HVAC final exam, unit 16 Completely Solved

A ___ reacts to stop, start, or modulate the flow of water, air, or refrigerant to the system or conditioned space - ANSWER Controlled device All control systems can be subdivided into ____, no matter how many controls there are. - ANSWER Control loops _______ control systems were used before electronics. - ANSWER Pneumatic Pneumatic controls must have a permanent air supply that is ______ - ANSWER clean and dry Most system compressors provide ______ psig of air pressure to the storage tank. - ANSWER 100 to 125 In most systems compressors, the compressors are controlled with a - ANSWER pressure switch A _______ is either in the pressure reducer or in the downstream side of the system to ensure that the control air pressure does not exceed about 30 psig. - ANSWER relief valve In a(n) ______ loop, all changes happen within the loop - ANSWER closed A device called a ______ is used to control the large volume of air in a air conditioning system. - ANSWER Pilot positioner The pilot positioner has a main air supply that is governed by the ______. - ANSWER internal diaphragm Controlling the water flow to the rooms need is called - ANSWER modulating flow The temperature in the room is known as the _____ air temperature - ANSWER ambient Electronic controls are commonly called ______. - ANSWER direct digital controls The controlled environment by an array of _______ such as dampers, fans, variable-frequency drivers. - ANSWER Controlled output devices __________, usually housed internally inside the controller, convert the information from either analog to digital (A/D) or digital to analog (D/A) format - ANSWER Signal converters T/F: The very first control system were used to start and stop the various components - ANSWER True T/F: Space temperature is the only temperature that is important in modern systems - ANSWER False