Advice about leaking plastic joint

[caryc]

Below you see the "out" side coming from a large water filter. The filter is a Nuvo and works very well. The only thing I have a problem with is leaks at the connections.

At the left arrow is that white reducer to reduce the hole to 3/4" pipe. The next brass fitting in the white is 3/4" pipe to male hose end fitting.

Now, about that first white reducer, the filter didn't come with it. I had to buy a reducer. First I purchased a brass one. Then I got to thinking that maybe it would be best to use a plastic one so they would be similar materials. I never did try the brass one. Where you see that left arrow is where I get a drip. I'm afraid of over tightening this thing and cracking the blue casting. The instructions say to use teflon tape at the joints but I just can't get that white reducer to stop leaking. I've tried two different ones.

Is there anything I should be using on the threads instead of Teflon tape? The brass fitting is also leaking at the arrow. Same question...what should I be using to seal the threads?

By the way, I put about four raps on the threads. Any advice would be appreciated.

 

[Fox Mike]

Not knowing what the inside looks like but I wonder if an "O" ring would solve your problem.

 

[Jeepnik]

The blue female is well reinforced to prevent both splitting and stretching. Stretching is more common than folks think, and is the result of over tightening. Once stretched there isn't much you can do about it. The white schedule 40 pvc will stretch easily if over tightened. I would use a very thin layer of teflon paste on both the male and female parts of the connections using a new reducer.

 

[Dan in MI]

Four wraps is a lot of tape, but it still should seal with enough torque.


Options

1) use just two wraps and torque it good.

2) Brass into plastic with no tape "should" cut its own threads when you start getting really tight.
2a) Get both pieces in brass (with tape on the brass to brass) Or get a single step reducer eliminating one of your joints.

3) Find a food grade liquid pipe dope instead of tape.

 

[JFB]

Not knowing what the inside looks like but I wonder if an "O" ring would solve your problem.

tthere does appear to be a groove in the blue (female side)
and
the flange on the white male looks wide enough to have a flat face
BUT
an oring seal normally uses straight pipe thread (not theee normal tappered pipe thread)

 

[Jimbo357mag]

Those plastic bushings are not cast very well. Use a brass reducing bushing and wrap with about 4 wraps of teflon tape. If you still have a leak take off the tape and use a good pipe dope on the threads. If it still leaks clean the threads completely and use a pipe thread sealant but expect that it won't be easy to unscrew. Everything you need should be in any plumbing store.

 

[eveled]

What pressure is it being subjected too? Over 80 psi should have a Pressure Reducing Valve installed on the water main.

Do you have a potable expansion tank on the plumbing system?

Use Teflon tape. Don’t over tighten anything.

I prefer Blue Monster Teflon

 

[blume357]

I vote for pipe dope... seems to work better for me than teflon tape.

 

[powder smoke]

Not sure of this but I am under the Impression Pipe dope is only used on metal fitting!
I no plumber by any stretch! ps

 

[gunzo]

I used Locktite PST #567 for years & swear by it. That doggone tape has been problematic for me in so many ways.

They have other part numbers, but this ^ one solved so many do-overs for me that I quit trying others.

Not cheap, really good stuff rarely is.

 

[mike7mm08]

As suggested thread sealant/pipe dope. It will say right on it if it pvc compatible. Another option that works well if the joint is not subject to constant pressure and want to be able to take it apart easier is basic silicon sealant.

Another thing to try sounds stupid but has solved headaches for me in the past. Get a different brand fitting or buy one from a different store. Can't tell you how many times brand x fitting would leak with every thread treatment trick know to man. Brand z would seal just hand tightened. I am guessing the white fitting is bit off on the specs since both threads are leaking.

I have done lots of work with pvc. Used to install fish tanks and filter systems. Not traditional plumbing so code and the right way to do things was not always followed. Things got a bit creative at times.