Oren wrote, on Tue, 23 Dec 2014 14:46:23 -0800:

Easy to get around. I bought a "trade" restricted part from Grainger.
They asked and I told them I was from the "government". They had no
account for the agency. Instead, this was a government cash.

I remember that story, as you've said that before, I forget why, but,
probably in reference to an AC part, when I had to fix my sister's AC
unit.

If it matters, I took all three burners out, but, there was nothing I
could see to do with them once they were out, except snap a photo:
https://c4.staticflickr.com/8/7510/1...f06fc142_c.jpg

That did enable me to confirm that the flame sensor, which is on the
lower burner in the photo below, was mounted squarely in the flame:
https://c4.staticflickr.com/8/7467/1...609d3825_c.jpg

Googling for how the flame sensor works, it seems very few people
actually know, or, if they do, they are all explaining something
different.

How does a flame sensor work and how do you test it:
http://heatingandaircooling.com/2012...-flame-sensor/

How does a furnace flame sensor work:
http://www.ehow.com/how-does_4924695...nsor-work.html

How does the gas furnace flame rod work:
https://www.youtube.com/watch?v=uJU3806j2CE

etc. (I'm still reading up on this...)