At work a have a Dayton model # FG9A04010DH110 down furnace. Ran out of propane and now it won't heat. Shows code 7, shut down after 3 tries. Purged the line, it has fuel. Cleaned the carbon off the electric start. Looked for any resets but don't see any. Turned off breaker 3 times for 10 minutes and still the led light shows code 7. is it just coincidence that something else went wrong at the same time? What to look for?