CC-TAIN11
控制回路分类说明通风基本协调室外、回风和排气挡板的操作，以保持适当的通风量。通常需要低温保护。更好地测量和控制室外空气量，以在不同的室内条件下提供室外空气和回风的适当混合（在可变风量系统中至关重要）。可能需要低温保护。冷却冷却器控制将冷却器排放水保持在预设温度或根据需要重置温度。冷却塔控制装置控制冷却塔风机，以在现有湿球温度条件下提供冷的水。水盘管控制调节冷冻水流量以保持温度。直接膨胀（DX）系统控制循环压缩机或DX线圈电磁阀以保持温度。如果压缩机为卸载式，则根据需要卸载气缸以保持温度。Fan Basic在占用期间开启送风机和回风机，并在空闲期间根据需要进行循环。更好地调整风扇体积，以保持适当的管道和空间压力。降低系统运行成本并提高性能（对于可变风量系统至关重要）。加热盘管控制调节水或蒸汽流量或电热以保持温度。锅炉控制操作燃烧器，以保持适当的排放蒸汽压力或水温。为了使热水系统达到大效率，应根据需求或室外温度重置水温。

Control Loop Classification Description Ventilation Basic Coordinates operation of the outdoor, return, and exhaust air dampers to maintain the proper amount of ventilation air. Low-temperature protection is often required. Better Measures and controls the volume of outdoor air to provide the proper mix of outdoor and return air under varying indoor conditions (essential in variable air volume systems). Low-temperature protection may be required. Cooling Chiller control Maintains chiller discharge water at preset temperature or resets temperature according to demand. Cooling tower control Controls cooling tower fans to provide the coolest water practical under existing wet bulb temperature conditions. Water coil control Adjusts chilled water flow to maintain temperature. Direct expansion (DX) system control Cycles compressor or DX coil solenoid valves to maintain temperature. If compressor is unloading type, cylinders are unloaded as required to maintain temperature. Fan Basic Turns on supply and return fans during occupied periods and cycles them as required during unoccupied periods. Better Adjusts fan volumes to maintain proper duct and space pressures. Reduces system operating cost and improves performance (essential for variable air volume systems). Heating Coil control Adjusts water or steam flow or electric heat to maintain temperature. Boiler control Operates burner to maintain proper discharge steam pressure or water temperature. For maximum efficiency in a hot water system, water temperature should be reset as a function of demand or outdoor temperature.