Troubleshoot, repair or replace defective parts in units and equipment and their controls, including thermostats, automatic switches, fan controls, log switches, damper motors, louvers, relays, filters, controls, belts, compressors, heat exchanges, high limit controls, pressure controls and safety valves. Inspect, repair, modify and install HVAC equipment including refrigeration and air conditioning compressors, receivers, condensers, forced air converter units, and make necessary adjustments or repairs, service and repair evaporative coolers.