leaking union

[Jim Allen]

Had to do some plumbing repair. Added a 3/4" galvanized union and it appears to be leaking. Any ideas why it would leak?

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[Peter Kelly]

The vibration from your jet pump is causing the leak in the union. Replace it with a Shark Bite slip fitting and it should stop.

[Jim Allen]

Thanks Peter, that's an interesting fitting never heard of it.

[Doug Dawson]

The vibration from your jet pump is causing the leak in the union. Replace it with a Shark Bite slip fitting and it should stop.

Shark Bite is good now? I wouldn’t be so sure about that.

[Aaron Rosenthal]

My guys say that Shark Bite fittings are approved for underground around here.
Still, did you put pipe Teflon on the union? If it's black threaded pipe, I use the paste.

[Peter Kelly]

Looks like you could actually even use a Sharkbite straight coupling fitting if you can move that short length of PEX. Any threaded fittings going into or nearby a jet pump should have both pipe dope and tape. The vibration from the pump will cause everything to start leaking over time otherwise. No threads and the ability to disassemble means Sharkbite fittings are ideal for this type of pump install.

[Tom M King]

Where is it leaking-at the union joint, or one of the threaded ends. I've use a lot of them, including for that use. If the union mating is leaking, back off a little, and retighten. If that doesn't fix it, replace it.

The PVC unions are one of the few things that are better now than they used to be. I have one on a jet pump, at an old house, that I connect, and disconnect fairly often, to take the pump away, and it's only hand tight without leaking.

With the brass fittings, why not use a brass union? The brass ones have good mating surfaces. I don't know that I have ever used a galvanized union.

[Jerry Bruette]

Is that the inlet or outlet of the pump? I'm assuming that's a check valve between the union and the pump.

[Peter Kelly]

Shark Bite is good now? I wouldn’t be so sure about that.

How's that? I've got a similar Pentair Sta-Rite that I'd mostly installed with Sharkbite fittings, no leaks in 3 years. I wouldn't do an entire house with them but they certainly have their place.

[lowell holmes]

I go to Lowes and Home Depot and pick up the fitting I want. I would put a sealant in the joint if necessary.

[Bill Dufour]

Easy first try is to loosen the union nut and clean the threads. Then apply light oil and retighten. You did not put any sealer on the union threads did you? that is a no no. Does it have brass seals inside the union joint? If not replace it.
Bill D

[Ole Anderson]

A union does not rely on sealant in the union threads to keep from leaking, it is a metal to metal seal. The big nut is just there to draw the two seats together. Any imperfection in the seat will cause a leak.

[Brian Elfert]

I would just use your Sharkbite fittings as your union and get rid of everything on the right side. You probably aren't disconnecting the pump for years anyhow unless they fail regularly.

[Jim Allen]

A union does not rely on sealant in the union threads to keep from leaking, it is a metal to metal seal. The big nut is just there to draw the two seats together. Any imperfection in the seat will cause a leak.

So sealant on the mating surface?

[andy bessette]

so sealant on the mating surface?

...............no!