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).
2 wire thermostat. A 2 wire thermostat is connected between line and the switched line terminal on the boiler. When heat is required, the thermostat connects these two wires together, applying the full mains voltage to the switched line terminal. This activates the boiler.