PURPOSE: To prevent drain from staying in a drainpan by providing a drainpan which is incliend in one direction and freely slidable in the direction of extension from a main body.

CONSTITUTION: A drain pan 22 which has a grade 23 is provided with metallic fixtures 24, 25, 34, and 35 with right side fixing holes 24a, 25a, 34a, and 35a and left side fixing holes 24b, 25b, 34b, and 35b. Water drain holes provided at both ends of the deepest section of the drainpan 22 are connected to a drain hose 27. When one of the drain holes is used, the other is closed with a blind lid. Since the metallic fixture 24 and 25 are symmetrical with respect to the metallic fixtures on the rear face side, the drain holes 26 can be brought either to the front face side or the rear face side, and the one which is convenient for connection with the drain hose 27 is selected. In either of the right piping or the left piping a valve 32 has a drainpan 22 below it and it can receive condensation dew developed at a place where heat insulation is difficult.