Had a 19DH Chiller slugged with extremely high temperature chilled water (long story) popped the rupture disc and dumped the charge. Okay figured out the cause, replaced the rupture disc, did a complete evac. and add charge. Now the Chiller is surging hard! Condenser pressure 8 to 10, Refer pressure -10, condenser water good, CWS & CWR psi good. Before I tear it apart any suggestions?