- Pilot was lit
- Thermostat was calling for heat
- Breakers were on
- Main burner wasn't coming on
Sorry about the quality, cell phone in basement, at least I took a picture of it.
The Robertshaw sp715a control box:
- Turns on the pilot gas
- Jumps a spark until it senses a flame
- Turns on the main burner
You can't really see them in the picture, but 2 of the solder joints on the big black relay that controls the main burner were cracked. I had to run to a store to buy a soldering iron (a $6 firestarter), but it was quicker than driving home to solder them. I resoldered and reassembled the furnace. They've got heat and didn't have to buy a $100 module (or wait in a cold house until I could get one either).
UPDATE: A Few Links