53 Pa. Stat. § 23446
Every position or employment in the competitive class, unless filled by promotion, transfer, reinstatement, or reduction, shall be filled only in the following manner: The appointing officer shall notify the civil service commission of any vacancy in the service which he desires to fill, and shall request the certification of eligibles. The commission shall forthwith certify, from the appropriate eligible list, the names of the three persons thereon who received the highest averages at examinations held under the provisions of this act. The appointing officer shall, thereupon, with sole reference to the relative merit and fitness of the candidates, make an appointment from the three names so certified: Provided, however, That should he make objection, to the commission, to one or more of these persons, for any of the reasons stated in section ten of this act, and should such objections be sustained by the commission, the commission shall thereupon strike the name of such person from the eligible list, and certify the next highest name for each person so stricken off. As each subsequent vacancy occurs, in the same or a similar position, precisely the same procedure shall be followed: Provided, however, That after any name has been three times rejected, for the same or a similar position, in favor of a name or names below it on the same list, the said name shall be stricken from the list. When there are a number of positions of the same kind to be filled at the same time, each appointment shall, nevertheless, be made separately and in accordance with the foregoing provisions. When an appointment is made under the provisions of this section, it shall be, in the first instance, for the probationary period of three months, as provided in section eight of this act. The provisions of this section (fourteen) shall not apply in making appointments to competitive positions which are specially excepted by the commission from competitive examinations under the authority conferred in section fifteen.
53 P.S. § 23446