TM 3-4240-212-14&P
TECHNICAL MANUAL
HEADQUARTERS
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DEPARTMENT OF THE ARMY
No. 3-4240-212-14&P)
WASHINGTON, DC, 1 July 1975
OPERATOR'S ORGANIZATIONAL, DIRECT SUPPORT, AND GENERAL
SUPPORT MAINTENANCE MANUAL
(INCLUDING REPAIR PARTS AND SPECIAL TOOLS LIST)
BREATHING APPARATUS, OXYGEN-GENERATING, M20
(NSN 4240-00-678-5263)
Current as of May 1975
Paragraph
Page
CHAPTER
INTRODUCTION
SECTION
General
Scope ............................................................................................................ 1-1
Record and report forms ................................................................................ 1-2
Description and data
Description..................................................................................................... 1-3
Tabulated data............................................................................................... 1-4
Use and functioning
Use................................................................................................................ 1-5
Functioning .................................................................................................... 1-6
Use of spectacles........................................................................................... 1-7
CHAPTER
OPERATING INSTRUCTIONS
SECTION
Preparation for use ........................................................................................ 2-1
Before operating ............................................................................................ 2-2
Assembly breathing apparatus
Operating Under Normal Conditions
Starting Apparatus ......................................................................................... 2-3
Putting on apparatus ...................................................................................... 2-4
Using apparatus............................................................................................. 2-5
Stopping operation......................................................................................... 2-6
Removing and disposing of canister ............................................................... 2-7
After Operating .............................................................................................. 2-8
Operation Under Unusual Conditions
Using breathing apparatus in cold weather .................................................... 2-9
CHAPTER
OPERATOR'S MAINTENANCE
SECTION
Troubleshooting
Scope ............................................................................................................ 3-1
Maintenance Procedures
Testing pressure relief valve........................................................................... 3-2
Adjusting and testing facepiece group ............................................................ 3-3
Testing timer.................................................................................................. 3-4
CHAPTER
ORGANIZATIONAL MAINTENANCE
SECTION
Service upon receipt of materiel.
Servicing new (or used) equipment................................................................. 4-1
Preventive-maintenance checks and services
General.......................................................................................................... 4-2
Explanation of columns .................................................................................. 4-3
Organizational Troubleshooting
Scope ............................................................................................................ 4-4
Assembly of Facepiece Group
Head harness................................................................................................. 4-5
Lens and lens clamp ...................................................................................... 4-6
Breathing tubes (exhalation and inhalation) .................................................... 4-7
Pressure relief valve....................................................................................... 4-8
Timer knob .................................................................................................... 4-9
Timer and bracket assembly .......................................................................... 4-10
Harness assembly ......................................................................................... 4-11
Breathing tube strap....................................................................................... 4-12
____________
*This manual supersedes TM 3-4240-212-15, 13 September 1960, and TM 3-4240-212-25P, 24 July 1967,
including all changes.
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