Plumbing – How should I prepare this compression fit copper tube for use again

copper-tubingplumbingrefrigeratorwater

(Apologies in advance folks – I'm new to compression fit connections so I suspect this is an obvious question).

I'm preparing to reconnect an old copper tube to my water supply line and refrigerator for the ice maker. Here's what I see at the end that's near my sink:

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The key point that concerns me is that there's no compression nut at all and the compression ring/olive is on there pretty good. I'm not sure how this could have happened but oh well.

My current plan of attack is:

1) Cut off the old compression ring section.

2) Lightly clean the end to ensure there isn't any dirt and debris.

3) Place the compression NUT on first (which seems to come with most water supply valves of appropriate size.

4) Please the compression RING on second.

5) Place the tube in the compression seat of the shutoff valve.

6) Tighten the nut.

Is it really that simple or am I missing something?

I'm confused on a few things:

  • What actually tightens the ring seal to the tubing? Is that done when I'm tightening the nut? Or do I need to apply some sort of glue around the base?

  • Do I need to wrap anything in plumbers tape?

  • How far up the tubing should the ring/olive be? In the old piece, it looks like it was placed about 3/8" to 1/4" up but I'm not sure if that's recommended or not.

Best Answer

Yes, quite simple.

  1. use a Scotchbrite pad to shine up the copper tube so the ferrule ring has a clean, gouge free seating area
  2. slide the nut on
  3. slide the ferrule ring on
  4. push the copper tube into the fitting till it seats (fittings I've used have an internal stop at about 1/4" from ferrule seating area, double-check that the fitting is designed this way)
  5. push the ferrule ring into place against the fitting
  6. thread the nut on by hand (make sure the tube doesn't back out of the fitting and till nut is hand tight)
  7. tighten the nut just till the fitting is leak-free (about 1/2 turn from hand tight)

No plumber's goop, no teflon tape on assembly, the seal is formed by compressing the ferrule ring.

Where most people go wrong is to over-tighten the nut for the ferrule ring. The ferrule ring is trapped between two conical surfaces (nut and fitting) that force the ring to bite into the soft copper which both seals and forms a mechanical connection to keep the tube from backing out. Over-tightening causes the ring to dent the tubing, causing leaks and the inability to disassemble and reassemble the fitting as all the give is taken out of the ferrule ring and it cannot compress any more to seal effectively on the next reassembly.

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