Precipitators and baghouses are two systems designed to remove fly ash from boiler flue gas. Air pollution control regulations require that these precipitators and baghouses operate efficiently and reliably. Malfunctions or equipment failures could lead to boiler de-rating or complete shutdown, which increase the operation and maintenance expenses for the operating company. Problems related to fly ash collection in the hoppers, such as fly ash agglomeration and fly ash solidification, can lead to precipitator and baghouse shutdowns. The proper design and installation of hopper heating systems can significantly reduce the maintenance problems associated with fly ash plugging in hoppers.