Explain what a limit switch is, as well as its function and how ...

[humphriesbr@me.com]

Explain what a limit switch is, as well as its function and how it affects the control circuit.
 
  What will be an ideal response?

Question 2

What is the relationship between electrical conductivity and thermal conductivity?
 
  What will be an ideal response?

[catron30]

Answer to Question 1

The limit switch is a safety control. It prevents the furnace from overheating. As long as the plenum chamber temperature is below the setting of the limit switch, the switch remains closed. If the plenum chamber temperature rises to the switch setting, it opens to de-energize the entire 24 V circuit and close the automatic gas valve.

Answer to Question 2

Materials that make good electrical conductors also tend to make good thermal conductors.