PURPOSE: To enable a forced draining to be easily performed on the ground without entering a ceiling by an operator by a method wherein a manual valve is arranged in the midway of a drain pipe, drain water is accumulated, another manual valve is arranged at a side, a vacuum facility is connected thereto, an interior of the pipe is changed forcibly into a vacuum state and then dusts and drain water are sucked.

CONSTITUTION: Under a normal operation, a manual valve 4 is opened and another manual valve 5 is closed. Drain water is naturally discharged in a descending gradient. As dusts are accumulated, the manual valve 4 is forcedly closed and the manual valve 5 is opened, a vacuum facility 6 is operated so as to clean drain water and dust in a fan coil. Accordingly, it becomes possible to make a forced draining of leaked drain water in a ceiling fan coil in advance and then it is not necessary to climb into the ceiling to check the water leakage to perform a respective check-up of component elements and a cleaning opera tion.