Operates, maintains, and repairs boilers, heaters, pumps, valves, appurtenances, and lines used in the distribution of steam and heated or processed water; operates, repairs and maintains refrigerant compressors, condensers, evaporators, traps, transfer pumps, expansion valves, stop valves, and float valves, together with all refrigerant lines and devices used to control temperatures; operates, maintains and repairs air compressors, together with distribution lines and all valves and devices for air control; operates, maintains and repairs all natural and manufactured gas distribution lines, including all valves and control devices; operates, repairs, and maintains water filters, softeners, piping and pumps used in conjunction with water distribution, including all sinks and toilet bowls, supply lines and water lines; operates, repairs and maintains all types of motors and engines used to power pumps, compressors and fans; repairs and maintains single phase and multiphase electrical circuits up to 550 volts; repairs and maintains electrical transformers, motors, controls, machinery, fixtures, appliances and elevators; repairs and maintains electronic systems such as clocks, closed circuit television, automatic alarm systems, security systems, energy management systems, equal potential grounding and automatic power transfers; calibrates control systems, including air balance, humidistats and solid state electronic motor control amplifiers; operates, maintains and repairs water and sewage systems, laundry and culinary equipment; inspects and trouble shoots electrical and mechanical systems and equipment to identify repairs needed; performs minor building maintenance and repair; plans, layouts and estimates costs of electrical; mechanical, and electronic systems; requisitions parts, supplies and equipment; calculates systems requirements to provide estimates for modification or replacement of systems; and when assigned, maintains order and supervises the conduct of persons committed to the Department of Corrections and the Youth Authority; prevents escapes and injury by these persons to themselves or others or to property; maintains security of working areas and work materials; inspects premises and searches incarcerated persons, wards, residents, or patients for contraband such as weapons or illegal drugs; leads and trains subordinate and less senior personnel, and advises them of unusual problems, procedures, and practices. Under general direction, to perform a variety of skilled work in the operation, maintenance and repair of boiler, heating, air conditioning, ventilating, lighting, power, water, water treatment, and other mechanical systems normally found in a State correctional facility in the Department of Corrections or Department of the Youth Authority; to maintain order and supervise the conduct of incarcerated persons, wards, residents, or patients and protect and maintain the safety of persons and property; may instruct or lead incarcerated persons, wards, patients, or resident workers; may instruct or lead other engineers; and do other related work.