What happens if a vacuum gets too hot?
The vacuum needs a certain amount of air to keep it from overheating. The tolerances of the rotors are measured in 10,000’s of an inch. If the air flow is blocked, the rotors will overheat and eventually expand to a point where they contact the sides of the housing. When this happens, serious damage will result. If the rotors actually touch the sides of the housing, they may lock up without warning and twist off the drive shaft. At this point the vacuum is scrap and cannot be repaired. This damage happens to many contractors who have never used PD blowers before. After they replace one $20,000 blower, they will understand how critical cooling is to a vacuum.
