Help understanding NPS vs NPT connections for shower head and diverter

[DuaneK]

I'm planning a bathroom tub/shower update and I can't figure out why thread types change and how to deal with it correctly. My question is about a Moen diverter valve that connects to the shower head pipe. By the spec sheet it has an NPT on one side and NPS on two sides. From the picture on their web site it shows a union type NPS coupler (face seal) to the pipe from the wall. This part it confusing because I'm thinking the wall pipe is an NPT on both ends (one into the drop elbow inside wall, and the other into the shower head). It seems that an NPTM pipe to an NPSF shower head is OK and also NPSM to NPSF to a spray head hose is normal. Am I understanding this correct? I realize any connection inside the wall should be NPT.

 

[Terry]

The union side will have a washer that seals.
You're right about the tapered threads on both sides of the shower arm.

 

[Sponsor]

 

[DuaneK]

That was fast Terry thanks, So just to make sure I understand an NPSF can connect to a NPSM or NPTM. Again if they are outside the wall .

 

[Terry]

That was fast Terry thanks, So just to make sure I understand an NPSF can connect to a NPSM or NPTM. Again if they are outside the wall .

Yes.

 

[DuaneK]

To go another step because I prefer the diverter closer to the wall. If I had a short NPT nipple that just passed the trim ring. Then I went to the diverter. I would just need a female/female NPT coupler to transition to the shower arm. If I can find a coupler in brushed nickel?

 

[Terry]

To go another step because I prefer the diverter closer to the wall. If I had a short NPT nipple that just passed the trim ring. Then I went to the diverter. I would just need a female/female NPT coupler to transition to the shower arm. If I can find a coupler in brushed nickel?

That would work too.

 

[DuaneK]

Thank you for taking the time to help me! I think I know what I need to do now.