1 Pa. Code § 35.162
The presiding officer, subject to § 35.190 (relating to appeals to agency head from rulings of presiding officers), shall rule on the admissibility of evidence, and shall otherwise control the reception of evidence so as to confine it to the issues in the proceeding. The number of expert witnesses to be heard on an issue may be limited appropriately as provided in § 35.127 (relating to limiting number of witnesses), or the production of further evidence upon any issue may be called for, as provided in § 35.128 (relating to additional evidence).
1 Pa. Code § 35.162
This section cited in 4 Pa. Code §89.29 (relating to evidence); 4 Pa. Code §265.3 (relating to level II hearings); 7 Pa. Code §131.33 (relating to evidence); 7 Pa. Code §179.61 (relating to hearing procedure); 10 Pa. Code § 3.11 (relating to hearing rules); 12 Pa. Code §81.209 (relating to rules of evidence not to apply); 25 Pa. Code §1021.123 (relating to evidence); 28 Pa. Code § 301.7 (relating to fair hearing); 34 Pa. Code §131.42 (relating to evidence relating to supersedeas); 34 Pa. Code §131.49 (relating to disposition of automatic request for special supersedeas under section 413(a.1) of the act (77 P. S. § 774(1)); 34 Pa. Code §131.50a (relating to employee request for special supersedeas hearing under section 413(c) and (d) of the act); 34 Pa. Code §131.53 (relating to procedures subsequent to the first hearing); 34 Pa. Code §131.53a (relating to consolidated hearing procedure); 34 Pa. Code §131.61 (relating to exchange of information); 34 Pa. Code §131.63 (relating to time for taking oral depositions); 34 Pa. Code §131.66 (relating to admissibility of oral depositions); 34 Pa. Code §131.203 (relating to hearing procedures); 34 Pa. Code §131.204 (relating to UEGF subpoenas and interrogatories); 37 Pa. Code §21.55 (relating to evidence); 40 Pa. Code §15.51 (relating to evidence); 52 Pa. Code §5.402 (relating to admission of evidence); 52 Pa. Code §5.403 (relating to control of receipt of evidence); 52 Pa. Code §1005.142 (relating to admission of evidence); 52 Pa. Code §1005.143 (relating to control of receipt of evidence); and 61 Pa. Code §702.6 (relating to formal rules of evidence).