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TM 07661B-14-1
APPENDIX A
A 3-27. HOSES, TUBING, VALVES, FITTINGS, AND COMMON HARDWARE ITEMS.
a.
General. Refer to figures 3-4 and 3-5 when replacing individual parts of tank plumbing, being sure to take proper
precautions that system is depressurized prior to disassembly of piping. See paragraph 3-12.
CAUTION
Cover open ends of all plumbing using suitable closures to prevent system contamination.
b.
Hoses, Tubing, Valves and Fittings. Removal of hoses, tubes, valves, or pipe fittings from tank piping normally
involves opening the plumbing at the nearest union or hose connection. Pay particular attention to location and
orientation of items before removal to assure correct installation. Basic instructions for disassembly of tank piping into
subassemblies is contained in paragraphs 3-13 and 3-14. Instructions for reassembly and testing after installation also
apply.
c.
Common Hardware Items. For maximum protection against corrosion, use only corrosion resistant replacement
hardware. In event of unavailability of parts, standard hardware can be substituted temporarily. Damaged threads or
rounded corners on nuts and heads of bolts is cause for replacement.
A 3.28. GENERAL CLEANING. Both the dry chemical and AFFF systems are normally closed, therefore, interior
contamination will be limited to that created by the firefighting agents used in the systems. Interior cleaning of
components will normally be limited to those times the components are disassembled for overhaul or corrective
maintenance. Exteriors should be kept clean at all times. Normal daily clean-up routine should be sufficient. Any
approved cleaning solvent may be used for cleaning, and compressed air may be used for cleaning inaccessible areas.
NOTE
Care should be exercised during the cleaning routine to preclude inadvertent movement of
valve handles. Although no damage is likely to result from such handle movement, it could
cause a malfunction in operation when the unit is next used.
There are three exceptions to the general statement concerning cleaning of components. The two nozzle discharge
valves may become clogged and require cleaning on occasion. Additionally, wet or damp dry chemical powder, or
inadequate cleaning of the dry chemical hose after use, can cause caking of the powder in the hose, just as residual
solution in AFFF hose may freeze, plugging that hose.
a.
Cleaning Dry Chemical Discharge Nozzle. The discharge nozzles must be partially disassembled for cleaning.
Disassembly and cleaning steps are as follows:
(1)
Remove the two screws (2, figure 3-12) from the tie bar and separate the Dry Chemical nozzle.
(2)
Disconnect the dry chemical hose.
(3)
Remove the male disconnect adapter (1) from the nozzle.
(4)
Turn nozzle tip (5) counterclockwise to remove it from the shutoff valve body (7). The interior
A 3-35
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