08-14: Fan Stall Problems; Cause or Effect

The occurance of fan stall appears to be a common factor in an increasing number of cooling tower thermal performance problems. Frequently such problems arise following well intentioned but ill-advised retrofits. Because fan stall is not readily detected, it is often overlooked as a possible sole cause or contributor to performance problems, or as a symptom of other physical or mechanical problems. The mechanism and characteristics of fan stall and discussed in some detail together with detection methods enabling defective cells to be identified and targeted for prioritized repair.