C. Wet Breathing:
1.Improper clearing, or diver diving in total
2.Diaphragm improperly installed.
3.Hole in the mouthpiece at tie area.
4.Hole in the diaphragm.
5.Damaged exhaust valve, or edges of the exhaust valve not firmly seated on the case.
6.Crack in case.
D. Humming or Buzzing During Inhalation:
1.Harmonic resonance between the springs and the mass of the piston.
Instruct the diver on proper clearing technique.
Visually check position of diaphragm.
Replace the mouthpiece.
Replace the diaphragm.
Replace exhaust valve.
Replace case.
Disassemble the first stage and flip the main spring over. Change the position of the piston in its bore. If resonance is still present, install a new piston and spring.
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