They hand fire high pressure boilers using solid fuels, and stoker equipment and incinerator furnaces using burnable refuse; clean fires; tend and operate stoker equipment, oil, gas, or coal fired high pressure boilers and incinerator furnaces, and related equipment; maintain, clean, repair and assist in the inspection and testing of high pressure boilers, incinerators, auxiliaries and related equipment; maintain, clean, repair and/or tend to, and assist in the inspection and testing of equipment and systems used in heating, ventilation, refrigeration, air conditioning and related auxiliary equipment, such as cooling towers, air handlers, chilled water pumps, air cleaners and filters, fans, heat exchangers, tubes, air treatment assemblies, humidifiers/dehumidifiers, and controls; may dismantle and/or assemble equipment associated with heating, ventilation, refrigeration, air conditioning and mechanical systems to make it operational; requisition parts as required; and may operate a motor vehicle. Some of the physical activities performed by High Pressure Plant Tenders and environmental conditions experienced are: climbing stairs, ladders and over boiler room equipment; standing upright for extended periods of time; using vision to read small numbers and markings on gauges and equipment; using vision and hearing to avoid injury from overhead piping and rotating machinery; communicating orally in a noisy working environment; walking over wet and slippery concrete surfaces; working in areas containing gases from the combustion process and strong odors from grease, lubricants and solvents; working in confined areas inside boilers and under piping which may be dusty and dark; lifting metal objects weighing up to 60 pounds; and working with alkaline and acidic chemicals used in boiler water treatment.