Re-using Stainless Steel Compression Fittings

[duncan.brown]

In the process of tearing down my HLT to fix an element leak, I had to remove my HERMS coil. It's a stainless-steel coil held in by two compression fittings. To get the coil out, I had to unscrew the compression side of the fitting. The ferrule is pretty tightly bound to the coil's tube so it looks like it's not going to be simple to completely swap out the old compression fittings for new ones.

Is it OK to re-use stainless compression fittings?

I know the copper ones are basically useless after one shot, but I'm hoping that I can just reassemble the fittings and re-use them without fighting the ferrule or needing to cut the tube shorter.

 

[aeviaanah]

Yes you can reuse the compression fittings other than the ferrule that is bound to the tube. They make a plastic ferrule you can use instead of a metal one. Also two o rings will work as well

 

[duncan.brown]

Thanks, the problem is that I might have tightened the fitting enough that getting the ferrule off the tube is going to be hard. This at least gives me hope that I can give it another go:

Compression fittings are popular because they’re easy to assembly and then disassemble. You just loosen the compression nut or screw, and you’re on your way. Likewise, re-assembly is just like the first time (don’t lose those instructions!), albeit with fewer nut turns to get to your optimal position. Pro tip: compression fittings can only handle a few dis-assemblies before the ferrules or fitting body require replacing.

https://www.titanfittings.com/Stainless_Tube_Compression_Guide_a/290.htm

 

[bruce_the_loon]

I would at least give it a go. I've had reasonable success with reusing copper compression ferrules as long as the pipe position or length hasn't changed. For example our solar hot water heater system had 2 1" and 3 3/4" compression joints and when we had to remove the collector panel to redo the roof, everything went back in with the original fittings and ferrules and we had no leaks.

Do check each ferrule for scratches and other damage. That would cause issues if the ferrule is scored, chipped or unevenly formed.

 

[bruce_the_loon]

Pro-tip for getting ferrules off - Gentle diagonal cut with a hacksaw as close as you can get to all the way through without hitting the pipe and then stick a flat screwdriver into the cut and twist to pop it open and off the pipe.

 

[duncan.brown]

@bruce_the_loon thanks, I'll give this a go. I'll do a leak test by pumping water with a bit of food coloring through the HERMS coil before declaring success or failure.

 

[bkboiler]

Also...not saying this is maybe the best way for you...
but last time I needed to reuse a compression fitting, I just cut off the swaged tip off the tube...
Got some oil on the ferrule and had to work it loose...
Then I cut my diptube to length AGAIN (long story)...
And installed it VERY tightly. No leaks.

 

[Shockerengr]

I've used a tool like this to remove the ferrules from 1/2" copper pipe (for regular plumbing) - works well for that.
https://www.menards.com/main/plumbi...03-c-8603.htm?tid=-7751590775728251103&ipos=2
something similar may work.

 

[marc1]

For plumbing shutoff valves they make compression fitting ferrule pullers. It works well for me.
Edit: missed the previous post. What they said

 

[Indian_villager]

If it is a swagelok style compression fitting you should have no issue reinserting the previously swaged tubes into the compression fittings and tightening down the nuts.

 

[TrainSafe]

Did you have success?

 

[duncan.brown]

Did you have success?

Yes! I finally got chance to finish the rebuild of my HLT this weekend (after waiting for the JB weld and the silicone sealant to cure) and did a leak test. Thanks to all for the advice.

No leaks from re-using the same stainless-steel compression fittings. For reference, they are Brennan N2404-08-08-SS Stainless Steel Compression Tube Fitting, Straight Adapter, 1/2" Tube OD x NPT Male.