MSA PremAire System Manual page 10

6. To install the inhalation disc valve:
a. Press the valve disc on the pin in the coupling
housing.
b. Carefully tuck all
edges of the disc
under the housing
lip.
c. Replace the spider gasket (tab up) and press it on
the pin.
d. Place the neckstrap
retaining ring on the
housing. Line up the
"fingers'' with the
housing.
e. Place the locking ring on the adapter.
f. Insert the adapter assembly through the hole in the
retaining ring. Start to thread the adapter slip nut
into the speaking diaphragm housing.
g. Turn the adapter so
that the bayonets are
horizontal. Hand-
tighten the slip nut
until the two adapter
"wings" lock into the
two large tabs in the
retaining ring. Make
sure that each of the
two large tabs on the
retaining ring is fully
seated in both of the
slots on the adapter "wings."
TAL 502 (L) Rev. 0 - 10064385
ULTRAVUE FACEPIECE REPAIR
h. Using the spanner
wrench, tighten the
adapter slip nut until
the slip nut locks
into the spring finger
on the retaining ring.
Continue to tighten
the slip nut so that
the adapter seals
against the spider
gasket. The slip nut
should be tightened
12 to 27 in-lb.
i. Verify each of the following features:
• The adapter bayonets are locked into a horizontal
orientation and can NOT be rotated;
• The slip nut is threaded completely into the face
piece and locked securely; it can NOT be rotated;
• The metal retaining ring is locked into position
and can NOT be rotated;
• There is no loose play in the assembly of parts.
PRESSURE DEMAND EXHALATION VALVE
1. Temporarily fold the headstraps back over the front of
the facepiece lens.
2. Pull the facepiece chin cup out so that you can see
the inside of the exhalation valve.
3. Use the facepiece
spanner wrench to
loosen the valve retain-
ing nut.
4. Unscrew and remove the retaining nut. Then, grasp
the valve cover and gently pull the valve out from the
underside of the facepiece.
Note: The pressure demand exhalation valve is replaced
as a unit. No replacement parts are available. All compo-
nents of each valve must be maintained as a unit. When
cleaning the valve, do not interchange parts.
5. Installing the pressure demand exhalation valve in the
facepiece:
a. Inspect the facepiece rubber for tears or cracks.
Replace the facepiece if it is damaged. Clean the area
around the facepiece mounting hole if necessary.
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