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Masoneilan 77-6 Model Air Lock-up Valve Instruction Manual | 5
Maintenance
Due to their design and intended application,
maintenance difficulties are not expected to be
encountered with these valves. If they fail to perform in
a satisfactory manner, it may be due to accumulation
of dirt in one or more of the parts. If necessary to
disassemble, proceed as follows, after: (1) shutting off
supply pressure; and (2) relieving spring compression by
backing off the adjustment screw.
Remove the four body cap screws (16); body cap (15),
body cap O-ring (14), range spring (3), upper spring
button (2) and spring case (9) will come free from body (7).
To free diaphragm S/A (10) and inlet valve S/A (12) from
the body, place the wrench on the insert retainer (13) and
unscrew from the body insert (5). Remove the body insert
O-ring (6) and slide the diaphragm S/A, the body insert
and the inlet valve S/A from the body. Holding the inlet
valve from turning, unscrew inlet valve locknut (4) and
remove diaphragm S/A from the inlet valve. Turn the inlet
valve out of body insert.
Check all ports to be sure they are clear of dirt. Inspect
the diaphragm S/A for rupture or for damage around the
edge. If necessary, install a new diaphragm S/A. Check
the inlet valve for wear. If the inlet valve is roughed-up or
pitted, replace with new one.
To reassemble the lock-up valve, perform all operations
in reverse order to that used in disassembly. Note: The
O-ring on the inlet valve stem should be lubricated before
the inlet valve is reassembled in the body insert.
Note: Considering the high labor costs involved in
replacing internal parts, it may be more economical
to stock complete units.
Prior to performing maintenance on the Air Lock-up
Valve, shut off the supply pressure and remove the
spring compression by backing off the adjustment
screw.
It is recommended that the Air Lock-up Valve be
removed from the line for repairs.
Ref.
Qty
Part Name
Ref.
Qty
Part Name
1
1
Adjusting Screw
9
1
Spring Case
2
1
Upper Spring Button
10
1
Diaphragm S/A
3
1
Range Spring
11
1
Inlet Valve O-Ring
4
1
Inlet Valve Locknut
12
1
Inlet Valve S/A
5
1
Body Insert
13
1
Insert Retainer
6
2
O-Rings
14
1
Body Cap O-Ring
7
1
Body
15
1
Body Cap
8
1
Locknut
• 16
4
Body Cap Screws
• Not visible in cutaway view.
Signal Pressure
16
