CONDITION

POSSIBLE CAUSES

RECOMENDATIONS

• Immediate leakage when system is pressurized

• Improper tightening of joint

• Check for O-ring damage and
  re-tighten connection to the
  recommended torque value

• Under-flanged assembly

• Undersized tube diameter resulting in tube slippage during flanging
• Die gripping surface is worn or
  dirty

• Undersized tube diameter resulting in tube slippage during flanging
• Die gripping surface is worn or
  dirty

• Over-flanged assembly

• Sleeve is positioned incorrectly in die

• Check for proper positioning of sleeve in die; if over-flanged, replace tubing

• Flange out-of-round

• Tubing was not cut properly
• Tube was not properly supported during flanging
• Tubing is eccentric

• 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 flangess

• Cracked flange

• Tubing too hard

• Replace tubing using recommended quality tube

• Scored, pitted flange

• Improper deburring and cleaning
  of tube prior to flanging
• Flange pin not cleaned and
  lubricated properly

• Replace flange using proper deburring and cleaning recommendations
• Keep flanging pin clean and working surfaces well lubricated.

• Leakage at braze joint

• 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

• 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.

• Leakage at face-seal end

• Misalignment or improper fit
• Damaged, pinched, improper, or missing O-ring
• Extruded O-ring
• Damaged fitting
• Braze overflow on sealing surface

• 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 whichhas braze overflow on its sealing surface.