avoiding corrosion issues w/ lead-free brass

[RustyShackleford]

We recently bought a house in a small town with a municipal water system. They treat with chlorine (but claim not to use chloramine). I'm concerned about corrosion, particularly in the lead-free brass that's becoming so common; I know there's DNZ (dezincification-resisitant) brass, but not sure how well it works.

I've re-done some stuff already (because of old brittle PVC in a freeze-prone basement) with PEX. I used these stainless-steel crimp fittings: https://www.supplyhouse.com/Stainless-Steel-PEX-Crimp-Fittings-35095000

There's some more stuff I'm redoing to deal with a failed PRV (pressure-reducing valve) and to add pre- and post-PRV gauges. The PRV was badly corroded, but I know of no stainless or plastic versions. I'm very tempted to replace the shut-off valve with a PVC one; somehow plastic seems "wimpy" for the main feed to the house, but I can't think of a real reason not to go that way. The very mountainous town has a zoned gravity-fed system; we're a little more than 200ft below our tank, so the pre-PRV pressure in the shutoff valve is 100 psi or so (set pretty much by the laws of physics).

Thoughts ? TIA.

 

[Twowaxhack]

I use those same fittings with Rehau pex.

I wouldn’t use a plastic ball valve. Use stainless also made by Boshart and sold at supply house.

Just get a brass PRV and install unions so it’ll be an easy swap when it craps the bed.

 

[RustyShackleford]

Just get a brass PRV and install unions so it’ll be an easy swap when it craps the bed.

So, to be clear, you suggest getting THIS version of the bedly-corroded PRV that's there now:

https://www.zoro.com/zurn-valve-34-pipe-size-double-union-fnpt-34-70xldu/i/G3784809/
... and then when I need to rebuild or replace it, I can remove simply by unscrewing the two unions from the PRV body itself ? And the only thing that's necessary to make a seal is two rubber washers where the unions screw onto the body ? So. I don't have to mess with any of the NPT or PEX connections.

 

[Twowaxhack]

So, to be clear, you suggest getting THIS version of the bedly-corroded PRV that's there now:

https://www.zoro.com/zurn-valve-34-pipe-size-double-union-fnpt-34-70xldu/i/G3784809/
... and then when I need to rebuild or replace it, I can remove simply by unscrewing the two unions from the PRV body itself ? And the only thing that's necessary to make a seal is two rubber washers where the unions screw onto the body ? So. I don't have to mess with any of the NPT or PEX connections.

Correct, but hopefully the new one will last.

 

[RustyShackleford]

Actually, pleasant surprise, I found out Zurn makes a unit with two PEX unions, because it was listed at a vendor (but not a Zurn's website):

https://www.plumbmaster.com/zurn-wilkins-34-70xldupex-3-4-70xl-series-double-union-pex-prv/p/59274
... the picture being obviously wrong.

So I can go from shutoff to PRV in PEX (with a tee for pre-PRV pressure gauge). And then remove the outlet PEX union and put in a 3/4" MNPT to 1" PEX male adapter, since I'm running 1" PEX after the PRV (because it's a 40ft run to the house-proper and with 3 bathrooms and a kitchen I want to allow for 10-12 gpm).

So I'll only have one union, but that still allows me to remove the PRV without redoing any PEX, by undoing the inlet union and then unscrewing the PRV from the male adapter on the outlet.

 

[Twowaxhack]

Actually, pleasant surprise, I found out Zurn makes a unit with two PEX unions, because it was listed at a vendor (but not a Zurn's website):

https://www.plumbmaster.com/zurn-wilkins-34-70xldupex-3-4-70xl-series-double-union-pex-prv/p/59274
... the picture being obviously wrong.

So I can go from shutoff to PRV in PEX (with a tee for pre-PRV pressure gauge). And then remove the outlet PEX union and put in a 3/4" MNPT to 1" PEX male adapter, since I'm running 1" PEX after the PRV (because it's a 40ft run to the house-proper and with 3 bathrooms and a kitchen I want to allow for 10-12 gpm).

So I'll only have one union, but that still allows me to remove the PRV without redoing any PEX, by undoing the inlet union and then unscrewing the PRV from the male adapter on the outlet.

You sound like you know what you’re doing. I trust you

 

[RustyShackleford]

What is generally considered the correct tightening with a union ? I believe the ones on the Zurn 70 have rubber washers kind of like a garden hose.

 

[RustyShackleford]

Here's a picture of the 3/4" double-pex-union version of the Zurn 70 that I'm buying.

 

[Twowaxhack]

What is generally considered the correct tightening with a union ? I believe the ones on the Zurn 70 have rubber washers kind of like a garden hose.

I just snug them down tight, they seal well. Very similar to a tankless water heater valve set, they also have a union with rubber washer.

 

[breplum]

Pretty much the only readily available double union PRV, so it is all we use.
Once in a while I get one that will allow adjustment way over 100 psi, but behaves well when adjusted to 85.

 

[RustyShackleford]

Actually, the picture shows the expansion-PEX version (note F1960 at end of part#, after DUPEX).

 

[RustyShackleford]

What is recommended way to go from PVC (coming in from street at about 100 psi) to PEX ? Could use male adapter solvent-welded to PVC pipe along with female PEX adapter screwed onto it. Or Souix Chief makes a one-piece solution: https://www.supplyhouse.com/Sioux-Chief-645X3P-3-4-PVC-x-3-4-PEX-Crimp-Straight-Adapter-Lead-Free

I prefer the former, because of corrosion; I'd use the Boshart stainless line for the female adapter.

 

[Twowaxhack]

What is recommended way to go from PVC (coming in from street at about 100 psi) to PEX ? Could use male adapter solvent-welded to PVC pipe along with female PEX adapter screwed onto it. Or Souix Chief makes a one-piece solution: https://www.supplyhouse.com/Sioux-Chief-645X3P-3-4-PVC-x-3-4-PEX-Crimp-Straight-Adapter-Lead-Free

I prefer the former, because of corrosion; I'd use the Boshart stainless line for the female adapter.

I’d use the adapter in the link you have posted. Unless you have acid water…….

 

[RustyShackleford]

I’d use the adapter in the link you have posted. Unless you have acid water…….

It's got chlorine in it. And like I said, the parts in the old PRV I took apart were all ate up.

 

[Twowaxhack]

It's got chlorine in it. And like I said, the parts in the old PRV I took apart were all ate up.

I’d use the souix chief copper x pvc adapter.

Chlorine and copper can play together. You want the ph between 7-8

I wouldn’t use an all pvc male adapter unless it was outside.

 

[RustyShackleford]

I’d use the souix chief copper x pvc adapter.

Chlorine and copper can play together. You want the ph between 7-8

I wouldn’t use an all pvc male adapter unless it was outside.

It'd be a PVC male adapter with a stainless female PEX adapter screwed onto it.

But I'll use the Souix Chief thing, like you say.

 

[Twowaxhack]

It'd be a PVC male adapter with a stainless female PEX adapter screwed onto it.

But I'll use the Souix Chief thing, like you say.

Right, and I wouldn’t use a plastic pvc mip with a stainless female screwed over it inside a residence. Ever…..

Pvc threads are a big time weakness. It’s a very common failure point.

 

[RustyShackleford]

Pvc threads are a big time weakness. It’s a very common failure point.

Ah, good to know, thanks for the tip. Plenty of 'em in the house now, I feel vindicated ripping this stuff out and replacing with PEX.