Here  is a sample question you might expect on the Washington State Home Inspection Exam:

What is a likely reason for a gas furnace to shut down after firing up?

A) the filter is dirty
B) disconnected inducer fan
C) a tripped primary control
D) ignitor failure

If the filter is dirty, the furnace will have a reduction of airflow and may overheat. If it gets hot enough, it will trip the over-temperature safety switch and shut down.
Most furnaces will then cool off and reset and then restart, resulting in “short cycling”. This is very inefficient and will repeatedly overheat the furnace, likely reducing the furnace life.
All furnaces should have air filters and an overtemperature safety switch, making them vulnerable to this problem.  So if your furnace is “not quite keeping up” with the cold weather, it might be as simple as changing out the filter te get you back in the heat!

If you are interested in learning more be sure to take the Home Inspection Aptitude test.  Call us anytime we love to talk about home inspections.

JJ Greive

JJ & Suzanne are both licensed, highly skilled inspectors and educators. We are the authors of our class curriculum, and truly enjoy sharing this with our students