Jordan Valve Mark 688 Series - Piloted Soft Seat Regulator - Manual (Page 9)

Diaphragm Replacement
1. Remove all pressure from the line as outlined under
WARNING.
2. Remove the compression on the adjusting spring
(14) by rotating the adjusting screw (19) counter-
clockwise.
3. Remove the spring housing (17). Remove the spring
(14) and spring seat (15).
4. Lift the diaphragm assembly. This diaphragm as-
sembly consists of the upper diaphragm plate (13),
diaphragm (11) and lower diaphragm plate (12).
5. Secure the upper diaphragm plate in a vise. Use a
spanner wrench on the lower diaphragm plate and
turn counter-clockwise to loosen and remove.
6. Remove the diaphragm, clean the parts and install
the new diaphragm in reverse order. Pull the parts
up tight when a metal diaphragm is used. When
elastomer diaphragms are used, clean and degrease
the threads, apply one drop of #290 Loctite to the
threads, and assemble. (Loctite Primer T may be
used to degrease). Thread the parts together, hand
tight, and then tighten 1/8 to 1/4 turn.
7. Clean the diaphragm seating surfaces on the spring
housing (17) and on the body (1).
8. Unscrew the cap (2) approximately two turns to
retract the stem. Place the diaphragm assembly,
spring, spring seat and ball bearing back onto the
valve body. (Metal diaphragms nest into the counter-
bore in the body).
9. Install spring housing. Tighten bolts (18) evenly per
chart.
10. Thread cap back into the body and pull snug.
Seat and Plug Replacement
1. Remove all pressure from the line as outlined in the
WARNING.
2. Turn the hex end on the cap (2) counter-clockwise
and remove it from the body. The plug (3) and return
spring (5) will come out with the cap.
3. Remove the seat (9) with a deep drive socket.
4. Inspect parts for wear and replace as required.
5. Clean all parts in the body and on the cap. Lightly
lubricate these surfaces.
6. Reassemble plug spring into cap and check for
smooth operation.
7. Install seat with a light coat of Teflon paste on the flat
seal area and anti-seize to the threads.
8. Install bottom cap onto the body with a light coat
of Teflon paste on the flat seal area and anti-seize
on the threads until it bottoms out on the body and
tighten.
Warning
Never substitute a longer length adjusting screw. Per-
sonal injury and damage to the valve may result.
Maintenance
WARNING
Be sure that there is no pressure in the valve before
loosening any fittings or joints. The following steps are
recommended:
1. Close the inlet shut-off valve.
2. Allow pressure to bleed off through the downstream
piping. Do not attempt to reverse the flow through
the valve by bleeding pressure from the upstream
side of the valve.
3. When downstream pressure gauge indicates no
pressure in the line, close the outlet shut-off valve.
Refer to the drawing for the proper orientation of the
parts and for proper nomenclature.
Troubleshooting
Erratic Control
•
Oversizing causes cycling and hunting, and reduces
the rangeability of the regulator. Make certain that
your sizing is correct.
• Steam traps downstream may need attention.
• Safety valve may be jammed open, disrupting the
system. Repair as necessary.
• Excessive foreign matter on seat of plug (3)*.
Clean them. Inspect seating surface on plug for
deterioration.
• Valve stroke may not be moving freely. Check stem
(22), bushing (10) or cap bore (2).
Downstream pressure build-up
•
Seats deteriorated. Inspect for foreign material be-
tween plug (3) and seat (9).
• Diaphragm (11) failed. Use metal seats for tighter shut-
off. Consider elastomer seats.
Cannot Maintain Regulated Pressure
•
Clogged strainer or lines.
• Inlet pressure low.
• Spring (14) set too low or broken.
• Valve is undersized for rated flow.
• System demand exceeds pump capacity.
* See back page for parts call-out.
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