Jordan Valve Mark 79/79MX Series – 3 Way Mixing/Diverting Valve - Manual (Page 3)

-3-
Back out the four alien head set screws (22) which 3.
will allow the valve body (12) to be separated from
the valve yoke (21).
Loosen the disc pin nut (7) and rotate the disc pin
4.
(6) counterclockwise, pulling valve stem (17) up-
ward while doing so. DO NOT remove the valve
stem completely but raise it sufficiently so that the
disc pin may be removed by pulling up and out.
Replace the disc pin so that the cast “B” on the disc
5.
pin faces up and is on the normally open side of
the body and reassemble in reverse order following
the procedures outlined under “VALVE SEATS” and
“STROKE ADJUSTMENT”.
Packing
To replace the packing, the valve need not be removed
from the line; however, PRESSURE MUST BE REMOVED
FROM THE VALVE!
Remove connector assembly (18). 1.
Remove both packing flange nuts (16). 2.
Remove packing flange (14) and packing follower 3.
(13).
Should packing spring (9) not eject packing set
4.
(10), a slight amount of upstream pressure might
be necessary to remove the packing set. (Note: on
Mark 79MX version, downstream pressure might
be necessary to remove packing.)
Remove packing retainer (11) and packing spring
5.
(9).
Clean packing bore with solvent and blow out thor-
6.
oughly.
Assemble in reverse order and tighten packing nut
7.
(16) so that packing follower (13) bottoms out on
top of valve body.
Engage valve stem (17) and actuator stem (27) with
8.
connector. Tighten connector nut and bolt. No
stroke adjustment is required.
Valve Stroke Adjustments
If the valve requires a stroke adjustment after mainte-
nance on one of the above points, follow these proce-
dures.
Make sure that the actuator stem (27) is stroked 1.
fully upward by the spring (29) [no pressure on ac-
tuator.]
Loosen the stem connector nut (20) only enough
2.
to allow the stem adaptor to rotate. DO NOT re-
move the stem connector (18). Proper positioning
of the valve stem and actuator stem must be main-
tained during adjustment of seats.
Orifices on the disc and plate must be in perfect
3.
alignment, in the full open position, on the normally
open seats. Adjust the position of the disc on
the plate by moving the stem adaptor in or out
of the actuator stem until the seats are in perfect
alignment, in the fully open position.
After perfect alignment is obtained, tighten the
4.
stem adaptor lock nut and the stem connector bolt.
Recheck the seat alignment to check that nothing
has moved.
To check the normally closed side, apply 20-25 psi
5.
signal to the actuator. If the seats are not in perfect
alignment, refer to “Valve Seats – Reassembly, Step
4.”
Diaphragm Replacement
To replace the diaphragm, the valve need not be re-
moved from the line, however, PRESSURE MUST BE RE-
MOVED FROM THE ACTUATOR.
Remove the control air line from the actuator 1.
Remove the stem connector (18) by removing stem 2.
connector bolt and nut (19, 20).
Remove compression from springs (29) by turning
3.
actuator stem (27) clockwise (when viewed from
top of the valve).
Remove the actuator case bolts and nuts (37, 38)
4.
and lift the upper case (36) off of the lower case
(28).
Screw the actuator screw (30) completely out of
5.
the actuator stem (27). Remove the diaphragm as-
sembly.
Remove the two lock nuts (31) and remove the dia-
6.
phragm plate (32) and the diaphragm (33) from the
actuator screw (30).
Clean all parts with a good quality solvent. Remove
7.
encrusted material with crocus or very fine alu-
minum oxide cloth. Inspect all parts for excessive
wear and/or damage. Replace the worn or dam-
aged parts. USE ONLY JORDAN REPLACEMENT
PARTS. The use of other than genuine JORDAN
parts may impair their ability to serve you.
Reassemble Actuator:
8.
Assemble the seal (35), diaphragm stop (34), a.
diaphragm (33), and diaphragm plate (32) to
actuator screw (30). Assemble and tighten
two lock nuts.
Place the six springs (29) in lower case (28)
b.
so that they nest over the six screw heads
(26).
Thread the actuator stem (27) onto the actua-
c.
tor screw until the springs are slightly com-
pressed. The formed bosses in the diaphragm
plate must also nest in the springs.
Replace the upper case (36).
d.
Replace four of the actuator case bolts and e.
nuts (37, 38) 90° apart and tighten finger-
tight. Replace the remaining bolts and nuts
and tighten evenly alternating across the ac-
tuator case.