Getting to hard-to-access places

Sometimes, it seems that some engineers are woefully unable to think straight and place elements that need to be regularly tuned or replaced in all but accessible spots. 

They just drop them where it’s convenient to them, hoping the users will find a way to get it. 

We get our heat from a natural gas furnace and while it works very well, we need to pay attention to its flame sensor, a key safety element. During ignition, the gas gets ignited and the flame sensor rod generates a slight electrical current (in micro amps). 

If the furnace’s control board can’t read that current, the furnace will securely stop. Over time, the stainless steel rod will get soiled or build up carbon that must be cleaned. 

This is what I tried to do the other day when I realized that the small ¼” screw holding the heat sensor was extremely hard to reach and that prompted me to look for a solution, which was far from obvious since the small screw could be lost too easily inside the furnace underbelly before I simply could remove it or replace it. 

Tomorrow, I’ll explain how I solved that puzzle…