Operation & Maintenance of Centralized Screw Chiller  units including pumps & VFD's Split/Package air- conditioners cleaning of filters,   checking of wiring and plugs, testing of machine for   proper operation and signs of wear & tear, regular checking & periodic cleaning of air side  equipment and ventilation fans etc., checking of fire dampers in ventilation ducts  will be  checked on regular basis by in- house team    Preventive maintenance checks which are not under the   AMC for AC plant Maintenance.