1. Visual inspection
When I get in the pump first to see if the packaging is intact or bump without being squeezed and obvious traces of not proceeding due to rough handling during transportation are likely to lead to pump some parts, screws, loosening of the Cup,magnetic springs and other parts of the, which is one of the resonance and very difficult to solve.
2. Vibration, sound
Pump power with no pipe, internal in a load-free State and vent the air flows and other factors will be a lot of noise, regardless of grade level like this, so we can hold the outlet with your fingers this time, temporarily put an end to the sound outlet, carefully listen to the sound vibration, based on the vibrations of a sound to select.
3. Exposure testing
So-called exposure tests, is the air pump itself foot with fix rigid objects such as glass, desktop, repeat the second step after power, observe the contact under the noise is within an acceptable range.