Jordan Valve Mark 56 Series – Air Loaded Back Pressure Regulator - Manual (Page 3)

-3-
your hand, and place it on the bench with lapped
surface facing up.
5. Clean all parts, including body and cap, with sol-
vent. Place a piece of 4/0 polishing cloth or jewel-
ers cloth on a smooth, flat surface such as a sur-
face plate, and polish the lapped seating surfaces
of the disc, plate and disc guide using a “figure 8”
motion. If the parts are scarred, do not attempt to
relap them, but return them to the factory for repair
or replacement. If the seats are not scarred deeply,
they can be repaired at a nominal cost.
6. The vertical sections of the disc guide (on 1/2”
to 1-1/2” sizes) serve as guides for the disc while
stroking. A 0.005” feeler gauge should be used to
check for clearance between this surface, and the
side of the disc. If the clearance is less, clean the
guide surfaces in the disc guide with a fine file.
Reassemby
Sizes 1/2” to 1-1/2”
1. Place the disc guide in the body bore with the in-
dex pin on the same side as the “<” on the body
2. Place the disc in the aperture of the disc guide with
the arrow pointing to the index pin and engage the
index pin.
3. In placing the plate in the body, notice that the
index pin hole in the lapped surface of the plate
engages the index pin of the disc guide.
4. Align the “>” on the cap with the “<” on the body
and place the cap over the two studs in the body.
5. Install the nuts to the two studs and proceed to
Stroke Adjustment to check the orifice alignment of
the seats. Next, torque the body bolts as outlined
under Torque Procedure.
2” Size
1. Place the disc on the plate and replace the guide
screws. Tighten the screws but do not allow them
to bind the disc against the plate.
2. Install the pressure ring and disc and plate assem-
bly in the body so that the disc pin engages the
disc, and the plate is seated firmly in the body.
3. Place a straight edge across the body bolt holes on
the horizontal center line of the valve (perpendicu-
lar to the valve movement). Gently rotate the disc
and plate assembly until the edges of the orifice
slots are parallel to the straight edge.
4. Remove the straight edge and reinstall the cap,
being careful not to rotate the disc and plate as-
sembly.
5. Proceed to Stroke Adjustment to check the orifice
alignment of the seats and then torque the body
bolts as outlined under Torque Procedure on the
back page.
2-1/2” through 6” Sizes
1. Place the plate in the body so the disc pin pro-
trudes through the center slot in the plate. The
marking “TOP DIRECT” on the back of the plate
must be toward the diaphragm. Use new seat gas-
kets.
2. Place the disc on the disc guides in the plate, en-
gaging the disc pin arm protruding through the
center of the plate. The arrow on the disc must
point away from the diaphragm.
3. Install the cap to the body using only two body
bolts 180° apart. Be sure the disc spring is installed
in the center web of the cap and install the cap
with the center web parallel to the stem. Use a new
seat gasket.
4. With no air pressure applied to the upper dia-
phragm case, apply 20 psi minimum air pressure to
the 3/8 NPT sensing line hole under the diaphragm
and check the orifice alignment of the disc and
plate. The orifices should be fully open and in per-
fect alignment. If they are not, proceed to Stroke
Adjustment before torqueing the body bolts per
Torque Procedure on the back page.
Diaphragm Replacement
Disassemby
1. In removing the diaphragm, first remove the disc
and plate as previously covered under Valve Seats.
2. Remove the upper diaphragm case.
3. Hold the disc pin with an open end wrench and
remove the diaphragm assembly by rotating coun-
terclockwise. The diaphragm assembly consists of
the upper diaphragm plate, diaphragm, and lower
diaphragm plate.
4. If the diaphragm must be replaced:
• 1/4” - 2” sizes — secure the upper diaphragm
plate in the vise. A face spanner wrench should
be used to remove the lower diaphragm plate
from the assembly. If a face spanner wrench
is not available, use a punch and hammer, but
make certain to remove all burrs prior to reas-
sembly.
• 2-1/2” - 6” sizes — secure the lower diaphragm
plate in the vise. Use a wrench on the hex of
the upper diaphragm plate and turn counter-
clockwise to remove. If the packing needs to
be replaced, follow these procedures:
a) Remove packing bolts, packing flange, and
packing follower.
b) Remove the packing. The packing may have
a tendency to stick in the packing cavity if
the valve has been in service for some time.
Movement of the stem may help.
c) The packing retainer and spring may be re-
moved if needed.
d) Be certain that all packing material has been
removed. Check the stem for scratches and
replace if necessary. If the stem must be re-
placed, remove the seats as shown in Valve
Seats.
e) Replace the packing. Refer to the drawing
for proper orientation of the packing.
f) Insert the packing follower, place the pack-