I recently purchased a Phyn Plus 2nd gen smart water leak detector. I arranged for a plumber to install it but the plumber hit a problem where some adapters were missing. The problem seems to be that the Phyn Plus has 1" NPSM male threaded ends, which may not be compatible with other pipes.

The plumber confirmed that I need a couple of: SWP4521010 LF Brass Straight Water Meter by Male Threaded Adapter, 1″ NPSM x 1″ NPT adapters. Phyn indicates they need to be manufactured by Uponor.

My problem is I can't find this item using the full code, starting with SWP. However, if I search just for 4521010, I quickly find this:

enter image description here

Notice the SKU starts with LF but the digits are the same. The title includes 1" NPT and it's from uponor, but it says 1" ProPEX instead of NPSM.

My question is - Is this part I'm looking for?

  • 4
    You're paying the plumber but he's not heading down to his favorite plumbing supply shop to pick up a specialty part that he doesn't have on the truck? Honestly, he's going to bill you for the part and mark it up to make a profit, if he's not interested in that, I'd consider a different plumber. Also, I wonder what's so special about the Uponor part that it has to be that brand and none other...
    – FreeMan
    Commented Feb 4, 2022 at 13:43
  • 1
    I'm sure this is resolved by now, would you please write up an answer sharing what you did? Also, I'm surprised that I didn't also recommend that you ask your plumber if you'd found the right part. Of course, with my previous comment, I wouldn't put that much faith into the guy...
    – FreeMan
    Commented Jan 27, 2023 at 14:11

2 Answers 2


No it's not correct. The correct one seems to be hard to find. The one you're looking at is for pex which is plastic pipe. Your plumber requested 1″ NPT which is copper pipe thread not pex.

I ended up finding a 3/4" NPT to NPSM adapter. It restricts the line but it shouldn't really matter unless your house is very large.

3/4 in. NPT Brass Water Meter Coupling Complete with Gasket, 2-1/2 in. L with 1 in. NPSM

  • Is there something in the part number provided that tells you that the OP does not have PEX plumbing? If so, please share that info (edit it into your answer) as it would be helpful to others. If not, how do you know that a PEX fitting won't work for the OP?
    – FreeMan
    Commented Jan 27, 2023 at 14:09
  • 1
    Yes his plumber requested 1″ NPT which is pipe thread on copper
    – MrPHP
    Commented Jan 28, 2023 at 18:47

I suspect that the Uponor part is a recommended/qualified part rather than a requirement. As MrPHP noted, the PEX adapter you found is the wrong part.

The key is that your Phyn device apparently uses 1" straight threading (NPSM or National Pipe Straight (threaded) Mechanical), which requires a rubber gasket inside the female fitting to make a seal against the face of the male fitting. Most plumbing (in the US at least) will have tapered rather than straight threading, allowing thread-to-thread sealing just by tightening, without a gasket. Thus, the other end of the adapter is spec'd as NPT (National Pipe Taper (threaded)).

Here is a generic adapter found on a shopify site to show what your plumber was recommending:

enter image description here

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