How to Install and Maintain a Butterfly Valve
1. Critical Rule Before Installation
Always install with disc partially open (10–20°). Never install with disc fully closed – it will damage the seat and pipe flanges.
2. Installation – Wafer Type (Most Common)
| Step | Action |
|---|---|
| 1 | Disc at 10–20° open |
| 2 | Place valve between flanges with gaskets both sides |
| 3 | Insert long bolts through both flanges |
| 4 | Hand-tighten, then close disc fully |
| 5 | Tighten bolts in star pattern (50% → 75% → 100% torque) |
Common mistakes:
-
Over-tightening → crushes body, binds disc
-
Under-tightening → flange leakage
-
Missing gaskets → metal-to-metal leak
3. Installation – Lug Type
| Step | Action |
|---|---|
| 1 | Disc at 10–20° open |
| 2 | Place valve between flanges with gaskets |
| 3 | Bolt upstream flange to upstream lugs (short bolts) |
| 4 | Bolt downstream flange to downstream lugs |
| 5 | Tighten both sides in star pattern |
Lug advantage: Allows dead-end service and downstream pipe removal without system drain.
4. Post-Installation Testing
| Test | Acceptance |
|---|---|
| Visual check | No external leakage |
| Manual operation | Smooth 0° to 90° rotation |
| Seat leakage (closed, pressurized) | Zero bubbles (bubble-tight) |
5. Maintenance Schedule
| Frequency | Task |
|---|---|
| Monthly | Cycle valve (if normally static) to prevent seat sticking |
| Quarterly | Check bolt torque, lubricate stem |
| Annually | Inspect seat and disc for wear/damage |
| As needed | Replace seat (in-line for wafer/lug – 30-60 min) |
6. Seat Replacement – Concentric Valve (In-Line)
| Step | Action |
|---|---|
| 1 | Depressurize and drain line |
| 2 | Remove actuator/lever |
| 3 | Remove stem and disc |
| 4 | Pull out old seat, clean groove |
| 5 | Install new seat, reassemble |
No need to remove valve from pipeline.
7. Common Problems & Solutions
| Problem | Cause | Solution |
|---|---|---|
| Leakage (closed) | Worn seat | Replace seat |
| Leakage at stem | Worn O-ring | Tighten gland or replace seal |
| High torque | Over-tightened bolts | Re-torque |
| High torque | Seat swelling (chemical attack) | Replace with compatible material |
| Sticking after sitting | Seat bonded to disc | Cycle manually (carefully) |
| Flange leakage | Loose bolts or bad gasket | Re-torque or replace gasket |
8. Storage Guidelines
| Rule | Reason |
|---|---|
| Store with disc slightly open (5–10%) | Prevents seat from taking permanent set |
| Dry, indoor location | Prevents corrosion and UV/ozone damage |
| Do not stack heavy items | Protects body and disc |
Never store with disc fully closed.
9. Safety Reminders
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Depressurize and drain before maintenance
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Allow hot media to cool
-
Use LOTO (lock-out/tag-out)
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Use lifting aids for valves ≥12"
10. KINKO Maintenance Support
| Available | Description |
|---|---|
| Spare seat kits | EPDM, NBR, Viton for KBF-LT series |
| Stem seal kits | O-rings, packing, gland hardware |
| Full rebuild | Return to KINKO for factory service |
11. Conclusion
Proper installation (disc partially open + correct torque) and regular maintenance (monthly cycling, annual inspection) will maximize butterfly valve life. Most failures are preventable.
Contact KINKO for spare parts kits or technical support.
Ivan (Mobile:+86-18968769287)
WhatsApp：+86-13579991606
Wechat:+86-18968769287
Website：www.kinko-flow.com
ZHEJIANG KINKO FLUID EQUIPMENT CO.,LTD
