Operate or tend stationary engines, boilers, and auxiliary equipment such as pumps, compressors, and air-conditioning equipment, to supply and maintain steam or heat for buildings, marine vessels, or pneumatic tools. Observe and interpret readings on gauges, meters, and charts registering various aspects of boiler operation to ensure that boilers are operating properly. Test boiler water quality or arrange for testing and take necessary corrective action, such as adding chemicals to prevent corrosion and harmful deposits. Activate valves to maintain required amounts of water in boilers, to adjust supplies of combustion air, and to control the flow of fuel into burners. Monitor boiler water, chemical, and fuel levels, and make adjustments to maintain required levels. Fire coal furnaces by hand or with stokers and gas- or oil-fed boilers, using automatic gas feeds or oil pumps. Monitor and inspect equipment, computer terminals, switches, valves, gauges, alarms, safety devices, and meters to detect leaks or malfunctions and to ensure that equipment is operating efficiently and safely. Analyze problems and take appropriate action to ensure continuous and reliable operation of equipment and systems. Maintain daily logs of operation, maintenance, and safety activities, including test results, instrument readings, and details of equipment malfunctions and maintenance work. Adjust controls and/or valves on equipment to provide power, and to regulate and set operations of system or industrial processes. Switch from automatic to manual controls and isolate equipment mechanically and electrically to allow for safe inspection and repair work. Clean and lubricate boilers and auxiliary equipment and make minor adjustments as needed, using hand tools. Check the air quality of ventilation systems and make adjustments to ensure compliance with mandated safety codes. Perform or arrange for repairs, such as complete overhauls, replacement of defective valves, gaskets, or bearings, or fabrication of new parts. Weigh, measure, and record fuel used. Develop operation, safety, and maintenance procedures or assist in their development. Install burners and auxiliary equipment, using hand tools. Contact equipment manufacturers or appropriate specialists when necessary to resolve equipment problems. Test electrical systems to determine voltages, using voltage meters. Provide assistance to plumbers in repairing or replacing water, sewer, or waste lines, and in daily maintenance activities.