Aqua Lung ABS SECOND STAGE Technical Maintenance Manual page 11

ABS Second Stage Technical Maintenance Manual
Second Stage Air Flow Test
1. Connect the first stage regulator to a calibrated test bench
and pressurize the system to 3000 (±100) psi.
2. Place the second stage mouthpiece over the mouthpiece
adapter. Slowly turn the flowmeter control knob until the flow
reaches a minimum of 14 SCFM (400 liters per minute). The
reading on the Magnahelic gauge (inhalation/exhalation effort
gauge) should indicate no more than +6.O" H
reading exceeds +6.0" H
Table 1: Troubleshooting Guide (p. 12) for corrective guide-
lines and specific procedures.
Second Stage Opening Effort Test
1. Turn the flowmeter control knob shut, and then slowly
reopen while watching both the Magnahelic gauge and the
intermediate pressure gauge.
2. When the intermediate pressure gauge begins to drop
below the intermediate pressure "lockup," the Magnahelic
gauge should indicate an opening effort of +1.2" to +1.6".
If the opening effort is not within this range, refer to:
Table 1 - Troubleshooting (p. 12).
Second Stage Purge Flow Test
1. Turn off the flowmeter control knob. Next, while the
second stage is still mounted on the mouthpiece adapter,
watch the flowmeter gauge and depress the purge button
until the second stage valve is completely open. The flow-
meter gauge must indicate a minimum of +12 SCFM. If the
purge flow is less than +12 SCFM, refer to:
Table 1: Troubleshooting (p. 12).
2. When purge flow is correct, remove the second-stage
from the mouthpiece adapter on the flow test bench. Shut
the valve of the test bench, and purge the second stage to
depressurize the system. Remove the regulator.
External Leak Test
1. After disconnecting the regulator from the flow bench,
connect it to a scuba cylinder filled to approximately 3,000
psi. Open the cylinder valve to repressurize the regulator,
and submerge the entire system in a test tank of clean water.
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, assembly 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 disassembling 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 (p. 12).
O. If the
2
O, refer to:
2
Subjective Breathing Test
1. Depress the purge cover fully to ensure that an adequate
volume of air needed to clear the second stage flows through
the mouthpiece. Then, inhale slowly but deeply from the
mouthpiece. A properly serviced and adjusted regulator
should deliver air upon deep inhalation without 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 (p. 12).
This concludes annual service procedures
for the ABS Second Stage.
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