zero pressure, open the test chamber door and
disconnect and remove the test hoses.
After you complete the pneumatic test, stop the
operation of the test stand. Adjust the air pressure
regulator for a zero reading on the regulated air
pressure gauge. Shut off the air supply shutoff valve.
Open the high-pressure air bleed valve. When the
high-pressure air gauge indicates a zero reading, drain
the water by means of the drain valve at the bottom of
the chamber. Open the test chamber doors and
disconnect the test hose.
HOSE AND HOSE ASSEMBLY
Learning Objective: Recognize the mainte-
nance procedures and practices associated
with hose and hose assembly maintenance.
Maintenance of hose and hose assemblies at the
organizational level is limited to contamination
control, preventive maintenance, removal,
installation, or replacement. Proper maintenance
practices can minimize the problems that might occur
with regard to hose and hose assemblies.
Do not use hose or hose assemblies as foot or
hand holds. Do not lay hose or hose assemblies
where they may be stepped on or run over by vehicles.
Do not lay objects on hose or hose assemblies. Turn
the swivel nut when loosening or tightening fittings.
Hold the socket only to prevent the hose assembly
from turning. Perform all necessary turnoff or shut-
down procedures as outlined in the applicable
maintenance instruction manuals (MIMs) or technical
directives before removing any hose or hose
assembly. Cover open ends of hose, hose assemblies,
and fittings with protective closures. Make sure hose,
hose assemblies, and connection points are cleaned
Preventive maintenance consists of periodic
inspection and correction of hose and hose assembly
faults. In this process, you must check for leaks,
wear, and deterioration. Special attention must be
paid to hose or hose assemblies and clamps.
Checking For Leaks
Hose or hose assemblies should be replaced when
leaks are found to be caused by damage to any part of
a hose or hose assembly; poor seating or damaged
threads of the socket or nipple assembly, which causes
the fitting to leak; or excessive torque. If a leak
appears in the swivel nut area, check that the swivel
nut is properly torqued. If necessary, disconnect
fitting and check for contamination or damage. If the
leak persists after cleaning, and the swivel nut is
properly torqued, replace the hose assembly.
Checking For Wear and Deterioration
Check hose and hose assemblies for signs of wear
and deterioration. Replace any hose or hose assembly
when a chafe guard appears worn or shows signs of
cracking; when a firesleeve is worn through, torn, cut,
or oil soaked; when hose or hose assembly has
weather protective coatings or sleevings that are
worn, cracked, or torn, thus exposing the hose or hose
assemblies to corrosion.
Checking Hose or Hose Assembly Installations
Check hose or hose assembly installations
carefully. Proper routing and clamping in accordance
with applicable MIM is mandatory. If retaining wires
on swivel nuts are backed out, replace the hose
assembly. Look for kinks or twists. Observe lay line,
if possible. A kinked hose or hose assembly must be
replaced. A twisted hose or hose assembly may be
relieved by loosening clamps and swivel nuts, and
then straightening the hose by hand. Retorque the
swivel nuts and tighten the clamps. A preformed
hose, or hose assembly, may have a smaller bend
radius. Do not attempt to straighten preformed hose
or hose assemblies. Excessive bends or signs of
chafing may be due to loose, oversize, or worn
clamps. Replace oversized or worn clamps, and
tighten the clamp without squeezing the hose.
You should check the clamps to make sure they
are the correct type and size, that the position of the
hose is correct within the clamp, and that the cushion
material is positioned correctly. Reposition hose and
clamps as needed.
Cushion material should NOT
between end tabs of a closed clamp. Do
use clamps with fuel-resistant cushioning