• Applicants may face competition for jobs; opportunities will be best for workers with training in computerized controls and instrumentation.
• Stationary engineers and boiler operators usually acquire their skills through a formal apprenticeship program, or on-the-job training supplemented by courses at a trade or technical school.
• Most States and cities have licensing requirements.

Heating, air-conditioning, refrigeration, and ventilation systems keep large buildings and other commercial facilities comfortable all year long. Industrial plants often have facilities to provide electrical power, steam, or other services. Stationary engineers and boiler operators operate and maintain these systems, which include boilers, air-conditioning and refrigeration equipment, diesel engines, turbines, generators, pumps, condensers, and compressors. The equipment that stationary engineers and boiler operators control is similar to equipment operated by locomotive or marine engineers, except that it is not in a moving vehicle.

Stationary engineers and boiler operators start up, regulate, repair, and shut down equipment. They ensure that the equipment operates safely, economically, and within established limits by monitoring meters, gauges, and computerized controls. Stationary engineers and boiler operators control equipment manually and, if necessary, make adjustments. They also record relevant events and facts concerning the operation and maintenance of the equipment in a log. With regard to steam boilers, for example, they observe, control, and record the steam pressure, temperature, water level, chemistry, power output, fuel consumption, and emissions from the vessel. They watch and listen to machinery and routinely check safety devices, identifying and correcting any trouble that develops. They use hand and power tools to perform repairs and maintenance ranging from a complete overhaul to replacing defective valves, gaskets, or bearings. Service, troubleshooting, repair, and monitoring of modern systems require the use of sophisticated electrical and electronic test equipment.

Stationary engineers typically use computers to operate the mechanical, electrical, and fire safety systems of new buildings and plants. Engineers monitor, adjust, and diagnose these systems from a central location, using a computer linked into the buildings' communications network.

Routine maintenance, such as lubricating moving parts, replacing filters, and removing soot and corrosion that can reduce the boiler's operating efficiency, is a regular part of the work of stationary engineers and boiler operators. They test the water in the boiler and add chemicals to prevent corrosion and harmful deposits. In most facilities, stationary engineers are responsible for the maintenance and balancing of air systems, as well as hydronic systems that heat or cool buildings by circulating fluid (as water or vapor) in a closed system of pipes. They also may check the air quality of the ventilation system and make adjustments to keep the operation of the boiler within mandated guidelines.

In a large building or industrial plant, a stationary engineer may be in charge of all mechanical systems in the building. Engineers may supervise the work of assistant stationary engineers, turbine operators, boiler tenders, and air-conditioning and refrigeration operators and mechanics. Most stationary engineers perform other maintenance duties, such as carpentry, plumbing, locksmithing, and electrical repairs. In a small building or industrial plant, there may be only one stationary engineer.