An appointing authority, from time to time, may suspend an employee without pay or other compensation as punishment for improper behavior, but no employee may be suspended for a period or periods within the aggregate of more that 30 days in any year‘s service. A suspension may be effected by serving written notice upon the employee together with a statement clearly setting forth the causes thereof; a copy of which shall be forthwith mailed or delivered to the director. The suspended employee may file with the board and the appointing authority a written answer or explanation of the assigned charges and such answer shall be preserved as a part of the public record and the board, for cause shown, may set aside such suspension order.