Flowserve Valtek Mark One Three-way Control Valve - Manual (Page 2)

3-2 Flowserve Corporation, Valtek Control Products, Tel. USA 801 489 8611
2. Install new seat ring gasket, lower seat ring and
retainer.
3. Insert the plug into the body.
CAUTION: Most three-way seat rings are non-
directional; however, on soft seat and special
seat rings make sure the proper seating surface
is facing the plug.
4. Install the upper seat ring and new gaskets.
5. Lower the three-way adapter over the plug stem
into the body. Make sure the three-way adapter is
aligned with the correct flow direction.
6. Replace the bonnet gasket.
7. Slide the bonnet over the plug stem, making sure
not to gall the plug stem.
CAUTION: Adapters more than two inches have
different gasket recess depths, and must be
installed with the correct bonnet gasket recess
in contact with the correct bonnet gasket re-
cess. Measure the depth of the upper gasket
recess in the body. The bonnet gasket recess in
the adapter is the same depth.
8. Lower bonnet flange over plug stem onto the bonnet.
9. Insert guides and packing into the bonnet, follow-
ing the procedure outlined in Installation, Opera-
tion, Maintenance Instructions 1 (Mark One and
Two Control Valves).
10. Hand tighten the bonnet flange bolting.
11. Apply air to the cylinder so the actuator stem is at
mid-stroke.
12. Lower the actuator and gland flange into place.
Screw the plug stem into the actuator stem by
rotating the actuator in a clockwise direction.
13. Tighten the stem clamp.
14. Replace the yoke clamps.
15. Tighten the gland flange nuts slightly more than
finger tight.
CAUTION: Do not over tighten packing. This
can cause excessive packing wear and high
stem friction.
16. Stroke plug two or three times to center seat rings.
17. Seat the plug in the lower seat ring with air pressure
in the actuator. Tighten two opposing body bolting
nuts
1 /
6
- turn. In this manner, tighten remaining
bolting 1 /
6
-turn.
18. Continue to alternately seat the plug in the lower
and upper seat rings and to tighten the bolting
1 /
6
- turn. Firmly tighten all bolting evenly and com-
pletely, using full wrench force to compress the
gaskets and to seat the assembly metal-to-metal.
Proper tightness requires considerable force. How-
ever, the bottoming of the parts metal-to-metal can
be easily felt through the wrench.
19. When reinstalling the valve in the line, make sure
the flow is in the proper direction.
4. Check for proper, full-stroke operation as indicated
in the “Quick-check” section of Installation, Opera-
tion, Maintenance Instructions 1 (Mark One and
Two Control Valves).
5. If the valve does not function properly, check the
bonnet flange and three-way adapter for
squareness to the body. Gaps between the bonnet
flange and three-way adapter must be uniform for
proper operation. If the assembly is out of align-
ment, loosen the body bolting and tighten according
to steps 16-18 in the “Reassembly” section.
6. If problems still exist, disassemble the valve ac-
cording to the “Disassembly” section.
Disassembling Three-way Valves
To disassemble three-way valves, refer to Figure 1 and
proceed as follows:
WARNING: Depressurize line to atmospheric pres-
sure and drain all fluids before working on valve.
Failure to do so can cause serious injury.
1. Apply air to the cylinder so that plug is at mid-stroke.
2. Loosen the stem clamp and gland flange. Remove
yoke clamps (or yoke bolts, if used). Disengage the
plug stem from the actuator stem by rotating the
actuator in a counterclockwise direction.
CAUTION: Do not allow the plug to rotate. Flats
are provided on the plug stem so it can be held
with a wrench. Prevent the plug from dropping
into the seat ring when the actuator is removed.
Heavy actuators may require a hoist. If a lifting
ring is not provided, use lifting straps around
the yoke legs. Be aware that the center of
gravity may be above the lifting straps.
3. Remove the bonnet flange nuts and bonnet flange.
Carefully slide the bonnet up off the plug stem to
avoid galling.
4. Remove the three-way adapter by lifting it over the
plug stem.
CAUTION: Large adapters may require a hoist.
Lift the three-way adapter straight away from
the body to prevent damaging the plug stem.
5. Remove the upper seat ring and gaskets.
6. Remove the plug. Check the guiding and seating
surfaces for galling and scoring.
7. Remove the retainer, lower seat ring and seat
gasket. Check both seat rings for galling and
scoring.
Reassembling Three-way Valves
To reassemble three-way valves, refer to Figure 1 and
proceed as follows:
1. Clean all gasket surfaces.
NOTE: Use new gaskets whenever the valve is
disassembled.