Moen tub spout impedes flow

[RYAN OHARA]

I purchased a Moen kit to replace everything in my shower. The previous parts were old and corroded causing the tub spout to leak significantly.

Now that I have installed the kit (though not the handle yet) the tub spout is not exactly perfect. While it no longer leaks during a shower, the inverse is now true: the shower turns on when I'm trying to fill the bath.

The spout has a plastic piece inside on a metal rod that slides up and down; it seems like the plastic piece is too big. Even when it's in the default down position to not engage the shower, the water pressure builds up and runs out of the shower head.

Has anyone seen this before? I intend to call Moen tomorrow about it during their business hours. I am pretty stumped on how to proceed.

 

[Terry]

How was the spout installed? Was it a slip fit to copper?

 

[Sponsor]

 

[RYAN OHARA]

Hey Terry!

It screwed onto the pipe.

 

[Terry]

Hey Terry!

It screwed onto the pipe.

Normally as long as the pipe leading to the spout is full sized pipe nipples you're fine. It needs to be free flowing with restrictions, and that way the water isn't pushed up to the shower head.

 

[RYAN OHARA]

It is full size but it was not quite long enough to fit this tub spout as it's longer than the previous. I tried to replace the pipe itself but it seems soldered behind the tile wall.
Would this adapter cause what I am seeing? I needed it to span the 1" gap since I can't easily replace the pipe. https://www.amazon.com/dp/B07RZS9KHL/ref=pe_386300_442618370_TE_dp_i1

Is it possible this spout was poorly manufactured and the diverter is causing a problem?

 

[Terry]

I don't think that adapter was the problem. Sorry. It is strange that it's doing what it's doing.

 

[WorthFlorida]

Was the depth of the threaded connection inside the old spout the same as the new spout? Did you use any tape around the threads? It shouldn't have any.

If the new spout easily threads off, remove it and then run the water to be sure that it is something with the spout that is causing the issue.

This will show you the three parts to the internals of a moen spout and how to disassemble it.
https://solutions.moen.com/Article_Library/Replacing_a_Tub_Spout_Diverter_Gate

 

[RYAN OHARA]

The threads were the same. I did use some tape - perhaps that is the problem?

That link was super helpful. Thank you! I just took it apart and it's still doing it! Guess I will be removing this spout to further investigate.

For my own edification, why should there not be tape on these threads?

 

[RYAN OHARA]

Solved! Having taken the spout off just now I found the problem.

The spout itself was totally fine. Just behind behind it I found this little white o-ring.

Any idea what that is? It was restricting the water flow to a small hole but I don't know from where this came.

I guess I can just reassemble without that and it should work.

 

[WorthFlorida]

The threads were the same. I did use some tape - perhaps that is the problem?

That link was super helpful. Thank you! I just took it apart and it's still doing it! Guess I will be removing this spout to further investigate.

For my own edification, why should there not be tape on these threads?

Sometimes people get tape over the front face of the threads and may have partially blocking the flow. Tape on the threads is OK but a nylon female coupling really doesn't need any.

 

[RYAN OHARA]

I'm still at a loss for what this white rubber piece is... But the spout works!

Thank you everyone. I greatly appreciate your help Florida-man and Terry.