Our furnace was off this morning, watching it try to start there was no orange glow from the hot surface ignitor and the LED flashed 7 times, the manual said it is indication a no light situation. (already knew that) I called my Plumber son in law who called his Dad who happened to be in town in his service truck and dropped off a suitable for modification ignitor. The mounting screw didn't line up with the hole, so I used a binder clip to hold it in place.
Anyway, it fired right up and now it's warm as toast in here. Win, win. I'm buying a spare to keep in the furnace room, plus a new flame sensor since I've cleaned it a few times too.