Basic info
Maintenance
240216 replaced one bearing in fan motor. The fan was making a loud, low screech, especially at speed setting 1. The sound remained even with the housing panel and fan-blade cylinder removed, meaning the issue was likely in the motor itself. After unplugging the unit, I could remove and open the motor by... 1) releasing the motor/fan housing from the back panel (four torx screws) 2) removing the motor from the housing (four screws through rubber bushings) 3) and opening the motor by unscrewing the two long, stainless bolts that pass entirely through the motor. The rear bearing was entirely seized. I removed the bearing from the motor casting with a make-shift bearing puller: an M8 screw and a stack of large washers. The bearing is identical size to skateboard bearings I had on hand.
replacement filter: Bosch Charcoal / Carbon Filter KF250090
"replace when filter is noticeably dirty or discolored ( 4-6 months)"