natural gas models.