CONDITION
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POSSIBLE CAUSES
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RECOMMENDATIONS
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- Immediate leakage when system is pressurized
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- Improper tightening of joint
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- Check for O-ring damage and
re-tighten connection to the recommended torque value
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- Undersized tube diameter resulting in tube slippage during flanging
- Die gripping surface is worn or
dirty
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- Verify that the O.D. is correct; if undersized, replace tube
- Inspect die gripping surface; if clogged or excessively worn, clean or replace
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- Sleeve is positioned incorrectly in die
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- Check for proper positioning of sleeve in die; if over-flanged, replace tubing
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- Tubing was not cut properly
- Tube was not properly supported during flanging
- Tubing is eccentric
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- Cut tubing within 90° ±1°
- Support tubing so that tube end is perpendicular to tube stop during flanging
- Replace with quality tubing
- Replace out-of-round flanges
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- Replace tubing using recommended quality tube
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- Improper deburring and cleaning
of tube prior to flanging
- Flange pin not cleaned and
lubricated properly
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- Replace flange using proper deburring and cleaning recommendations
- Keep flanging pin clean and working surfaces well lubricated
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- Poor braze joint/improper joint clearance
- Mixing of sleeve and tube material
- Improper/inadequate flux, braze alloy overrun, or buildup on face
- Improper/inadequate braze temperature
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- Flux and reheat the joint; remove and replace with new sleeve
- Always use steel sleeves with steel tubing and stainless sleeves with stainless tubing
- Apply flux liberally to sleeve and tube end prior to brazing
- Use recommended flux, braze alloy and brazing temperature
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- Misalignment or improper fit
- Damaged, pinched, improper, or missing O-ring
- Extruded O-ring
- Damaged fitting
- Braze overflow on sealing surface
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- Align tube end and connecting fitting properly before tightening tube nut, holding the flat face of the mating fitting against O-ring while tightening
- Replace O-ring, properly installing it in the face seal groove
- Replace O-ring and check for proper alignment and pressure surges exceeding rated pressure of fitting
- Tighten the nut to recommended torque or replace fitting if threads or sealing surface is grossly damaged
- Remove and replace sleeve that has braze overflow on its sealing surface
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