Install refrigeration systems Install ventilation, air handling and air conditioning systems Interpret blueprints or other instructions to plan methods or sequences of operation Measure and lay out reference points for installation Troubleshoot heating systems Troubleshoot ventilation, air handling, refrigeration and air conditioning systems Assemble and install refrigeration or air conditioning components Coach and instruct apprentices Start up system and test for leaks using testing devices Perform maintenance such as, recharging system with refrigerant, checking and testing regulators or calibrating system Repair and replace parts and components for entire refrigeration, air conditioning, ventilation or heat pump systems