Work requires knowledge of refrigeration and air conditioning, mechanical, electrical and electronic theory and equipment, gas-fired and steam boilers, control wiring, pneumatic controls (including their operation and how to troubleshoot them), safety codes, practices and regulations, HVAC BAS systems, ability to read blueprints and schematics, calculate heat and air conditioning loads, pipe sizes and pressures, and interpret chemical test results - acquired through 1 to 4 years of technical training in an apprenticeship, vocational, or community college program following completion of high school. Work requires level of knowledge of the operation, repair and the installation of a wide variety of complex mechanical and related equipment and applicable codes, and the ability to coordinate major jobs and repair work involving skilled workers - acquired through 2 years’ progressively more responsible related experience .