Abstract: In the boiler acid washing process, due to that the water quality in the case of boiler water recirculating pump does not satisfy the requirement; the cooling water in the shell of the motor is polluted easily; the filter screen for cooling water circulation is blocked and the cooling efficiency of the cooling water decreases. So, the temperature of the motor will rise rapidly, the boiler water pump will trip and the unit will shut down. Aiming at abovementioned problems, effective treatment and preventive measures were proposed, and the safety, the stability and the economic benefit of the unit were improved.

Key words: boiler water recirculating pump, acid washing, cooling, sundries, filter screen, accident analysis, prevention