Amron 8225-HP, Instruction Manual

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PRE-DIVE PROCEDURES
PRE-DIVE PNEUMO TEST 7.3
The AMCOMMAND II Pneumo section has gauge protectors to protect the pneumo gauges from
over pressurization. However it is good operating practice to use a procedure which will not
damage the gauges when operating a system without gauge protectors. Using a standard
procedure will permit the operator to use a different system without gauge protectors and operate
the system correctly.
Pneumo gauge with a range of 250 FSW/76 MSW has an equivalent full-scale pressure rating of
111.25 PSI. If you exceed this pressure by a significant amount you will cause a permanent
change in the calibration of the gauge. If you exceed 111 PSI by 100% you will destroy the gauge.
Procedure for checking the pneumo gauges:
1.
Pressurize the LP section of the Amcommand II; reduce the output pressure of the
regulator to a pressure less than 100 PSI.
2.
Open the Diver output valve momentarily to reduce the pressure and check the action of
the regulator. Check to see that the output of the regulator stays at less than 100 PSI.
3.
Open Pneumo valve slowly, while watching the depth gauge, check that the gauge needle
is slowly rising and that air is exhausting through the divers pneumo connection (or diver’s
pneumo hose if connected).
4.
Close valve; check depth gauge to see that it reads zero. The gauge should be /-
10 feet of zero. Zero will be affected by changes in atmospheric pressure and/or changes
in altitude. If zero is off by more than 10 feet and there has not been a significant change in
either atmospheric pressure or altitude, suspect that the gauge has been subjected to
over-pressurization and may have suffered damage. Cross-check the gauge or have the
gauge calibrated before using.
5.
Seal the output of the pneumo section. This can be done by capping off the Pneumo
output, or preferable sealing the end of the pneumo hose. Pressurize the Pneumo to 200
FSW and close the blow-down valve. This reading should hold, with out a decrease in
reading. If the reading decreases you have a leak in the system, correct before
proceeding.
6.
Cross-checking the pneumo gauges. Either connect the pneumo outputs together, or
connect the pneumo hoses together and pressurize the system, both gauges should read
the same. If the gauges differ by more than 2%, have the defective gauge calibrated.
Gauge calibration should be compared at several points over the range of the gauge, with
both increasing and decreasing pressure. As a minimum check the gauges over the range
which the gauge will be used.
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