LowFlow Mark 708HP Series 8000 psi Control Valve - Manual (Page 2)

Remove all of the packing and discard. Clean valve 2.
stem and packing box thoroughly. The valve stem
may be dressed with a very fine crocus cloth, but
generally it is best not to as the stem has a fine
machined finish. Use approved non-residue-form-
ing solvent for cleaning. Wipe dry with clean cloth.
Insert a new set of packing in packing box. Press 3.
each ring down in place with a tube as it is in-
stalled.
After packing is installed, assemble packing adapt- 4.
er, gland, and gland nuts. Tighten the nuts hand
tight.
The final packing adjustment should be made with 5.
the valve pressurized and the packing tightened
just enough to stop any leakage, while stroking the
valve. Excessive tightening could cause the stem
to stick and result in improper valve operation due
to high friction forces.
Removing Actuator from Valve
Direct Acting Actuator (ATC) 1. : Shut off pressure
to the actuator and remove supply tubing from
the actuator case. Reverse Acting Actuator (ATO):
Apply approximately 12 psig air pressure to the
actuator to lift the plug off of the seat.
Remove the actuator from the valve as follows: 2.
loosen the two stem nuts and move them down
the stem. Lock these nuts together. Remove the
packing nut and yoke lock nut. Using a wrench on
the nuts and on the flats of the actuator stem, turn
the valve stem (while holding the actuator stem in
place) until the stems disengage. The actuator will
be free of the valve.
Body & Bonnet Disassembly
For actuator removal, refer to section on “Remov- 1.
ing Actuator”.
Remove the bonnet ring nut (4). 2.
Remove stem nuts (32) and indicator (19). Pull 3.
the bonnet (3) straight up and out of the body (1).
Withdraw the plug/stem(5) downward to remove
from the bonnet (3).
Using a hook tool, carefully remove the flex seal 4.
(34) from the groove in the bonnet bore and dis-
card. Using a deep socket wrench, remove the
seat (2) from the body (1).
Clean all parts with a non-residue forming solvent. 5.
Remove encrusted material with a very fine crocus
or aluminum oxide cloth. DO NOT attempt to pol-
ish the seating surface or trim surface (the portion
of the plug that enters the seat bore.) The machin-
ing tolerances on these parts are closely con-
trolled and flow values could change as a result.
Inspect all parts and replace those that are worn 6.
or damaged. The flex seal (34) cannot be re-used
and must be replaced every time the bonnet is
removed, and replacement of the packing set (33)
is generally advisable.
The control valve has been pre-set by Jordan 2.
Valve, however, finer adjustment may be required
to compensate for the system conditions of your
application.
With inlet, outlet and bypass shutoff valves closed, 3.
and no pressure in the down stream line, fully
open the outlet valve. Slowly open the inlet valve
just enough to start flow through the control valve.
Increase the flow gradually by slowly opening the
inlet shutoff valve. Do not fully open the inlet valve
until you are sure that the controller and control
valve have control of the system. Usually, the
handwheel on the inlet valve will turn freely when
this point is reached.
To shut off the line fluid, close the inlet shutoff 4.
valve first, and then close the outlet shutoff valve.
Maintenance
Caution: Make certain that there in no pressure in the
valve before loosening any fittings or joints. The fol-
lowing steps are recommended:
Close the inlet shutoff valve. 1.
Allow pressure to bleed off through the down- 2.
stream piping. Do not attempt to reverse the flow
through the valve by bleeding pressure from the
upstream side of the valve.
When the pressure gauges indicate that all pres- 3.
sure has been removed from the system, close the
outlet shutoff valve, and the valve may be serviced.
Note: refer to the drawing at the end of this docu-
ment for description and proper orientation of parts.
To reduce maintenance time, refer to proper figure and
follow steps indicated below for applicable maintenance
operation.
Proposed Maintenance Procedure Follow Steps...
Renewing stem packing Packing Replacement
Valve Disassembly, Inspecting
Parts, Replacing Plug or Seat Ring
Valve Disassembly
Valve Reassembly Valve Reassembly
Actuator Spring Preload
Adjustment
Actuator Spring Load
Adjustment
Actuator Maintenance Actuator Maintenance
Changing Valve Action Reversing Action
Motor Valve Seat Spring Preload Motor Valve Seat Spring Preload
Packing Replacement
Renew valve plug stem packing if control valve has been
in service beyond normal maintenance, and packing
shows signs of wear. Wear will be indicated by leakage,
which cannot be corrected by minor tightening of the
packing flange. An additional packing ring can be in-
stalled to overcome minor leakage without dismantling
the control valve or breaking valve plug connection.
Remove the actuator from the bonnet. (See Re- 1.
moving Actuator from Valve.)
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