Initial Inspection Procedure; External Inspection; Pressure Test - U.S. Divers Impulse Service & Repair Manual

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Initial Inspection Procedure

EXTERNAL INSPECTION

1. Visually inspect the first stage filter to check for any signs that
contaminants, such as moisture, rust, aluminum oxide, or
charcoal may have entered the IP hose and second stage.
NOTE: An orange, rust colored residue on the filter usually
indicates that the regulator has been used with a corroded
steel cylinder. Gray or white discoloration may indicate use
with a corroded aluminum cylinder. Advise the customer of
this, and the possible need to obtain service for their cylin-
der. A green discoloration positively indicates that moisture
has entered the regulator, and internal corrosion is therefore
likely to be found.
2. Slide back the hose protectors to inspect the condition of the
IP hose at its fittings and along its length. Check closely for
any signs of deterioration or damage, including blistering and
abrasion, and corrosion of the fittings.
3. Inspect the condition of the mouthpiece to check for torn bite
tabs, holes, or deterioration.

PRESSURE TEST

1. Prior to performing any disassembly, ensure that the second
stage is connected to a first stage with a stable intermediate
pressure of 140 psi (±5), with no open ports or hoses.
2. Connect the first stage to a cylinder that is filled with 3,000
psi, and open the cylinder valve to pressurize the regulator.
3. Turn the second stage adjustment knob completely out
counter-clockwise. A slight leak of airflow should be present.
4. Slowly turn the adjustment knob clockwise, noting the mea-
sure of turns required to stop the airflow. Airflow should stop
between 1/2 to 3/4 turn.
5. Turn the adjustment knob completely in clockwise, and listen
closely to check for any signs of leakage from the second
stage. If necessary, immerse the second stage in water to
locate the source of any leakage found and refer to Table 1 -
Troubleshooting to determine its possible cause.
CAUTION: If the second stage freeflows uncontrollably,
immediately shut the cylinder valve and proceed directly to
the Disassembly Procedure. Do not attempt to further
inspect the regulator while pressurized.
6. Depress the purge button to determine whether sufficient
airflow is provided to clear the second stage of water. Imme-
diately after releasing the purge button, listen closely to ensure
that the second stage does not continue to flow any air.
7. Turn the cylinder valve shut and depress the second stage
purge button to depressurize the regulator before proceeding
to the following Disassembly Procedure.
© 1997 U.S. Divers Co., Inc.
Impulse Second Stage Service & Repair Manual