Furnace is not working :-(

[The Codfather]

Originally Posted by wingedfish

Ps scratching a flame sensor won't hurt it. Might cause it to get dirty faster, but it will work fine no matter what you clean it with.

If you scratch the flame rod with sandpaper, you will change the ratio of 1:4, therefore the rectified flame signal will not be correct when it returns to the module and the furnace will lock out because it cannot prove flame. So, scratching the flame rod does make a difference, and I have no idea how scratching it would make it get dirtier faster.
Just my 2 cents.