I have a Zurn PRV that's only 3 years old but appears to have failed (I'm getting a pressure tester to validate). Regardless I want to get the exact model and the nuances of the version I can't tell the differences. Here are some pictures:enter image description here

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I see the following online but difficult to tell the differences:

Zurn Wilkins 3/4" NR3XL Pressure Reducing Valve with double union FNPT connection

Zurn Wilkins 3/4" NR3XL Water Pressure Reducing Valve Integral By-pass Check Vlv & Strainer High Range, Sealed Cage, Double Union

Zurn Wilkins 3/4" NR3XL Pressure Reducing Valve with 2 integral FNPT connection (no union)

Does anyone know the correct version with the information below? I see from the tag it's max 400psi inlet, and a range of 15-75psi. Each end has a threaded union, but I could use a little assistance to make sure. Maybe those different versions are internal features and just would like to understand please.

2 Answers 2


You clearly have Union + FNTP so probably the first one based on fitting type.

The second says union (and does not mention FNTP as well, which yours is using on the top) and the last has no union. The second one is not yours due to the pressure range. Yours is 15-75 PSI that one is 50-165 (high range.)

All appear to have "part numbers" considerably longer than what's marked on the tag, which is a strike against the manufacturer.

Opinionated commentary - unless I could find a rebuild kit at a very attractive price (and most for this model seem to cost MORE than the whole new valve, or nearly as much) I would NOT be rushing to replace one that failed after 3 years (not even, if that 19 35 is a "usual date code" indicating 35th week of 2019, or late August) with the exact same model, unless I was being handed it for free with apologies for the occasional in-warranty failure. That is not a reasonable lifetime.

  • 1
    The Amazon questions on the first option (double union) mention that it came with two unions as separate pieces. Therefore I suspect all 3 have the same valve piece and the only difference is how many unions they include in the box.
    – Khrrck
    May 9, 2022 at 22:53
  • +1 for mentioning the warranty. That should be the first option, especially if there's proof of when it was purchased.
    – FreeMan
    May 10, 2022 at 14:11
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    I'm so with you on the optional commentary. The predicament is I had a plumbing company install it 3 years ago and of course it's out of warranty. They want $500 to replace. I do light plumbing and they set me up well because looking at how it's installed, I don't need to cut or soldier any plumbing. However I don't want to get a different part because if the length changes then it won't be a direct replacement. I'm going to verify the problem today via water pressure (I was told I had 150lbs at the spigot and the PRV had failed). If this is valid I can replace myself for $65.
    – atconway
    May 10, 2022 at 16:03
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    If you can find a rebuild kit for less (a few places did seem to have them for "only" $50 or so, I didn't look terribly hard, though, and was amazed at the places selling them for upwards of $100) you can simply replace the service parts rather than the whole valve. Or you can replace the valve and rebuild this one for "the next time."
    – Ecnerwal
    May 10, 2022 at 16:20

The part numbering scheme allows a customer to order the same base part with a variety of optional components included in the package. At time of this writing, Zurn has a PDF spec sheet for the NR3XL PRV on their web site there. This document describes how the part numbers are built:

<size>-NR3XL<option codes>

The size field indicates the body size and is simply the fractional numbers with all the symbols stripped out. 12 denotes 1/2 inch; 34 denotes 3/4 inch; 1 denotes 1 inch; 114 denotes 1-1/4 inch; 112 denotes 1-1/2 inch; 2 denotes 2 inch.

There are many options; I'll list only some of them. A part number can include multiple options, but not every possible permutation of options will actually be available (some are mutually exclusive or combinations would be non-sensical).

  • <no option> one FNPT union (and, based on my experience, FNPT threaded into the casting on both ends. Union may be used on either end.)
  • C copper sweat union (not clear to me whether there are one union or two)
  • DU double union (like the first part, ie no option suffix, but includes a second FNPT union in the box)
  • DULU with 2 integral FNPT connection (no unions of any kind included)
  • HRSC High Range 15-150 psi

So, to answer OP's question directly: Either the 34-NR3XL or the 34-NR3XLDU will work for you. The -DU will include an extra union which you may choose to discard.

  • Will the 34-NR3XL have at minimum the 1 union required? I'm sorry for the confusion the answer is well laid out, but I'm not 100% on that specific part.
    – atconway
    May 10, 2022 at 16:00
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    I'd guess you can use whichever you want (or is cheapest), as the union you already have will (or at least can) stay in place, and evidently the valve body is exactly the same. So you unscrew the union, then unscrew the valve, and screw the new valve into the old NPT fitting (with new thread dope or tape), then screw the old union fitting onto the new valve. If you end up with some extra union parts, run a copper wire through them and hang them on the pipe near the valve for possible future use.
    – Ecnerwal
    May 10, 2022 at 16:13
  • I'm extrapolating from that comment the unions are re-useable? I didn't know if that was a bad idea or not. Also if it's a standard plumbing part I could always buy one at the store unless it was a Zurn specific version. I did order the cheaper one for $65 vs the $500 the plumbing company that put it in wants to replace it SMH.
    – atconway
    May 10, 2022 at 16:29
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    @atconway Ecnerwal's observation is great. Yes your existing union should fit fine on the new 34-NR3XL body (and yes "34-NR3XL" should also include one union in the package). I wouldn't bet that they're a standard hardware store part though; a union may use whatever size and type of thread its maker likes for the joint between the two pieces. Not all unions are the same there.
    – Greg Hill
    May 10, 2022 at 21:02
  • They are very reusable. Indeed a reason (though it would involve slight replumbing which you want to avoid) to go to "two unions" is that it makes swapping out the valve very quick/easy.
    – Ecnerwal
    May 11, 2022 at 22:54

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