No, the GT250 does not utilize an air filter. Maintenance procedure requires cleaning dust and debris off heat sink. Inspect the intake air ducts and external cooling fans for accumulation of dirt and debris. Accumulation of dirt and debris within the duct and matrix cooling fans will decrease their ability to move air and thus transfer heat away from the IGBT matrix heatsink, which may cause the GT250 to enter a Fault state based upon an over-temperature alarm. Remove and clean if debris is present.