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- Opening and closing torque is excessive
| A butterfly valve may have jerky operation for the following reasons: |
| The packing is too tight |
Loosen the packing torque until it is only hand tight. Tighten to the required level and then cycle the valve. Re-tighten, if required. CAUTION: Always follow safety instructions when operating on valve. |
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| The shaft seals are dirty or worn out |
Clean or replace components, as per assembly-disassembly procedure. CAUTION: Always follow safety instructions when operating on valve. |
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| The shaft is bent or warped |
| The shaft must be replaced. Remove valve from service and contact GM Engineering. |
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- Operation is not smooth
| A butterfly valve may have jerky operation for the following reasons: |
| The actuator/shaft adaptor is misaligned |
| Remove the actuator mounting and realign. |
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| The packing is too tight |
Loosen the packing torque until it is only hand tight. Tighten to the required level and then cycle the valve. Re-tighten, if required. CAUTION: Always follow safety instructions when operating on valve. |
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| If the valve has a pneumatic actuator, the air supply may be inadequate. |
| Increase the air supply pressure to standard operating level. |
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- Valve shaft won't rotate
| Any combination of the following may prevent the valve shaft from rotating: |
| The actuator is not working |
Replace or repair the actuator as required. Please contact GM Engineering for assistance. |
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| The valve is packed with debris |
Cycle the valve and then flush to remove debris. A full cleaning may be required if flushing the valve does not improve valve shaft rotation. |
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| The shaft key has sheared |
| Contact GM Engineering as a replacement shaft key is required. |
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