Our controls are special because they not only look at the rise and fall of temperature, but they also compare that against time.
If you fan is still cycling on and off even though you are above your desired setpoint, it may be because the control is calculating that if it stops running the fan, the temperature will drop below your desired setpoint. Unplug the control unit and plug it back in to reboot it.
If your fan is running constantly no matter how hot the temperature may be, you most likely have a bad relay in your control. This is typically caused by a nick or cut in your fan wire. Inspect your wire for any evidence of damage and then see our warranty/return information.