Maintain auxiliary equipment such as motors, pumps, fans, pipe systems, compressors, humidifiers, condensers and pneumatic and electronic control units; adhere to established maintenance schedules to replace filters, lubricate motors and fans, replace belts, conduct chemical analysis and add correct proportion of treatment chemicals, and cleaning other mechanical equipment located throughout a facility. Troubleshoot electrical circuits associated with heating, air conditioning and refrigeration including tracing dead circuits, rewiring circuits, repairing or replacing electrical components such as starters, contactors, relays and control units; repair or replace burner gun assemblies; recover refrigerant and recharge refrigeration equipment.