Chapter 5. DIRECT SUPPORT MAINTENANCE

TM 3-4240-212-14&P

CHAPTER 5

DIRECT SUPPORT MAINTENANCE

Section I. FACEPIECE GROUP

(2) Slide housing clamp over facepiece opening.

5-1.

Valve Assembly, Facepiece

(3) Install facepiece valve assembly in facepiece

a. Removal

opening. The inlet branch containing pressure relief valve

(1) Disconnect breathing tubes from facepiece

must be at right side of facepiece. Stretch rubber

valve assembly (para 4-7 b ).

facepiece to seat facepiece valve assembly.

(2) Loosen housing clamp (7, fig. B-1). If

(4) Install washer and nut on facepiec valve

necessary, remove clamp. Take care not to distort it.

assembly.

Make sure rubber surrounding hole in

(3) Remove nut (3) and washer (4).

facepiece is held firmly between washer and flange on

(4) Work rubber faceblank (2) from around

valve assembly.

facepiece valve assembly. Separate valve assembly

(5) Tighten housing clamp. Take care not to

from facepiece.

distort clamp or damage facepiece.

(5) Remove housing clamp from facepiece.

(6) Install breathing tubes (para 4-7e).

b. Testing Inhalation Check Valve.

(1) Blow into inlet branch of facepiece valve

5-2. Faceblank

assembly Air should pass freely through inlet branch.

a. Removal.

(2) Try to draw air from inlet branch. Inhalation

(1) Remove facepiece valve assembly (pars 5-1a

check valve should close with an audible click and

prevent air passage.

(2) through (5)).

(3) If inhalation check valve does not operate

(2) Unfasten head-harness straps and remove

properly, install a new facepiece valve assembly.

harness.

c. Testing Exhalation Check Value.

(3) Remove lenses and lens clamps (para 4-6 a ).

(1) Try to draw air from outlet branch of facepiece

b. Installation.

valve assembly. Air should pass freely.

(1) Install lenses and lens clamps in a new

(2) Blow air into outlet branch. The exhalation

faceblank (pars 4-6 b) .

check valve should close and prevent air passage.

(2) Install head harness on faceblank (para 4-5b).

(3) If exhalation check valve does not operate

(3) Install facepiece valve assembly in faceblank

properly, install a new facepiece valve assembly.

(para 5-1d).

d Installation.

(1) Moisten inside of facepiece opening with

water. Do not use oil.

Section II. BACKPLATE ASSEMBLY

(2) Pass screw (18) through lower hole in

5-3.

Waist-Strap Eyes

waiststrap eye and through hole in guard and backplate.

a. Removal.

(3) Install nuts (16) and tighten.

(1) Unhook harness snaphooks from waiststrap

(4) Attach snaphooks on harness straps to

eyes (17, fig. B-2).

waiststrap eyes.

(2) Remove screws (18 and 19) and nuts (16)

that fasten waist-strap eyes to guard and backplate

5-4.

Breathing Bag

assembly (13).

a. Removal.

b. Installation.

(1) Loosen hose clamps (2, fig. B-2) attaching

(1) Pass screw (19) through upper hole in waist-

breathing bag tubes to plunger valve (10) and to

strap eye, through hole in guard and backplate, and

inhalation elbow (6) by lifting latches

through eyelet in tab on breathing bag.

5-1