Subjective Breathing Test - U.S. Divers Impulse Service & Repair Manual

Impulse Second Stage Service & Repair Manual
2. Observe any bubbles arising from the submerged regulator
over a one minute period. The recommended time is necessary
due to slower bubble formation that occurs in smaller leaks.
Bubbles indicate a leak, which requires that the system must
be disassembled at the source to check sealing surfaces, assem-
bly sequence and component positioning in order to correct the
problem(s).
NOTE: Extremely small leaks may be better detected by
applying a soap solution or Snoop™ to the leak area. Bubble
streams will indicate the source of the leak. Before disas-
sembling to correct any leaks, rinse the entire regulator
thoroughly with fresh water and blow out all residual moisture
with filtered, low-pressure (50 psi) air. Disassemble and
remedy the problem, referring to Table 1 - Troubleshooting.

SUBJECTIVE BREATHING TEST

1. While the regulator is connected to a cylinder containing 3,000
psi and pressurized, turn the second stage adjustment knob
completely out counterclockwise to the full positive position,
and verify that a slight leak of airflow is present.
2. Slowly turn the adjustment knob in clockwise to verify that the
airflow stops between 1/2 - 3/4 turn.
3. Turn the adjustment knob completely in clockwise to the full
negative position, and depress the second stage purge to ensure
that an adequate volume of air needed to clear the second stage
flows through the mouthpiece..
Turn the adjustment knob back to 1/2 - 3/4 turn negative, and
4.
breathe from the second stage. A properly serviced and ad-
justed regulator should deliver air upon deep inhalation with-
out excessive inhalation effort, freeflow, or "fluttering" of the
second-stage diaphragm. When exhaling, there should be no
fluttering or sticking of the exhalation valve. If any of these
problems occur, refer to Table 1 - Troubleshooting.
This concludes annual service procedures for the Impulse
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© 1997 U.S. Divers Co., Inc.