Chapter 4 — Control Principles Chapter 4 Control Principles Control System Components Sensors Controllers Controlled Devices Control Agents Control Functions Control System Characteristics Closed Loop Control Open Loop Control ON/OFF Control Proportional Control Control System Requirements

Chapter 4 — Control Principles Competencies List and describe common HVAC control system components. Compare common control system components found in heating, cooling, humidification, and ventilation systems. List and describe common methods used to control temperature, humidity, and pressure. Identify common control system characteristics. Describe common control system arrangements. Identify common control system requirements. List and describe common HVAC control system components. Compare common control system components found in heating, cooling, humidification, and ventilation systems. List and describe common methods used to control temperature, humidity, and pressure. Identify common control system characteristics. Describe common control system arrangements. Identify common control system requirements.

Chapter 4 — Control Principles HVAC control system components sensor controller controlled device control agent

Chapter 4 — Control Principles Comparison of HVAC control system components Heating systems hot water, steam, electric heating elements, or combustion Cooling systems chilled water, direct expansion cooling or outside air Humidification low-pressure steam, hot water vapor Heating systems hot water, steam, electric heating elements, or combustion Cooling systems chilled water, direct expansion cooling or outside air Humidification low-pressure steam, hot water vapor

Chapter 4 — Control Principles Controlling temperature, pressure, and humidity room controller or thermostat return air sensor or controller safety controls humidity sensor or controller pressure sensor room controller or thermostat return air sensor or controller safety controls humidity sensor or controller pressure sensor

Chapter 4 — Control Principles Control system characteristics setpoint control point offset feedback

Chapter 4 — Control Principles Control system arrangements closed loop open loop ON/OFF proportional (analog)

Chapter 4 — Control Principles Control system requirements provides safe, automatic and accurate regulation of environmental conditions poses no immediate risk to building occupant health operates automatically accuracy is measured and provided to the customer provides safe, automatic and accurate regulation of environmental conditions poses no immediate risk to building occupant health operates automatically accuracy is measured and provided to the customer

Chapter 4 — Control Principles Chapter 4 Review What is the function of a controller? to compare a signal to a setpoint value and send an appropriate output signal What is open loop control? no feedback occurring between the controller, sensor, and controlled device What is the function of a controller? to compare a signal to a setpoint value and send an appropriate output signal What is open loop control? no feedback occurring between the controller, sensor, and controlled device