Maintenance
!
WARNING
Only qualified service personnel should
attempt to repair these valves. Before
starting any type of repair, close off the
upstream valves and remove all pressure
from both the inlet and outlet of the
Type N550 Emergency Shutoff Valve.
At least once a month, inspect and check the
following things:
1. See that the remote release is properly
connected, works freely, and is not worn.
Operate the release to make certain it closes
the valve. If the valve closes slowly, packing
replacement (refer to form MCK-1155,
D450042T012) may be required.
2. Make sure that the lever, latch, and release are
working smoothly. The latch parts and lever are
easily accessible for replacement or repair by
removing the securing bolts.
3. Check for packing and joint leakage.
Replacing Internal Parts
Type N550 can be repaired in the field. However,
due to the special fire resistant seals and assembly
techniques, repairs should be done only by trained
personnel. If repair should become necessary,
contact your local LP-Gas Equipment Distributor for
information and assistance.
Only parts manufactured by Emerson Process
Management Regulator Technologies Inc., should be
used for the repair of Fisher Type N550 Valves. Be sure
to give the complete type number of the Type N550
when corresponding with your local distributor.
Type N550 valves that have been disassembled for
repair must be tested for proper operation before being
returned to service.
Figure 6.
Type N550 Shutoff Valve Assemblies
9
34
35
63
39
36A
37
38
21
20
19
33
32
61
23
62
22
24
15
18
31
30
29
28
27
26
25
16
NAMEPLATE WITH ARROW INDICATING
FLOW DIRECTION
VIEW A-A
41
43
45
WITH ITEM 46 (NUT)
NOT SHOWN
TYPE N550-10 ONLY
40
41
8
17
42
47
58
3
75 FOOT-POUND
(102 N•m)
1
5
4
7
6
2
A
A
10 TO 15 FOOT-POUNDS
(14 TO 20 N•
m
)
APPLY LUB/SEAL/ADH
INCHES
(mm
)
T40335
7
Type N550
