All rights reserved. Printed in the United States of America. Page 4 a word that matches the picture (Listening Comprehension standard score = 84) and generate words within a category, describe scenes, and give directions (Oral Expression standard score = 83).
The power is supplied by a transformer, and when the thermostat makes contact between the 24 volt power and one or two of the other wires, a relay back at the heating/cooling unit activates the corresponding heat/fan/cool function of the unit(s).
A thermostat is part of the cooling system that regulates the temperature of the coolant in the engine. The thermostat is a metal valve that has a temperature sensor built in. It can either be open or closed. When the thermostat is closed, it keeps the coolant in the engine. When the engine gets to a predetermined temperature, the thermostat opens allowing coolant to circulate. The circulation of coolant prevents the engine from overheating. If the thermostat fails to open, the car will overheat.