This book was written specifically for boiler plan operators and supervisors who want to learn how to lower plant operating costs, as well as how to operate plants of all types and sizes more wisely. It is newly revised with guidelines for HRSGs, combined cycle systems, and environmental effects of boiler operation. Also included is a new chapter on refrigeration systems that addresses the environmental effects of inadvertent and intentional discharges of refrigerants. Going beyond the basics of "keeping the pressure up," the author explains in clear terms how to set effective priorities to ensure optimal plant operation, including ensuring safety and continuity of operations, preventing damage, managing environmental impact, training replacement plant operators, logging and preserving historical data, and operating the plant economically.