Flowserve Nordstrom Dynamic Balance Plug Valve and Double DB Plug Valve - Manual (Page 20)

Flow Control
Nordstrom Valves
20 Dynamic Balance ® Plug Valve and Double DB ® Double Isolation Plug Valve FCD NVENIM2005-01
driver. If a small amount of fresh sealant is released through the
Sealant Fitting center button, the fitting is accepting sealant and
operating properly.
If the center button of the Sealant Fitting cannot be depressed,
the Sealant Fitting is faulty or clogged with debris and/or
hardened sealant, and should be cleaned or replaced. Proceed
to Step 2.
If a steady stream of sealant or line fluid is ejected from the Seal-
ant Fitting, the Check Valve is not operating properly and should
be flushed or replaced. See Cause C3 below.
a CAUTION: Before replacing a faulty Sealant Fitting,
remove the valve from line pressure.
2. Test for trapped pressure below the Sealant Fitting by carefully
unscrewing it while attempting to move the Sealant Fitting back
and forth. If pressure is present, continue to move the Sealant
Fitting back and forth until the pressure is relieved.
a CAUTION: Do not remove the Sealant Fitting until all
pressure is relieved.
3. Once the Sealant Fitting is removed, attach the sealant injection
equipment to the Sealant Fitting and inject sealant. If sealant
does not flow from the Sealant Fitting, the Sealant Fitting is
faulty and must be replaced. If sealant can be pumped through
the Sealant Fitting, the problem may be with the Check Valve or
valve sealant-grooving system.
4. Replace the Sealant Fitting, if necessary.
Cause C3: Check Valve blockage
Solution C3
Check Valve blockage may be the result of debris or hardened seal-
ant not allowing the Check Valve ball to move off of its seat.
1. Inject sealant and/or VXX Valve Purge before continuing with
this procedure.
2. Remove the Sealant Fitting as described above in Cause C2
above, Step 2.
a CAUTION: Before replacing a faulty Check Valve, the
valve must be removed from line pressure.
3. Flush or replace the Check Valve if Solution C1 and C2 above are
unsuccessful
4. Using a .188" square tool or a 1/4" Hex wrench, remove the Check
Valve.
5. Once the Check Valve has been removed, clean the removal area
of all debris and check for thread damage. Failure to do so may
allow contaminants to enter the valve sealant system and dam-
age the sealing surface of the Plug and/or Body.
6. Clean or replace the check valve.
7. When replacing the check valve lubricate the threads of the new
check valve with light machine oil and install.
8. Reinstall the Sealant Fitting.
9. Inject sealant into the valve.
Cause C4: Plug seized in the Body Taper
Solution C4
Adjust the Plug.
1. If the Plug cannot be unseated by sealant injection, remove the
Plug Adjusting Screw cover.
2. Loosen the Plug Adjusting Screw by turning it counterclockwise
1 ⁄
8
turn.
3. Inject sealant into the valve and move the Plug Adjusting Screw
back and forth, until the Plug lifts off of the Body Taper.
4. Once the Plug has lifted off of the Body Taper, retighten the Plug
Adjusting Screw until the valve becomes difficult to operate.
5. Loosen the Plug Adjusting Screw 1 ⁄
8
turn.
6. Inject sealant into the valve.
Problem D: Cover leakage
Cause D1: Damaged Diaphragm and/or Gasket
Solution D1
Replace Diaphragm and Gasket. It is recommended that the old
Gasket and Diaphragms be replaced with new parts whenever the
Cover is removed from the valve.
a CAUTION: The valve must be removed from line pressure
before removing the Cover.
1. Be sure there is no pressure trapped in internal cavities of the
valve (refer to the Introduction to the Valve Selection section at
the beginning of this manual). Operate the valve one complete
quarter-turn cycle and then put the valve in the full open posi-
tion. If your valve is equipped with a Relief Fitting, loosen the
fitting as a final release for pressure and then tighten it.
2. Remove the hex-head cap screw, or thin 3-screw bolted plate,
located in the center of the bottom Cover of the valve. This
exposes the Plug Adjusting Screw, the threads of which have
been treated with a thread-locking compound at the Flowserve
Sulphur Springs factory.
3. Loosen the Plug Adjusting Screw until there is no mechanical
load on it.