# Older Rheem with Nox rods



## Kirwinjd (Jan 7, 2013)

Did a call today on an older Rheem up-flow furnace with two Nox rods in each of the 4 burners.
The burner hi limit switch had popped. After cleaning the heat exchanger with compressed nitrogen and replacing the dirty air filter, I fired up the furnace. In 3 of the burners the rods looked in pretty good condition. In the fourth, it showed substantial warping. It was that burner that was closest to the burner high limit switch. Anyone have information to pass regarding these furnaces? Thanks


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