NIBCO Flanged End Outside Screw and Yoke Cast and Ductile Iron Globe and Angle Valves - Manual (Page 5)

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2.2 HANDLING AND INSTALLATION
Each valve should only be handled with apparatus that will safely support the valve
weight. Slings should never be placed around the handwheel, stem, or gland adjustment
parts. First, raise the valve to the vertical position and block it. Reposition the slings and
lift the valve vertically. Remove the expendable end protectors, if present, and install the
valve according to the piping layout.
Each valve should be fully opened and fully closed prior to installation, to ensure full
travel of the sealing disc and operation of the stem.
For installation of valves into pipelines, flange bolting and gaskets are governed by the
applicable code for pipeline specification. While the valve is being installed, it should be
kept in the closed position and care should be taken to prevent foreign material from
entering the valve. For flange bolting data, refer to appendix.
After installation, flushing to clean, and during system testing, the gland nuts should be
tightened uniformly, if necessary, until leakage through packing is stopped. Tighten the
nuts just enough to prevent leakage. Excessive tightening may cause difficult operation
of the valve, damage the stem, and shorten packing life.
CAUTION: Care should be taken during handling, installation, and operation to prevent
personal injury and damage to valve components, especially seating surfaces.
3.0 OPERATION
Globe valves are the valve of choice for throttling use. They can also be used for on-off
service where they should be fully opened or fully closed. Tight throttling is a condition
when the valve is only opened slightly or "cracked". This can cause wire drawing and/or
erosion of the disc and seats. It is better to avoid tight throttling. This can sometimes be
done by using a smaller valve size and opening it up further.
4.0 TROUBLESHOOTING
Prior to doing any work on any NIBCO valve, it will be necessary to shut down the piping
system, remove pressure and drain, and if necessary, allow to cool and/or
decontaminate before proceeding.
4.1 LEAKAGE THROUGH THE BONNET JOINT
1. Remove the handwheel from the stem.
2. Mark the body-to-bonnet flanges with a piece of chalk so they can be matched up later.
3. Remove body-bonnet nuts and bolts.
4. Carefully remove the bonnet assembly. Be careful not to nick or scratch the seating
surfaces.
5. Thoroughly clean the body and bonnet internal surfaces.
6. Check the body and bonnet gasket surfaces for any scratches, gouges or other
irregularities.
7. In the event the surfaces are marred, they must be filed or machined flat again. If the
damage is considerable, the body or bonnet may have to be replaced. A competent