#1.5 Pressure Reducing Valves: One, Two, or Too Much?

Which pressure reducing valve is right for your plumbing system? Sometimes PRVs require two valves in series. Hear how the guys get the pressure right in all sorts of applications, from sea to shining sea. 

Transcript

SPEAKER_06 0:01

Welcome to the Ask Coleffi podcast coming at you live from the land.

SPEAKER_00 0:06

Guys, what do we got going on? Plumbing, hydronics, expert insights, and a few stories from the trenches. Whether you're on the job or just along for the ride, we've got you covered.

SPEAKER_06 0:20

Hey, welcome back to another episode of the Ask Calefi podcast with Larry Mo Curly and Champ. You like that? Yeah. Yeah. It worked out pretty good. You knew nothing was coming out of my mouth at all. No. That's awesome. So uh talk a little PRV today. Yeah, PRVs. We have a few models, don't we?

SPEAKER_00 0:44

Yeah. A couple to pick from.

SPEAKER_01 0:48

A couple to pick from.

SPEAKER_00 0:50

Our uh 535, our 536, and our 533. And well, that would be your domestic. And then we got our combo fill line right there.

SPEAKER_06 1:03

Yep.

SPEAKER_03 1:03

573 for 573.

SPEAKER_06 1:05

Yep. And the 5350, which we don't have in front of us right now, but there's one hanging in the wall over there. But yeah, I think uh, you know, we got the 536. The big boy, big dog, uh, for handling some uh pretty high pressures. And then the rest of these are really for you know a standard application, so to speak. Right. Right? So, but uh the 536 is a pretty pretty meaty product.

SPEAKER_02 1:33

Yeah, it is. So it's the piston design versus the diaphragm.

SPEAKER_00 1:37

And that'll take pressures down 150 to 90.

SPEAKER_02 1:41

Yeah, yeah, 90 to 150 adjustable on the high pressure. Yep. Um, and then we do have a low pressure from 10 to 90 psi with a 10 to 90 psi range.

SPEAKER_00 1:52

Yep, and that's a 535.

SPEAKER_02 1:54

Yeah, so really robust for uh you know any application where you know water quality might be an issue or you know, changing water pressures or surging water pressures, that thing's gonna be really robust.

SPEAKER_00 2:06

And we also offer a kit with them both together, yeah, which is new.

SPEAKER_06 2:11

Yeah, that uh a double reduction kit, we'll call it, right? Right, two stage, two stage, two stages of uh of reduction. Matt, I'm gonna pick on you because you're just smiling over there, nodding your head, going, Oh, they're covering it pretty good. I did. We're gonna get through this because I don't have to be involved. Uh-huh. Not so fast. Uh you've probably run across these in the past. I mean, we all have talked to people on the phone about them, and I've been out to visit some job sites where they definitely need double reduction because they're blowing up PRVs. But kind of take us through why you would want a two-stage reduction.

SPEAKER_03 2:51

So I we really don't recommend um reducing much more than two to one in a single stage. So if you've got you know 150 psi coming in, you're reducing it to 70, 75 psi one stage, fine, no problem. Uh, but there's areas where you're gonna have you know 200 plus psi coming in. Um at that point, you want a piston style, like our 536, to take that, you know, knock it in half. Say you've got you know 220 coming in, knock that down to 110 right here, and then you take it the rest of the way down with our 535.

SPEAKER_06 3:27

Yeah, and those are systems you it's usually higher elevation, they're boosting from a lower elevation. There's you know, high rises, yeah. The Carolinas in particular, like near the smokies, there's a lot of boosted systems. So they need 200 psi at the bottom to get it to the top of some of the areas that they're uh they're trying to you know fulfill the the need. So that is where you're gonna run into something like that. Out west is another place, you know, Wyoming, Idaho, that kind of thing, where in the bottom where all the municipal stuff is, they're gonna boost to get it up the hill.

SPEAKER_03 4:05

Absolutely. Well, yeah, same with any basically any store or six, seven, eight-story building plus.

SPEAKER_06 4:11

Yeah, high rises in big cities.

SPEAKER_03 4:15

Yeah.

SPEAKER_06 4:15

Um, I think what's cool about our stuff, and you're never not gonna hear it about from us, is uh the serviceability of all of our stuff, right? Uh you know, even the 533 as a very price competitive model. Uh you can take that thing apart. You are limited with the 533 in you know sizes, your half and three-quarter, that's all you're gonna get. Yep. Um, there's talk of a slightly revised version coming out. We'll see what that looks like in the future here. Uh, but for the most part, we're gonna stick with that same half and three-quarter inch sizes because it's a bargain, really, in comparison to some of the other BRVs out there. Um what I really think is cool about our product, aside from that you can tear it apart and service it and clean it or replace parts, is we have the gauge.

SPEAKER_00 5:07

Right.

SPEAKER_02 5:08

You don't see a lot of our competitors out there with pressure gauges, and um, it's a nice feature to have.

SPEAKER_06 5:14

It certainly is. Um to be able to walk up to a PRV, install it, and then not have to wander back to the truck or forget your test gauge. Test gauge or else on someone else's garden hose bit. Yeah, right. Yeah, it's kind of nice. You'd be able to thread that gauge in there uh and uh and do your setting. Right. Yeah.

SPEAKER_03 5:37

Now one thing to keep in mind too though, um, with with our kit that we saw, our two-stage kit, um, we do have a little thermal expansion device that comes with it that screws in there because in between those two PRVs, if you think of them almost like like check valves essentially, you will have some thermal expansion when there's no flow going through it. Um so there is a device that you've got two ports on the 536, one on one side, one on the other side. Whichever one is more advantageous to have your pressure gauge screwed into, put that one there, and you put the uh expansion device on the other side.

SPEAKER_06 6:13

It's usually the one facing you as you walk up to it, right? Usually, yeah.

SPEAKER_01 6:17

Yeah.

SPEAKER_06 6:18

And that is uh it's a liquid-filled gauge, which is really nice. And when you have high pressure systems, just like you know, our old refrigerant days, yeah, uh liquid-filled gauges don't bounce around a whole lot. So uh with higher pressures, it's nice to have a liquid-filled gauge in there. Yes, it is. What are some of the questions we get? And I say this with a smirk on my face. But when we get one installed out there, whether it's new or it's been installed for a month, I mean, let's let's talk about some of those calls that we get about these. I mean, my favorite is is it is uh it's creeping up overnight, yeah, or it's creeping up after 20 minutes and it's just so happens to be 90 degrees outside. What is going on there?

SPEAKER_01 7:07

Well, any one of them don't don't answer all at once.

SPEAKER_00 7:14

Um well uh pressure creep, uh a lot of times I'll I'll well most of the time I'll tell everybody is take that thing apart and check for dirt and debris in there. Um that valve won't seat all the way when there's dirt, debris, crud in there. And yeah, sometimes you gotta take that cartridge out, take a small little toothbrush, brush around in there, get everything out. Um it's it's funny the last month I would say, maybe a little more, been getting a bunch of calls just because of municipalities flushing out fire hydrants. Right. Yep. Um, I had one guy actually last week call and he just didn't have good flow going through. And he noticed that he turned on his faucet, and here he had just dark colored water coming out for just a split second. And he went down there, he actually called me back. He said that screen was completely plugged. So took it out. I mean, home don't homeowner did it himself. He valved it off, had valves on both sides, which was awesome. Praised the plumber for that, and serviced it and put it back in, up and running, and away you went. So nice, nice, yeah, yeah.

SPEAKER_02 8:25

Yeah, I yeah, I mean you're right though, flushing hydrants will stir up a lot of debris in that system, and that debris pre pressure-reducing valves don't do not like debris.

SPEAKER_06 8:34

No, well, and what causes it is you have a system that's constant under pretty pretty much a steady pressure, and then you take it down, and then everything kind of has the chance to settle out, and then you you increase that pressure, which increases velocity, and it rattles everything loose off the pipes that have been grown, all the biologics, all the rust and stuff that's stuck to the side of the pipe has now been knocked loose and it goes goes downstream.

SPEAKER_03 9:03

Just kind of scours the sides of the walls of that pipe and and deposits it anywhere it can, really. Um, which I mean, that's again with how serviceable these are. It's got that stainless steel screen inside of there. That's gonna catch most of it. You just pop that cartridge out, clean that screen off, put it back in, and you're back in business. Yeah, that works out very well.

SPEAKER_06 9:23

Um to be able to pull it apart. I mean, even more advantageous might be to install a Y strainer if that's a continuous problem, right? Right. Um we know people offer these kitted out with Y strainers, and that's a possibility in the near future here, too, is to be able to we have Y strainers in the catalog, you could easily pick up a Y strainer and put it right in front of it if you have room in the piping, right?

SPEAKER_00 9:47

Yeah, that's always the case.

SPEAKER_02 9:48

Yeah, so debris in the cartridge could show you know a slow pressure creep or it could show a quick pressure creep. Correct. So I mean the debris, you know, could be an indicator of that. I mean, if you do have a slow pressure creep over overnight with no use, um that could be thermal expansion in your system as well. I was just gonna ask. So what else could it be?

SPEAKER_06 10:12

You covered it beautifully, you walked right into that trap. Nice. To uh so go ahead and and care to explain that phenomenon.

SPEAKER_02 10:20

I mean, anytime you add a PRV to a home or have a PRV in a home, you should have an expansion tank, and those are usually installed at the cold side of the hot water heater of your water heater. Um, and what's nice about that is you know, as that heat water heater heats the water, you know, that water expands, which means pressure is gonna increase. So that's what that thermal expansion tank is gonna do. It's gonna absorb that pressure.

SPEAKER_00 10:43

Right. That is always another question I ask too. Yeah, thermal expansion tank on. Oh no. Well, that that would be a good thing to do.

SPEAKER_06 10:52

Yeah, must have. Yeah, um, absolutely. So ours, ours doesn't have the old school feature of that thermal bypass, that little check that is in some of the older models of other brands, where it will allow water pressure to to bleed off back to the inlet side of the valve. Municipalities don't want to see that. I mean, it's not like it's not like you want to you don't want that kind of thing happening in a worst case scenario where you have some sort of back siphoning. There's enough check valves in the system you'd think that wouldn't be a problem, but you better be safe than sorry.

SPEAKER_03 11:32

Well, and I mean another thing is too, if you supposing you've got one that does have that thermal bypass in it, and you don't have an expansion tank downstream, that uh that pressure still has to creep up in your system above the the incoming pressure before that kind of kicks in. So you still have real high pressure in your system at that point.

SPEAKER_06 11:53

Valid point. Very valid point. And that's not prone to failure either, is it at all? No, never. Uh yeah. Uh what about I think we cover auto have autofills a little bit. I mean, they they are a PRV when you're talking of boiler system autofill. Uh they provide water flow into your hydronic heating system or chilled water application in some cases. Uh most of the time they're companioned with a backflow preventer, and it's not uncommon to see a backflow preventer not too far away from a PRV either.

SPEAKER_03 12:32

Yeah, absolutely. I mean, it's backflow preventers. I mean, RPs in municipal water supply, you know, larger buildings, especially. I mean, they're they're pretty much ubiquitous at this point, they're everywhere. Um, and it's for safety's sake. I mean, there's you never know when you're gonna need it, but you really want to have one.

SPEAKER_06 12:52

You need to absolutely yeah, just attend any Union Hall uh backflow prevention class and you see some pretty cool horror stories, don't you? Oh yeah.

SPEAKER_03 13:00

Yeah, it's it's crazy. I mean, it saves saves a lot of lives, to be honest with you. Um, these in this case for a boiler fill, that is required everywhere at every boiler fill. Um, so if you're if you see a boiler fill valve, ours or anybody else's, you should should see a backflow preventer right there, too. Yeah, yep.

SPEAKER_06 13:22

Another one that I hear a bunch about uh that I remember taking a lot of calls about, uh trouble wise, is hey, there's a hammer in my system. Like when someone flushes a toilet or there's a small demand, or hey, the kids love to play with the uh the faucet and turn it on and like to hear the pipe slam. What can what can we rulle darn kids? Darn kids what can we do to prevent that hammering? Because it seems like once it starts, it's a shockwave that just continues on with water pressure flowing until we shut the water off completely and then turn it back on. What is going on with that?

SPEAKER_03 13:59

There's a couple of things that cause that. Um, so one could be your screen is plugged up. Um if it's a if you've had this you know installed for months, a year, years, and it's a newer issue. My guess would be your screen is plugged up. If nothing else has changed in your system, anything like that, that would be the first place that I would check because that essentially is saying like this cartridge is kind of starved for water. So a little bit will come through on a demand, this will open up, and then it'll slam shut, and that can happen kind of bang, bang, bang, bang, bang. Um and you'll hear kind of almost like a machine gun. So if you check your screen, that's all good and clean and everything like that. Um if it's a new install and it's kind of starting to happen right off the bat, my guess would be it's oversized for that application. Right. And it's easy to do kind of because you what you when you're picking it out, what you want to pay attention to is the flow rate that you're gonna be experiencing through that rather than the fitting size or the pipe size that you have. Um it's not uncommon, it's actually pretty common to have a PRV that is one pipe size below the pipe size that it's serving. So if you've got you know a one-inch pipe and you've got a three-quarter PRV in there, that that is very, very common. But it's all it's also hard to for a lot of plumbers to kind of wrap their head around that, myself included.

SPEAKER_02 15:31

Well, you have to remember the municipality has their standard line size they run into a building. They don't know what that building really needs or requires. So they might run a one-inch uh supply line into a building that's maybe two bed, one bath, and sure. You know, that that home doesn't will never see the the flow requirement that a one-inch supply line could provide.

SPEAKER_06 15:54

Yeah, that happens happens often, and it's no different with any other product that we sell just because it's line size doesn't mean you necessarily need what that can carry. Right every application's different. So if you run into something, I think it's smart to call call our tech support. We walk you through as much as we can.

SPEAKER_00 16:14

Yeah, let us know the flow rate, let us know the situation, you know what the building needs.

SPEAKER_06 16:19

Yeah. Great. Well, I think that covers the episode here on PRVs. Uh say it one more time. If you have any questions, give us a call. Give us a call. We love to talk.

SPEAKER_00 16:33

Well, that's a wrap for this episode. Got questions or stories to share? We'd love to hear from you. Reach out and let's keep this conversation going. Don't forget to subscribe and leave a review wherever you live.

SPEAKER_06 16:43

Until next time, stay curious and keep your systems running smoothly.