Flowserve Nordstrom Dynamic Balance Plug Valve and Double DB Plug Valve - Manual (Page 22)

Flow Control
Nordstrom Valves
22 Dynamic Balance ® Plug Valve and Double DB ® Double Isolation Plug Valve FCD NVENIM2005-01
Problem E: Leakage at the Stem
Cause E1: Line pressure bypassing Stem Packing
Solution E1
Replace Stem Packing.
a CAUTION: Line pressure must be removed from valve
before changing Stem Packing.
1. Make sure there is no internal pressure trapped inside the valve.
Operate the valve one complete quarter-turn cycle, and then
place the valve in the full open position. If the valve is equipped
with a Relief Fitting, loosen the fitting as a final release for pres-
sure and then tighten it.
2. For wrench-operated valves: Remove the Retaining Ring and
Stop Collar. On multiport valves, note the position of the Stop
Collar before removal. This will ensure the replacement position
of the Stop Collar is correct.
3. For gear-operated valves: Remove the Position Indicator and
Gearing. Remove the Gear Segment and Segment Key from
the Stem.
4. For wrench-operated valves: Remove the Gland Bolts and the
Gland with Weatherseal.
5. For gear-operated valves: Remove the Gland Bolts and the Gland
and Gland Retainer if so equiped.
6. Remove the existing Packing and thoroughly clean the Packing
Chamber surfaces.
a CAUTION: Be careful not to remove the Stem Ring.
7. Install the new Stem Packing set in the following sequence:
a. Zinc Foil Washer
b. First Packing Ring
c. Zinc Foil Washer
d. Second Packing Ring
e. Zinc Foil Washer
8. Prepare the Gland for installation.
a. For wrench-operated valves: Examine the Stem Weatherseal
and replace if necessary. Cement in place using a good-qual-
ity rubber-to-metal adhesive.
b. For wrench- and gear-operated valves: Apply sealant to the
inside diameter of the Gland.
9. Install the Gland and Gland Retainer if so equiped.
a. Straightway valves: Apply a thin film of good-quality gasket
compound to the mating surface of the Body or Gland and
install the Gland. On wrench-operated valves the stop lug is
located on the left when facing the front of the valve.
b. Multiport and Transflo valves: Apply a thin film of good-
quality gasket compound to the mating surface of the Body
or Gland. On wrench-operated valves the stop lug is located
approximately 45 degrees clockwise when facing the front of
the valve.
10. Lubricate the Gland Bolts with a good-quality thread lubricant
and install.
11. Tighten the Gland Bolts as described in the Procedure for Tight-
ening Cap Screws and Nuts.
12. Install the Stop Collar (remember to position it so the valve will
turn clockwise to close and counterclockwise to open) and the
Retaining Ring.
13. Inject sealant : Refer to Problem C.
Problem F: Sealant Fitting leakage
Cause F1: Line pressure bypassing Check Valve
Solution F1
Leakage at the Sealant Fitting indicates that there is leakage around
or through the Check Valve (located behind the Sealant Fitting). See
procedures described in Problem G below.
Problem G: Check Valve leakage
Cause G1: Check Valve Ball not seating properly
Solution G1
Clean or replace the Check Valve. Follow the steps listed in Problem
C, Cause C3.