The effect of the operating temperature on the behavior of coal ash on ceramic filters in a hot gas filtration system was studied. It was found that when the operating temperature exceeds the sintering temperature of the ash generated during combustion, the chance of forming ash-bridges between these filters is high. Calcium and potassium aluminosilicate were found to initiate the sintering of these samples, which results in an increase in the compression strength of these samples by an order of magnitude.