Help with water fitting leak.

[Tater]

Long story short changed out my hot water tank now I can’t seem to get this fitting (the one into the tank) to quit dripping. Used Teflon tape on the first try and a liquid sealant on the second try. May have pulled the threads with the Teflon tape. Going to try a new fitting, anybody have an idea what else I can try? Thanks

[Oz]

Would try a new fitting since you think the threads may be damaged beyond using normal stop leak methods. Also check the angle to see that it's square so that there's not a pull on it causing pressure on the fitting. (I don't think that would be an issue unless it's really badly off square though).

[Rickf1985]

Which one is dripping? The one going into the metal pipe or the other one. If it is the one going into the metal pipe that looks to me like it is in too far which leads me to believe the threads are damaged so go with a new fitting. Plastic fitting and teflon tape should be no more than hand tight.

If it is the other fitting that is a compression fitting and does not use teflon tape or sealant but does need to be straight.

[Tater]

It's the one going into the tank. Thought I read somewhere not to use Teflon on plastic fittings?

[Rickf1985]

I usually do not use any type of tape or sealant unless I have a problem first, then I will resort to the tape. Sometimes the cheaper metal pipe threads are really rough and you need some extra help. You should not in this instance. And do not over tighten.

[Tater]

It’s the lower fitting on the aluminum hot water tank I guess you never know but the threads could be buggered from the factory as the top one is fine and doesn’t leak. Thanks for the help.

[TerryH]

I had a similar problem a couple of years ago. Leak was where the 90 degree elbow fitting connects to the Pex fitting on the line. Tightening, and especially over tightening will make it worse. Sometimes loosening a touch will reseal. Sounds strange but in effect you are actually sealing the threads. Over tightening just damages them more.
In my case I could not source the elbow. I did find a short steel braided line that fit the elbow and has an incorporated ball valve. I used that, with a new connecting fitting to the Pex.
No problem since.
Since that I have added the same braided line with valve to my toilet and galley sink when I was working on them. I will also add them to the shower and vanity sink when I have to work in those areas. Advantage is you can easily isolate a problem area with a simple turn of the valve.
Further, the leak was slow and somewhat isolated. Took me a while to notice it, but caused enough damage to my flooring that I have replaced it. Fortunately no structural damage.
While accessing fittings, etc. I came across a small 9volt water alarm. Bought one and tested it and was very impressed. I now have 4 placed where leaking water is likely to gather. Alarm is loud, like a smoke detector. I change the batteries at the same time as I do the smoke and CO alarms.

[CapnDirk]

Are you sure it's the fitting?  Did you buy a used water heater?  You may have disturbed a cracked weld.  My tank was cracked at the weld,


You can use a Sharkbite fitting (brass) to replace.  They grab to the outside of the Pex, so no need for the special crimp tool.

[Tater]

Yes it's the fitting as it is a brand new tank. Thanks for the info on the shark bite fitting.

[BrianB]

I had the exact same 90 elbow on my hot water tank (86 Chieftain). Flare on the tubing end, pipe thread on the tank side.

Mine broke off trying to get it out. I found an "exact replacement" in brass at my local plumbing supply house (not a big box). Fairly standard fitting, just not in plastic.