Jordan Valve Mark 76 Series – High Cycle, On/Off Valve - Manual (Page 2)

than 0.005, clean the sides of the disc guides with
a fine file.
B. REASSEMBLY
Place the valve plate in the body seat recess. In 1.
replacing, make certain that the index pin hole is
on the same side as the indicator markings on the
valve body. Align the disc pin so that it is centered
in the body bore and protrudes through the center
slot of the valve plate.
Place the valve disc with the stamped arrow point-
2.
ing to the indicator markings on the valve body on
the valve plate, engaging the disc pin into the hole
of the valve disc.
Install the disc guide, engaging the index pin.
3.
In replacing the valve cap, note that the indicator 4.
markings on the valve cap and body must be in
alignment.
Install the cap screws and tighten uniformly, diago-
5.
nally from each other. See back page for torque
requirements.
Stroke Adjustment
Rotate the disc pin on the stem until the disc pin is 1.
located near the upper end of the disc pin slot in
the plate.
If the action of the valve is “air-to-close” (direct act-
2.
ing), the orifices in the valve disc and plate should
be aligned and the valve should be in the full open
position. If the action of the valve is “air-to-open”
(reverse acting), apply an air signal to the actuator.
The disc should stroke down to a fully open posi-
tion and the orifices in the disc and plate should be
in alignment.
CAUTION: the air signal should be applied to the actua-
tor, and the valve fully stroked before placing the disc
and plate in the valve body.
If minor adjustment is required to align the orifices, 3.
remove the disc and plate from the valve body and
proceed with step 4.
Loosen disc locknut and rotate the disc pin in the
4.
desired direction to raise or lower it, and re-tighten
the locknut.
Remove the spring compression from the dia-
5.
phragm plate by inserting a screwdriver between
the upper coils of the spring, compressing it down-
ward.
The stem and disc can then be rotated to center
6.
the disc pin in the disc pin slot in the plate.
Replace the valve seats and the cap as outlined in
7.
“Valve Seats” instructions on previous page.
Valve Seats
The valve seats in all Jordan valves are lapped to
a critical flatness. Maintaining such tolerances is
of paramount importance for your assurance of
excellent control and tight shut-off. Do not use
metallic objects in removing the seats. Care in
handling is imperative.
Note: Reference schematic on back page for posi-
tioning and names of parts.
A. DISASSEMBLY
Close shutoff valve on each side of the control 1.
valve.
Remove the control valve from the line.
2.
Note the indicator markings on the side of the valve 3.
body and cap. Secure the outlet body hex in a vise.
Remove the cap screws and lift the cap straight up.
Before removing, check the valve disc for a
4.
stamped arrow. This arrow points to the indica-
tor markings on the body and cap and the index
pin hole in the valve plate. Since the disc can be
rotated 180° in some sizes without affecting the
stroke adjustment, there may be no arrow on the
valve disc. Remove the valve disc and place it on a
bench with the lapped surface up.
A light tapping on the valve body is normally suf-
5.
ficient to loosen the disc guide and plate. Invert the
valve body while holding the disc guide and plate
in place; then slowly let them drop out of the body
into your hand.
Improper handling of the seats will result in leak-
age or improper control upon installation.
It is imperative that the disc pin is not rotated in dis-
assembly, cleaning, or reassembly, since this affects
the stroke adjustment of the valve.
Clean all parts of the body and cap with solvent. 6.
The valve disc and plate then may be cleaned.
Place a piece of 4/0 polishing paper or jewelers
cloth on a smooth, flat surface and polish the com-
ponents using a figure-eight motion. If the parts are
scarred, do not attempt to re-lap them, but return
to the factory for repair or replacement. If the seats
are not scarred deeply, they can be repaired many
times at nominal cost.
The vertical milled sections of the disc guide serve
7.
as a guide for the disc while stroking. A 0.005
feeler gauge should be used to check the clear-
ance between the sides of the valve disc and the
disc guides. To do so, place the valve disc in the
disc guide with the lapped surface facing upward
and check this clearance. If the clearance is less
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