The county manager, in a county which has adopted either of the appointed forms of county managership, shall be appointed by the board of county commissioners. The county manager shall be appointed with regard to merit only and need not be a resident of the county at the time of appointment. No member of the board shall be chosen county manager during the time for which the member is elected nor shall the managerial powers be given to a person who at the same time is filling an elective office. The manager shall not be appointed for a definite tenure but shall be removable at the pleasure of the board. The county manager shall devote full time to county manager work. The county manager’s compensation shall be fixed by the board. In the absence or disability of the manager, the board may designate some responsible person to perform the duties of the office.