Airzound refill at gas station
trying to refill my Airzound at a gas station with a free of charge pressure check & air pressure refill station, I don't get over 2 bars (30 psi):
- At first the needle is showing 0 bar.
- Then I push the [+] button (= add compressed air) until the needle arrives at 5 bars (= 70 psi).
- Now, I release the tube that I had put on the Airzound's valve, and I hear a zishhhh (air is releasing somewhere).
- However, the horn works and gives some nice sound.
- Checking / measuring the pressure by stacking again the tube onto the valve, I get something like 2 bar (ca. 30 psi).
So: How could air leak and from where?
P.S.: No matter how long I do nothing but letting the compressor's tube sitting onto the Airzound valve, the needle at the gauge station does not release (= it is constant ~5bar/70psi).
What could I have done wrong?