thanks for the tips...flame sensor double checked, reading microamps under
use...i'm afraid ground ( white ) is indeed ground

next step: a ball peen hammer

Don Young wrote:
If the polarity of the incoming power is reversed you will still have
120 volts between black and white and the furnace will do exactly as the
[quoted text clipped - 4 lines]
circuit. Most furnaces will run ok during a/c use that way-- it will not
show up until the heat is fired up. Larry

My furnace installation manual specifically warns about this possibility.
Larry's suggestion and method of testing are both valid.

Don Young

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