Very loud banging in steam heat pipes and "wind vibrations." A year ago we replaced the two oil burning furnaces with newer, smaller furnaces with the tankless hotwater. (Two family house, built 1900. we got off the gas hot water heaters). Shortly after ( 4 to 6 months) a banging began when the heat came on. It got louder and louder and now is extremely loud. The company who installed has no answers for us! The banging is way too loud for this to be normal. Suggestions please!!