Low Pilot Flame
I ran into a weak pilot flame on my NT22A over the weekend. The flame was so weak that the flame did not impinge on the thermocouple and extinguished itself after a few seconds on its own. Based on the various discussions, I pulled the inline orifice fitting and took a look. What I found was a very crusty pair of holes on the flame side of the orifice fitting. The opposite side was clean as a whistle for some reason. Anyway, I soaked the fitting in Acetone, ran it through an ultrasonic cleaner and then hit it again with a nylon bristle toothbrush to remove the stubborn stuff. The two holes cleaned up nicely and resulted in a very strong pilot flame which allows the furnace to operate correctly. I have heat again...now back to the bathroom floor.
I've attached a couple of pics before an after cleaning