Below is an additional breakdown of what you can expect day to day: Preventative Maintenance: When dispatched for routine maintenance visits, you inspect machines, clean components and condenser coils, replace filters as needed, check refrigerant pressures, superheat, and subcooling, inspect electrical connections and components, and ensure units are operating optimally. That can mean anything from leak detection, brazing, and compressor swaps to refrigerant recovery, evacuation, and charging, replacing filter driers and metering devices, or troubleshooting fan motors, capacitors, contactors, relays, control boards (MCU), and sensors.