Stationary engineers operate and maintain large heating and ventilation systems such as steam engines and boilers.

Engineers operate engines, boilers, and generators. They check meters, gauges, and computerized controls. They monitor water, chemical, and fuel levels and make adjustments as necessary.

Stationary engineers also maintain and repair equipment. They inspect equipment to make sure it is running efficiently. They lubricate parts and replace filters. They test boiler water and add chemicals to stop harmful deposits. They use hand and power tools when making repairs.

Engineers regularly check safety devices and monitor air quality.

Stationary engineers keep records of breakdowns, repairs, fuel used, and other information about the equipment.

In large buildings, stationary engineers may be in charge of all mechanical systems. They sometimes use computers or manual controls to monitor some of these systems. They may also supervise workers, such as assistant boiler engineers and boiler tenders. Some engineers do carpentry, plumbing, and electrical repairs.