When Im having oil delivered, Ive noticed a whistling sound while the tank is filling. What is that?
The whistle is a safety feature of your oil tank. When the deliveryman fills your tank, the oil displaces air, which leaves the tank through a separate vent. As the air escapes, it passes a device that whistles, just like a tea kettle. When the fill is complete, there is almost no air left and the whistler device quiets.The silence indicates that the tank is full.
