53 Pa. Stat. § 23448
Third.--When the services to be rendered are of a temporary character and for a limited period, not to exceed six months, the appointing officer shall advise the commission, stating the duration of such period, the rate of compensation, and other conditions of employment, and may thereupon select for such temporary employment one of the first three persons on the appropriate eligible list who have expressed a willingness to accept a temporary appointment. Successive temporary appointments shall not be made under this clause; nor shall any person be eligible to temporary appointment if he has served under either a temporary or a provisional appointment, in the same office or department, within the previous six months. The acceptance or refusal, by an eligible, of a temporary appointment shall not affect his standing on the register for permanent employment, nor shall the period of temporary service be counted as a part of the probationary service in case of subsequent appointment to a permanent position. The acceptance of a temporary appointment shall not confer upon the eligible any of the rights of promotion, transfer, or reinstatement.
53 P.S. § 23448