All components of the CLAMPSEALŪ Throttling valve are shown and named in Figure B. CLAMPSEALŪ Throttling valves have several distinctly different design features from other valves. These servicing instructions should be followed closely.

Routine Maintenance
Routine maintenance consists of a periodic tightening of the gland to prevent packing leakage. Graphite packing manufacturers recommend routine replacement of packing after 3 years of service. No other routine maintenance is required.

Adding a Ring of Packing Under Pressure
Packing will eventually wear to the point where tightening of the gland will not effect a seal. When this happens it is possible to add a packing ring under pressure as follows:

1. Open the valve fully and torque onto backseat. See Table 2 for torque. Over torqueing will not enhance the seal and could cause damage.
2. Wait for leakage to stop while the fluid or gas trapped in the packing relieves itself.
   CAUTION: IF LEAKAGE PERSISTS DO NOT PROCEED!
3. Remove handle to prevent accidental movement off of backseat.
4. Use gland wrench (Figure A.) to slowly screw the gland to full height on the yoke bushing, while checking for blow by.
5. Open new graphite filament wiper packing ring at split for insertion around the stem.
6. Slide ring into bonnet chamber and compress by tightening the gland. Loosen the gland to see if another ring will fit. If so, rotate second ring split one-quarter turn from first ring.
7. Tighten gland applying torques listed in Table 3. Rotate stem several times, in both directions, to seat packing.