We tested the programming for the sensor today to make sure it would turn on and back off the ventillation fan as wanted.  The pictures below were taken during setup and testing.  It appears the ventillation fan doesn't move air very quickly, or we need to use a smaller container to represent the room.  Dave had to take the lid off of the container & fan fresh air into it to get the sensor to shut off the fan.  Something else to think about!

Sharin & Dave setting up test.

Sensor in container to simulate room.

Ventillation fan.

Complete sensor set up with fan running during test.