I searched youtube to find ways to check heat exchangers for cracks that can leak carbon monoxide into living spaces. Found furnace checks by "The DIY HVAC Guy" and ran through these checks on my furnace. The main points are cleaning blower wheel and motor, and blower compartment, pulling burner jets and tubes and cleaning jets, cleaning flame sensor, and checking exchangers for leaks. It also goes into testing of other components and checking them with a fancy multimeter. It also talks about setting the gas pressure on the gas valve to a setting according to your elevation. That requires buying a manometer.

It could be valuable if you just wonder what's in a furnace, to help interface with an HVAC service person, or if you are a serious doityourselfer.

Here is the main video: https://www.youtube.com/watch?v=EJsSRLo0Plg

CO detectors are cheap, always keep one around the heater.

quote:

Originally posted by mrvmax:
CO detectors are cheap, always keep one around the heater.

Bought one yesterday