LowFlow JRH Series High Pressure Regulator - Manual (Page 3)

-3-
Refer to Figure 1. Unscrew the lower diaphragm 10.
plate (4) from the upper diaphragm plate (2). Dis-
card the old diaphragm (3) and reassemble with
new one. Use LowFlow replacement diaphragm
only.
Place diaphragm assembly parts (2), (3), and (4)
back into body cavity (1), making sure the small
counterbore on the bottom of lower diaphragm plate
is properly engaged with the narrow tip of the plug
(7) which protrudes through the seat holder (8).
Replace range spring (5), spring seat (10), center-
11.
ing both on top of the upper diaphragm plate (4).
Replace housing (11) and adjusting screw (14).
Even if pressure builds up beyond set up, a regula-
tor may or may not develop bubble tight shutoff.
Pressurize with air and spray liquid leak detector
12.
around body (1) and spring housing (11) to test for
leakage. Ensure outlet pressure is maintained during
this leak test at mid-range spring level: i.e. 25-100
psig (1,7 - 6,9 barg) range spring, 60 psig (4,3 barg)
test pressure minimum.
C. Diaphragm Replacement
Caution! To prevent damage to body, use soft jaws when
placing the body in a vise. Position so that vise closes
over the flats on lower end of body.
Perform Steps 1 - 5 from Section B, Trim 1.
Replacement.
Perform steps 10 - 13 from Section B, Trim
2.
Replacement.
Figure 1: Diaphragm Subassembly
Troubleshooting
1. Erratic Operation; Chattering
A. Oversize regulator; inadequate rangeability
1. Check actuator flow conditions, re-size regulator
for minimum and maximum flow.
2. Increase flow rate.
3. Decrease regulator pressure drop; decrease inlet
pressure by placing a throttling orifice in inlet piping.
4. Install next step higher range spring. Before
replacing regulator, contact factory
B. Worn plug or seat; inadequate guiding
1. Replace trim (possible body replacement)
C. Weakened/broken return spring.
1. Determine if corrosion is causing plug to not move
freely. Replace return spring.
2. Regulator can’t pass sufficient flow
A. Regulator not closing tightly
1. Inspect plug and seat sub-assembly, replace if
worn.
B. Downstream blockage
1. Check system; isolate (block flow at regulator inlet
- not outlet.
2. Relocate regulator if necessary
C. No pressure relief protection
1. Install safety relief valve, or rupture disc.
D. Restricted diaphragm movement
1. Ensure no moisture in spring chamber at
temperature below free point.