Hello - I've just installed a new hot water tank, and have two leaks. Each leak is at the dielectric unions. The leaks are very slow. I even took the union apart, cleaned the thread, re-applied the teflon tape and put them back together. I have the same slow drip, on both the hot and the cold side.

I cannot imagine that the unions are bad, but it is possible. Has anyone heard of this before and is there something different I need to do with dielectric unions? Is there something special that needs to be applied?

Thank you

Mike

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Originally Posted by buns1525

Hello - I've just installed a new hot water tank, and have two leaks. Each leak is at the dielectric unions. The leaks are very slow. I even took the union apart, cleaned the thread, re-applied the teflon tape and put them back together. I have the same slow drip, on both the hot and the cold side.

I cannot imagine that the unions are bad, but it is possible. Has anyone heard of this before and is there something different I need to do with dielectric unions? Is there something special that needs to be applied?

Thank you

Mike

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Where are they leaking?

At the nipple on the tank?

Or at the rubber washer where the two halves of the union are joined?

They are leaking at the nipple on the tank. Please let me know if you need any other information.

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Originally Posted by buns1525

They are leaking at the nipple on the tank. Please let me know if you need any other information.

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When you applied the teflon tape, did you wrap it clockwise in the direction the unions spin on?

Wrapping counterclockwise will make the tape spin off as you tighten the unions.

I did do it clockwise. Both times in fact, and both times they leaked. I wrapped it around twice, do you think I should wrap it three or four? I didn't want to make it too bulky.

Thanks for the quick responses.

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Originally Posted by buns1525

I did do it clockwise. Both times in fact, and both times they leaked. I wrapped it around twice, do you think I should wrap it three or four? I didn't want to make it too bulky.

Thanks for the quick responses.

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Yikes!

Only twice?

Try 6 or 7 times around.

All right - I'm off. I'll let you know. Thanks much.

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Originally Posted by buns1525

alright - I'm off. I'll let you know. Thanks much.

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Look at it this way; The manufacturers of pipe dope compounds like Laco, Rector Seal or Mega-Loc for example, direct you to completely fill in the threads with their compound. The same applies for teflon tape.

Also, it must be wrapped tightly.

Well, still crossing my fingers, and I'll be more confident in the morning, but so far so good. Thank you so much for the advise. That is something I can use for all future plumbing projects.

Thank you once again

Thanks "iamgrowler". We just installed our water heater and had the same problem with our dielectric unions leaking no matter how hard we tightened it. We used teflon tape but only wrapped around twice! Once we saw this post, and rewrapped the threads with 6 layers of teflon tape, the leaks stopped! Thanks for this heavily important tip! Why doesn't it just ever come with instructions? Haha :)

I had the same problem. I used the thicker yellow gas PTFE tape, 6 wraps. You know you are getting a good seal as there is a smooth lubricated feel to the resistance to the wrench. Got rid of the problem. The source of the problem is in the rough threads in the tank, very poor quality.