This typically occures when the EdenPURE 1000XL heater setting is on auto mode and the room temperature has reached the desired temperature.
Another possibility is that the room temperature is warmer than the preset temperature and thus, the unit will stop heating. The fan motor and the bulbs will shut down.
Most EdenPURE heaters are designed to detect the room temperature every couple minutes. The fan is programmed to run for less than 30 seconds every few minutes in order to draw air from the room over the thermostat sensor. This results in more accurate temperature readings.