Assist with operation, maintenance and repair of refrigerant compressors, condensers, evaporators, traps, transfer pumps, expansion valves, stop valves and float valves, together with all refrigerant lines and devices used to control temperature, and air conditioning systems in their entirety, including the use of approved recovery equipment and processes to comply with the law. Assist with operation, maintenance and repair of water filters, softeners, piping, expansion tanks, and pumps used in conjunction with water distribution, including all sinks and toilet bowls, including all supply lines, drains, water lines, control devices and sprinkler systems.