Please tell us more, spudder....
What model furnace? (so I can look for a manual)
Has it fired up successfully recently?
If so, can you think of anything that has changed since then? (example- propane refill, batteries went low, etc)
Has the furnace been troublesome in the past?
Can you light your stove? If so, does it seem to be working like you'd expect it to?
Did you happen to have oil come out of your propane line when you've unscrewed it from the tank? (to refill or whatever)
Do you believe you have 11.5 volts or more at the furnace?
When you say 'cycled through it's phases', I assume that means the fan ran for bit and then you heard the distinctive click of the attempt to light. But it never fired. Is that correct? Or did it fire and run for a few seconds and shut down?
Did the furnace attempt to light three times, then run the fan for a while, then shut down?
Have you checked wiring connections on the furnace to be sure there are no obvious problems with them? (like the high-tension wire falling off)
Is the control board stable in its carrier and the carrier securely in place?
Have the control board contacts been cleaned (fairly) recently?
Also- my 8516-IV model has this sticker on the motor cover...
(Click to enlarge)
The flashes refer to an LED on the control board (assuming it's the original board). From your description, I'm guessing you'd be seeing the three-flashes one, i.e., the lockout. Yes?
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