[lbarnes63]

While helping a friend replace the main fan motor of his gas furnace, I noticed that the inducer fan was turning the wrong direction. The unit had been operating like this for approx 6 years. we switched the wires, and the fan ran in the correct direction (verified by checking the airflow at the flue). what are the issues with this condition? was it pushing the exhaust into the house? are their efficiency issues? how could it have operated all this time with that condition?
thanks!