Originally Posted by uncle_bob
No, it's not going to get any quieter as time goes on.
These gizmos often have a fan that is driven by the temperature. When "doing nothing" they don't get very hot and the fan does not run. As they get busy, they heat up and the sensor boosts the fan. At full load the fan goes nuts. There are a lot of computer power supplies that work the same way. If yours is super loud, it likely has a defective / broken sensor.
I have he same unit and there is no fan. My suggestion would be to try to insulate the unit by using rubber washers between the unit and the wall you mounted it on. The wall is probably acting as a resonating sound board for any noise it is producing (which should be no noise). Also make sure it is installed correctly and nothing is making contact with the case. A wire against it can cause a vibration.