Section 341A.8 - Bases of appointments and promotions1. All appointments to and promotions to classified civil service positions in the office of county sheriff shall be made solely on merit, efficiency, and fitness, which shall be ascertained by open competitive examinations and impartial investigations, and no person in the classified civil service shall be reinstated in or transferred, suspended, or discharged from any such place, position, or employment contrary to the provisions of this chapter.2. Whenever possible, vacancies shall be filled by promotion. Promotion shall be made from among deputy sheriffs qualified by competitive examination, training, and experience to fill the vacancies and whose length of service entitles them to consideration. The commission shall for the purpose of certifying to the sheriff the list of deputy sheriffs eligible for promotion, rate the qualified deputy sheriffs on the basis of their service record, experience in the work, seniority, and military service ratings. Seniority shall be controlling only when other factors are equal. The names of not more than the ten highest on the list of ratings shall be certified. The certified eligible list for promotion shall hold preference for promotion until the beginning of a new examination, but in no case shall such preference continue longer than two years following the date of certification, after which said list shall be canceled and no promotion to such grade shall be made until a new list has been certified eligible for promotion. The sheriff shall appoint one of the ten certified persons.