My Stelrad Ideal W-2000 boiler flue fan failed in December. I diagnosed the fault to a failed bearing, which jammed the K3-12-034.168 electric motor. A pair of new 626-Z (6mm x 19mm x 6mm) bearings cost just £1.92, considerably less than a refurbished fan assembly (which, incidentally, is no longer manufactured).
Lost Distance
February 2008