Jordan Valve Mark 79/79MX Series – 3 Way Mixing/Diverting Valve - Manual (Page 2)

leakage or improper control.
Clean all parts of the body and cap with a good 6.
quality solvent. The valve disc and the valve plate
then may be cleaned. Place a piece of 4/0 polish-
ing cloth or jeweler’s cloth on a smooth, flat sur-
face, and polish the lapped surfaces. If the parts
are badly scarred, DO NOT attempt to re-lap them,
but return to the factory for repair or replacement.
USE ONLY JORDAN REPLACEMENT PARTS. The
use of other than genuine Jordan parts may impair
their ability to serve you.
B. REASSEMBLY
On the normally open side, place the disc guide in 1.
the body bore with the index pin on the same side
as the scribe line on the valve body. Apply a small
amount of anti-seize compound to the body bore.
Place the disc in the aperture of the disc guide and
2.
engage the disc pin.
In placing the plate in the body, notice that the
3.
index pin hole in the lapped surface of the plate
engages the index pin of the disc guide.
On Normally Open Side
4. : with no pressure on the
actuator, the disc and plate should have the orifices
in perfect alignment, with the slots at 90° to the
stem. It may be necessary to move the seat set in
the bore to obtain this critical positioning. On Nor-
mally Closed Side: apply 20-25 psi to the actuator
to assure the valve is stroked fully. Follow alignment
instructions for Normally Open Side.
Apply a small amount of anti-seize compound to
5.
the cap bore and set the cap onto the plate, being
careful not to move the position of the plate.
Tighten the cap screws uniformly, being cautious
6.
not to apply too much torque. See table on page 4
for torque recommendations. Repeat disassembly
and reassembly per “A” and “B” above for second
set of seats.
Special Instructions for Mark 79MX:
All instructions for the MX version are the same as above
with the following modifications:
The disc pin protrudes through the plate, with the 1.
disc and disc guide located on top.
Upon start-up, it is important to simultaneously
2.
open both inlets slowly. If only one can be done at
a time, open the normally closed side first.
Disc Pin
Remove the valve disc and plate (3, 4) following the 1.
procedure outlined under “VALVE SEATS” above.
Loosen the stem connector nut and bolt (19, 20)
2.
and remove connector assembly (18).
gradually by slowly opening the inlet shut-off valve.
DO NOT fully open the inlet shut-off valve until you
are sure that the controller and control valve have
control of the system.
To shut off the line fluid, close the inlet shut-off
4.
valve first, then the outlet shut-off valves.
Body and cap bolts should be re-tightened per
5.
torque procedures after valve reaches operating
temperature.
Maintenance
Caution: Be sure that there is no pressure in the valve
before loosening any fittings or joints. The following
steps are recommended:
Close inlet shut-off valve. 1.
Allow pressure to bleed off through downstream 2.
piping. Do not cause a reverse flow through valve
by bleeding pressure from the upstream side of
valve.
Shut off air supply to controller and remove control
3.
air line from the valve.
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.
A. DISASSEMBLY
Shut off pressure to the valve. See caution above. 1.
Remove the valve from the line. 2.
Note the scribed line on the side of valve body and 3.
caps. Secure one of the outlet cap hexes (1) in a
vise. Remove the cap screws (2) from the other cap
and lift the cap straight up.
Next remove the valve plate (3) and place it on the
4.
bench with the lapped surface up. You will notice
that there is a locating pin which aligns the valve
plate with the disc guide (5). The scribe line on the
outside of the valve cap and valve body indicates
that this locating pin should be on this side.
Now remove the valve disc (4) and the disc guide
5.
(5), placing the valve disc on the bench with the
lapped surface up. Fingertip pressure should be
sufficient to remove these parts.
It is imperative that the disc pin is not rotated in
disassembly, cleaning, or reassembly, since this
affects the stroke adjustment of the valve.
Improper handling of the seats will result in
-2-