Does the device have power?

If the device has power, the blue LED in the center will be illuminated.  If you determine that the device is not powered, check the neutral connection.  

The device has power, but it is not operating correctly.

To test the microprocessor in the GarageVent™, momentarily short the two screw terminals on the sensor tower.  The fan should turn on and run for the set delay time immediately.  

My GarageVent™ only runs for 10 minutes after I turn the breaker on.  

After 10 minutes of doors being opened, the fan will automatically shut off because of a built-in timer.  Naturally, when a door is opened there is plenty of ventilation so there is no need to waste energy running the fan.  However, if the doors are not open and the fan still shuts off after 10 minutes it is very possible that the wiring to the switch is shorted somewhere.  The switches on the GarageVent are Normally Open type. They close when the door opens up. The GarageVent™ thinks the door(s) are open.

Is the device wired according to the wiring diagram?

The device will not operate appropriately if it is not wired according to the below wiring diagram: