Heating Systems

Question 1

Shuts off fuel if not enough airflow to carry heat out

Or if duct temp reaches its maximum?

Answer 1

Duct Limit Switch

Question 2

Set much higher than Duct switch but below fire hazard

and Shuts off combustion airflow, fuel supply, & ignition.

Answer 2

Overheat Switch

Question 3

Purpose of Canadian AD CF 90 03R2

Answer 3

To check for cracks and leaks in the exhaust system to prevent carbon monoxide from entering the cabin.