Quadra Fire 800 combustion blower

I just bought a used Quadra Fire 800 Nova. When I plugged it in the combustion blower started and would not shut off without unplugging the power chord. It acted the same wether or not the thermostat was connected. I understand it is normal for the blower to start and run for 10-20 minutes when the power is first turned on. I let it run for over an hour and it did not shut off.
Any suggestions on trouble shooting would be greatly appreciated.

Is it the control box that controls the start and shutdown of the cumbustion blower or is it controlled by some sensor? The blower runs smooth and quiet. Just won't shut down.