Leak - Connection Unscrewing Itself ???

[jepalan]

I am DIY homeowner with a good amount of DIY plumbing experience. Installed a Fleck Cabinet unit 2 weeks ago. All joints sealed tight except one started seeping after a week. Retightened and it started seeping again this morning. 4 wraps nickel tape plus pipe dope. Tighten, wait 20 mins tighten again each time. See pic. It is stainless nipple into stainless street elbow. Our house was built in 70’s. Everything is old. No bladder on water heater. No check valve at entry. 80-85psi at entry. I believe as water is used and system pressures up/down, the flex connection is unscrewing the nipple. I marked it with a black line this time to see if I am right. Am I crazy? Is this a thing? If so, suggestions to remedy?

 

[John Gayewski]

Try replacing it with a brass nipple. Stainless on stainless has no malleability.

Either that or that connection needs to be fastened better/ rethought.

 

[Sponsor]

 

[jepalan]

Thanks John. I'll watch it for another week and see what happens first. If it seeps may try cleaning and redressing the fitting and new "blu" pipe sealant before trying brass. Was also hoping for some pro comments re the flex connection unscrewing the nipple - its does move a tiny bit (taps the wall) when water is turned on/off.

 

[jepalan]

So, just following up on this. I loosened the flex connection at both ends and got almost another 1/4 turn on the nipple. Carefully re tightened the flex, making sure to hold the corrugated part while tightening to make sure there was no torque on the nipple from the flex. Everything is bone dry now.