IOM-BQ
3
V. SHUTDOWN
1. On systems with a bypass valve, and where system
pressure is to be maintained as the regulator is shut
down, slowly open the bypass valve while closing the inlet
(upstream) block valve. Fully close the inlet (up stream)
block valve. When on bypass, the system pressure must
be con stant ly ob served and manually regulated. Close
the outlet (down stream) block valve.
CAUTION
2. Relax range spring (11) by turning adjusting screw
(13) CCW until removed from spring cham ber (2).
2. If the regulator and system are both to be shutdown,
slowly close the inlet (upstream)block valve. Close the
outlet (downstream) valve only if regulator re mov al is
required.
VI. MAINTENANCE
3. Draw or embed a match mark between body cast ing
(1) and spring chamber casting (2) along
fl
anged
area.
4. Remove all
fl
ange nuts (8) and
fl
ange bolts (7).
5. Remove spring chamber (2), range spring (11) and
spring button (12).
6. Remove the diaphragm subassembly con sist ing
of the piston cap screw (9), pres sure plate (10),
diaphragm(s) (4), piston (3.1) and piston gasket
(5).
NOTE:
Refer to the quantity of diaphragm(s)
(4) in
cor po rat ed in the bill of ma
te ri als listing.
De pend ing on inlet pres sure level, multiple met al
di a phragms may be “stacked”.
A. General:
1. Maintenance procedures hereinafter are based
upon removal of the regulator unit from the pipe-
line where installed.
2. Owner should refer to owner
ʼ
s procedures for
removal, handling, cleaning and dis pos al of non-
reuseable parts, i.e. gaskets, etc.
3. Refer to Figure 1 for basic construction, Figure 3 for
differential construction and Figure 2 for cryo gen ic
construction. For a blow-up of the com po si tion seat
trim, see Figure 4.
4. When counter clockwise (CCW) or clock wise (CW)
rotations are indicated, they are with respect to:
a. Spring
Chamber - as viewed from above look-
ing down towards the closing cap or its normal
lo ca tion.
b. Body - as viewed looking into the body cavity
with the spring chamber removed.
B. Diaphragm Replacement:
1. Securely install the body (1) in a vise with the spring
chamber (2) directed upwards.
7. To disassemble the diaphragm subassembly,
place piston (3.1) in a vise and rotate piston cap
screw (9) CCW.
NOTE:
Rec om mend using lead
jaws when placing the piston in a vise, so as not
to damage the piston grooves.
8. Separate all parts (3.1, 4, 5, 9 and 10) and clean
piston gasket (5) surface on piston (3.1) if piston is
to be reused.
NOTE:
No piston gasket (5) utilized
for composition diaphragm.
9. Inspect pressure plate (10) to ensure no de for -
ma tion due to over-pressurization. If de formed,
re place.
10. Remove diaphragm gasket (6) for metal di a phragm.
NOTE:
No diaphragm gasket (6) utilized for com po -
si tion diaphragm.
Diaphragm Sub as sem bly
SECTION V
CAUTION
Do not walk away and leave a bypassed reg u la tor un at -
tend ed!
SECTION VI
WARNING
SYSTEM UNDER PRESSURE. Prior to performing any
main te nance, isolate the regulator from the system and
relieve all pressure. Failure to do so could result in per-
sonal injury.
WARNING
SPRING UNDER COMPRESSION. Prior to removing
fl
ange
bolts, relieve spring compression by backing out the ad-
justing screw. Failure to do so may result in
fl
ying parts
that could cause personal injury.
