Big Maxx Heater SN 0253700

[Rmbell]

The LED light is flashing 3 times, the exhaust fan doesn't kick in an the hose from the fan is clear. Last week I would have to flip the power on an off a couple of time before it would start up an purge the vent before starting.

 

[DocDiesel]

There should be an explanation of the three lights flashing on the cover you removed to expose the innards of the furnace. It will tell you what the flashing lights mean.. At least it should be on one of the covers.
You should also see a schematic on that panel. A good picture of that schematic would be helpful. Doc

 

[Steevo]

Here is the LED codes list: