Ask Caleffi
Welcome to the Ask Caleffi podcast series, now featuring our powerhouse tech team! Join Cody, Ryan, Matt, and Dan as they dive into the tricky heating and plumbing challenges they tackle every day.
These field experts share real-world insights to help contractors navigate even the toughest jobs with ease. Count on the team to keep things lively, mixing professional wisdom with the entertaining, relatable stories you’ve come to love.
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#1.9 Separation Simplified: What are the Best Practices for Keeping Your System Clean and Healthy?
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Ever been haunted by "ghost flows" or a radiator that won't stop clicking? In this episode, the team breaks down separation—the art of managing air, dirt, and pressure to ensure your system actually behaves.
Hydronic systems fail when air bubbles block heat transfer and magnetite turns ECM pumps into debris magnets. We dive into the "gotchas" of piping placement and why the right hardware is the only way to protect your boiler's efficiency and your sanity.
In this episode, you’ll learn:
- The Air War: Why air is the enemy of heat transfer and when to ditch the scoop for a high-performance separator.
- Hydraulic Peace of Mind: How to prevent pump conflict so your circulators don’t fight each other.
- The 4-in-1 Advantage: Why the SEP4™ style device simplifies piping and speeds up installs.
- Direction Matters: How backward piping drives unwanted mixing and kills efficiency by boosting return temps.
- Magnetite & Modern Pumps: Why magnetic separation is now essential survival gear for ECM circulators.
- Water Chemistry: Why separators need a wingman in the form of high-quality inhibitors.
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Welcome From The Lab
SpeakerWelcome to the Ask Caleffi Podcast coming at you live from the lab. 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.
What Separation Really Means
Speaker 1Hey there, welcome back to another episode of the Ask Caleffi Podcast. We're here hanging out in the lab, gonna talk a little bit about separation. Separation's a pretty broad term, would you not say? I mean, there's multiple ways of separating. A lot of different types of separation options there. We got to keep them separated. Absolutely. Keep us separated. No, they can't keep us separated. That's why we're all here. Um, we got a few different options here on the table, don't we? I mean, we've got an air separator, which we know air in hydronic systems is terrible.
Speaker 2Right.
Speaker 1Right? Yep. Got to get rid of it so we can actually conduct heat and uh and get fluid movement through the system because we know that circulators don't move air very well. Also help keep the system clean. Exactly. Um, dirt separators, right? Keep the debris out of boilers. You get a an existing system that maybe had old cast iron boiler in it, has cast iron rads, or just a mix of different piping and different materials. It does break down over time, creates rust, um, ferrous material, things like that.
Speaker 2You need a dirt separator in there to protect high efficiency boilers that you're gonna put in, especially with those new heat exchangers, high efficient heat exchangers, small little ports in them. Yep, tidy little passageways. Yes, exactly.
Speaker 3Oh, you're up in a hurry.
Speaker 1Yeah, they do. Yeah. Then we have that little monster over there. Um, the air dirt separator, which uh that it's always a hot topic of debate. What should I use? Should I use an air? Should I use an air dirt? Should I use a dirt? The answer is yes to all of that. Uh, but the air dirt has more of a a niche area where we would like to see it, in my opinion. I mean, maybe you guys have a different opinion of it, but I'll explain my stance on it in a few minutes.
Why SEP4 Beats Closely Spaced Tees
Speaker 1Then over here we have a hydraulic separator. Actually, it's our set four, which allows you to do hydraulic separations, so pump decoupling to prevent any kind of uh, you know, conflict of pump.
Speaker 2Yeah, pump conflict across the two sides of the system.
Speaker 1Yep. Right. You have an air coalescing mesh on top, a really nice air vent on the top, and then you have coalescing mesh in the bottom with a magnet that helps catch any of the ferrous material. So we're doing four different things there. And then a place to bleed it off to.
Speaker 2Yeah, so you highlighted our CEP4. Um, we're gonna have two options in the hydraulic separators. We'll have just our 548 series, which is standard hydraulic separation. You know, you may get some air and dirt removal as a you know, byproduct of that velocity drop, but not designed to separate air and dirt. Yeah. Right. And I mean, if if I'm picking, I'm getting the SEP4. Because it's it it's four and one. It's everything. Right. It's uh why add any more components? You can put the one product in and walk away. Yeah, you're exactly right. I mean, I talked about the hydraulic separator. You know, that's gonna provide hydraulic separator separation, but you're still gonna need air to add air and dirt separation. Right. Where you're right, right here with four connection points, you have all of that in one. Exactly.
Speaker 1Exactly. It takes away a lot of guesswork. And if we can just kind of keep beating the hydraulic separation drum here, um if we were to do closely spaced T's, if they're not done correctly, if they're not spaced correctly, um, you know, before and after a set of elbows, distance between the T's, not generously sized, you're gonna run into all sorts of issues, right? Yeah, you'll get pump conflict.
Speaker 3Yep, it's not gonna work. This is pre-designed, pre-engineered, it's kind of plug and play.
Speaker 1Yeah, and there's no minimum distances from elbows. Um, you can come in with an elbow, a street elbow if you wanted to. Um street elbow in, street elbow out. Um it makes it a really simple um it saves room, saves connections. You know, if we were to do the math, if we're doing an air and dirt separator and we're doing the the closely space tease, that's that's 10 connections. Right.
Speaker 2And that's probably the biggest question I get is how far or how long does the pipe have to be coming off of it? Nothing. Nothing. I mean, you could put four street 90s right into this thing, and you're good to go.
Speaker 1And they and people want to know, well, why is that? Why is that the case? Why do we not need a piece of straight pipe for laminar flow like we would on a Takeover or whatever air scoop, right? Right. Because we have a very wide barrel there. It's usually a three to one difference from the connection size. So if it's one inch coming in, it's a three-inch barrel or better. Right. So you have a reduction in velocity and the fact that we have coalescing mesh there, no matter where the bubbles are, if they're in the bottom of the pipe or the side or the top, it's always going to be able to grab those bubbles. It gives a surface to for them bubbles to cling to where an air scoop, there's nothing in there. There's a couple of little little veins that if you're lucky, most of the bigger bubbles due to gravity and reduced velocity, provided you have that 18 inches of straight pipe, right, to make it laminar gives it a chance to come out of the elbow and you know, float up and kind of hug the top of the pipe. You don't have to worry about that with this. Right, right.
Speaker 2And I mean, a lot of guys that go, well, it's kind of big. How do I get it into a system? We got a tight, tight area. Well, you can go right off with street 90s, street 45s, whatever you need. Well, and you're right, it is larger, but when you start looking at using closed space T's and all the connection by the time you're doing it, you need and and straight lengths of pipe, um, and then adding in dirt separator and an air separator on top of that, you you you're starting to grow the footprint of that system. I mean, I I think when you look at it from that point, to be able to come right out of your boilers into one side, out of the other side to your system and have that four-in-one protection, it probably ends up taking up less space. It does, it saves wall space for sure. Wall space and time. Yeah. Definitely.
Speaker 1It's it's a win-win all the way around. So, you know, look at what your labor is worth. If you took the time, if you're a solder guy still even press, I mean, that's more press joints. And if something got messed up with uh with your press in closely spaced tees, now you gotta cut all that out.
Speaker 2Yeah. I mean, and we're showing our one inch here. I mean, we have them in flange commercial products up to 14 inch. Yeah. Yeah. I mean, we we make some pretty big stuff. I I think I might have a picture of you riding one with a cowboy here. Yeah. I know you don't have a picture of that. That's a fixture I know doesn't exist. Oh, it might.
Piping Direction And Efficiency Traps
Speaker 3Uh and one question that we do get um quite a bit is on the sticker or on the instruction sheet, it it shows, you know, supply flowing from right to left, return from left to right, or vice versa. Um, people will be like, is that necessary? No, it can go either, you can you know, flow in either direction. One thing that is important though is that the supply is on the top, return is on the bottom. That's gonna be the best, most efficient dirt and air separation um within within that.
Speaker 2Yeah, yeah. That and then your your primary is one side, secondary is the other side, or boiler or building, however you want to classify that. Yo stays consistent on on the same side of the of the separator. Sure.
Speaker 1And the other question we would get an awful lot too is after the fact, of course. Um, hey, I pipe the supply in the bottom and the return in the top. Will it still work? It will still decouple the pumps. Yes, it will do that part of it, but you will have some stratification and mixing going on in that barrel regardless. So all your warmer, hot or hot water going in through the bottom will then rise up, mix in, and and it'll mess up your return temp. It'll boost your return temp into your boiler, which will then in turn affect its efficiencies. It won't work as efficiently as it should.
Speaker 3Well, plus, I mean, the air separation, obviously, that that works by us at the highest temperature. Right. So if you've got the highest temperature coming in through the bottom and those bubbles are separating out, rising up, now they're getting shot back out. And back to the system before they get vented out.
Speaker 1Yep. Exactly. So if you ever have questions, you get one of these as your first one, we'll we'll always be happy to answer those questions if you call in. Um be curious and ask us questions if you don't know. Yeah. Yeah, that's what we're here for. Yes.
Air Separator Placement And Service
Speaker 1So from that, we're gonna talk about uh air separators, right? We kind of talked about it with a with an air scoop, but I mean this is a better alternative to an air scoop is an air separator, like this 551 we got here. Uh coalescing mesh in it, and uh super serviceable air vent, and you know, one inch all the way up to 12 inch, 14 inch. It's uh 14 inch, yeah. Yep. For for our Canadian viewers, uh only 12 inch. But uh for uh for the rest of us, uh we we have the ability to make a 14-inch uh air separator. So I think just the feather in our cap with this stuff is serviceability. Uh you'll always hear me tout serviceability. All of us do. We can take the air vent apart, we can clean it if it starts to leak, because air vents shouldn't leak water, they should only let air out, right? Right. But it's easy enough to pull it apart and clean that needle valve assembly out. And if you can't get it cleaned out, more than likely the seal might be dried out. You know, if you're running a glycol system, glycol's hard on stuff. Very hard, very hard.
Speaker 2It's hard to get air out of glycol.
Speaker 1Yeah, it's hard to get air out of glycol because it's so thick, you know. Um, and two, it just it's hard on rubber parts. It is, and it finds its way out of everything, finds its way to escape. Yeah. So slippery, it's a slippery little devil.
Speaker 3Um really nice that they've got the a half-inch female connection to on the bottom for a fill valve, expansion tank, yep, all that stuff.
Speaker 2And also a pinned float um in the air vent, the discharge assembly. There's a a pin in the center of that float that keeps that float moving up and down. You know, if you happen to get it installed a little out of a plum, uh that float won't ride against the side of the body and get hung up.
Speaker 1Yeah, it doesn't mean we should you should forget your level. But if you happen to, um if you get it pretty close, it'll still somewhat work. Um yeah, it's nice that it is pinned and it doesn't allow it to float or stick to one side or the other of the body. You'll always have that float-centered and arrow be able to get around it pretty well. We sell the rebuild parts for it. So the top, the entire top or coalescing mesh, it's all o-ring sealed together. You don't have to worry about gaskets when you do pull them apart to service them or replace parts. They always have captured rubber o-rings in them.
Speaker 2I think that stays on track with you, most of the Clefy products is that again, it's serviceable. We we have the the service and maintenance parts and replacement parts. Uh like all of our products, we focus on being served on serviceability.
Speaker 1Yep. And you called it out earlier with the SEP4, but where is the ideal location for a an air separator?
Speaker 3The hottest point and the lowest pressure point in the system. So ideally, this would be on the supply upstream of a circulator.
Speaker 1Yep, yep. You can go downstream of it too, but if you what you run into in some cases, if your your circ is oversized, which happens a lot, and it's really close to the inlet side of that circuit, you can create a problem with that circu actually pulling a negative, a pretty hard negative enough to actually pull that float down, and it'll suck air in. So we do make a uh a check valve cap for it. So an anti-suction cap, which is really nice, but that's kind of a boo-boo fix. And the better the the better fix for the boo-boo would be to cut the boo-boo out and start all over. But you know, time is money, so sometimes you have to do that. Um, but yeah, that's that's the uh the air
Dirt Separation And Magnetite Problems
Speaker 1separator. Now we have the dirt separator right there. You got that nifty uh clear version there.
Speaker 3Um yeah, this is a you can take a look inside. This is our our dirt make pro. Um these have two magnets, so you've actually got one magnet right in the flow path that will hold all kinds of any any ferrous material until you you know shut it down, pull that pin, everything obviously falls down to the bottom. We've also got another magnet that any ferris material that runs into this mesh and doesn't get stuck to that magnet will be held in place here until you pull that when it's time to purge it down, clean it out.
Speaker 1Yeah, that's the safety belt and suspenders approach to removing ferris material. But what people don't realize, I mean, everybody there was a big push to put magnets in systems, right? And reason being pumps, variable speed pumps, variable speed circulators. Those are a wet rotor magnet. So if you don't have a magnetic dirt separator, you actually do if you have a variable speed pump. It's a really expensive one, very expensive, right? I always tell the story that like one of the one of my easiest service calls on a hydronic system is we did we did a a job for a guy that uh he had an addition, he added some in floor, and it was an existing system. I don't think anybody really looked or paid no mind to it, and this is before we were installing magnets and anything. Right. Um put a variable speed, was a nice uh Grunfuss alpha pump, I think it was an alpha two or whatever. Put it in there, and um, I get a phone call on a Saturday. Yeah, you guys did this work in April, it's October, it doesn't work. Long story short, go over there. I don't have that pump on the truck. I take the four bolts loose, I pull the cartridge, and it's covered in that red stuff. It's just not not ideal. And of course the homeowner's sitting there watching me on the bucket or on the chair. Yeah, on the chair. Oh no, he was standing and fuming. So um, shop rag to the rescue, wipe all the stuff off of it, uh put it back in, did a little purge, got it going, and it ran perfect. Well, why is that in there? Why did you guys put red stuff in my system? We didn't, it was in there. No, no, it was fine. Well, it was fine because you had you did not have variable speed pumps until we put this one in. Right. This one's this one attracted all that debris out of the system.
Speaker 2So it's amazing how much stuff will get in your hydronic system. Yeah. Yeah. It's well, you have to you have to remember that magnetite is almost like a powder. So it's like you call it boiler ink or you know, that black magnetite hematoner. Yep. Um if you dry that out, it's actually a very fine powder. Like soil. Core consistency. Yeah. Yeah. So that's where the magnetic separation is important. And you're right, variable speed pumps will catch that. Uh boiler heat exchangers, you know, radiators, anywhere in the system that you have a velocity drop, um, that magnetite will settle out in.
Speaker 1Yeah. Pastine rads are great little spots for stuff to hide, and you can't put enough pressure through them things with all the ripples that are in that surface. The larger passages that bot that velocity drops. It does, it drops big time.
Speaker 2Radiator. Yeah, perfect dirt separators. Yes, yeah. Radiators. Yeah, they are. Well, we always say if you don't have a dirt separator, your system becomes one. Yep, yep.
Speaker 1Exactly. Yep, all the nooks and crannies. Well, I I think we covered air separators, dirt separators, hydraulic separators with air and dirt, and now we have the air dirt.
Air Dirt Separator Best Use Cases
Speaker 1So where would we put in an air dirt? That is number one question that we get about that product. Where do we put it? I had a supplier in Colorado that I went and visited, and he's like, Oh, yeah, we love Cleffy products. Okay, you don't sell a lot of them, but that's cool that you love them. Um what one do you sell the most of? I'm just curious. Oh, the 546. Well, why do you sell the 546? Well, because it's an air and a dirt, and our plumbers just want one thing and it's simple. Okay, where are your plumbers installing these on boiler systems? Well, I don't know. They just install them. Well, uh let me let me ask this question. Where does dirt where where do you what do you want to protect? Well, we want to protect the whole system. Okay, where is where's the best place to remove air from the system? And they just kind of looked at me because they're counter guys. I said, the best place to remove air from a system, a hydronic system, a heating system, is the hottest water with the lowest velocity. Usually in the supply, you know, up here in farm country, we like to put our our cast iron boilers in the basement, and we come up right off of it and we we put that air separator right there. Exactly. On the supply before it goes out to any baseboards or radiators or whatever.
Speaker 2Yep.
Speaker 1Highest temperature water, highest temperature water that's gonna you're essentially boiling, right? It may not be the right term, but simple term, boiling and creating bubbles right there. Right. Okay, that's where you're gonna remove the the air. So now I see, you know, the squirrel's turning the wheel a little bit. I said, but you want to protect your boiler, right, from any dirt and debris coming back. And you want to protect a variable speed pump if that's what they're using. And they just kind of got quiet.
Speaker 2Well, and it's gonna do that, but it's gonna do it from the supply side. It will, but but it's too late because it's already caught in the boiler. I agree. You know, yeah, I look at a system that has an air separator on the high side where the water's the warmest and you're gonna get the most efficient air separation, uh, and then a dirt mag on the return side before the boiler and the pump to protect the pump. I mean, you're gonna get both out of that, but it's hard to get it in that ideal spot for either one.
Speaker 1Right. So I said you should be selling them, you know, you should be talking to these guys about putting an air separator on one on the supply and a dirt separator on the other. That device there works as like a band-aid. Right. You know, say they got an air separator in, but they figure, well, we're gonna do double duty, we're gonna do some more air removal. I would still put that on the return anyway. Yeah. On your boiler system.
Speaker 2Those are fantastic for chiller systems, though. Exactly. That's the perfect application because on the chiller system, you know, the return side before the equipment and the pump is where you're gonna want to do your dirt removal, but that's also where your water temperature is the warmest and you get your best air separation. Yep, that's the warm side. Yep. So that's really the best application for an air dirt, is in a chiller.
Speaker 1Yeah. That's where you can get that in the ideal spot for bolt.
Speaker 3Right.
Speaker 1Well, and I think that's I mean, that's the best option to get rid of any materials, not just ferrous materials, too. I'm like, we look at this has got coalescing mesh in it. Yeah, it's gonna help you remove that ferrous material, but let's be honest, not all jobs are neat and tidy, right? You get you get an apprentice, you get an apprentice that you know likes to put they're under the mindset a little is good, more is better with flux and solder or thread tape. I mean, how many of these have we probably blown off and gotten thread tape out of? Yeah, you know.
Speaker 2Well, that coalescing mesh is gonna take care of the more of the non-ferrous material. Exactly. The magnets there for the ferrous.
Speaker 1Yep. Yep. So you kill two birds with one stone then you have all that in there. Um keeping systems clean from you know the solids, that's what these devices are for.
Water Quality And Fluid Treatment
Speaker 1We get other questions about hey, what about water quality? Totally different animal. I mean, that's another approach that has to be taken. That is treatment of the fluid, that is putting in good fluid, like the mineralized water, but then you still got to add inhibitors to it because nice, clean, good water looks to rebalance itself. When we're talking, you know, RO is the most aggressive, right? Like you would never put RO in a system because it'll eat it alive. There's a reason it's piped in plastic and nothing, nothing else, right? Right. Um, but demineralized is less aggressive, but still aggressive enough where it's going to try and leach minerals out of any components that are in their cast iron volutes, um, iron-bodied separators, you know, brass, brass will give up some, some grades of stainless will give up some. So it'll always work to rebalance. Yep, it always works to rebalance. Doesn't mean it's bad water, it just turns from nice clear liquid to kind of a rusty tea color. So keep that in mind. If you got hard water and you're putting it in there, you get all the solids out, great. But if you have a boiler that over time all of a sudden has a lot of kettling going on and heat transfer is not good, that's usually that usually means that there's not so good of water quality in there.
Speaker 2Yeah, I mean, water quality is your number one first starting point. If you start with a clean system and you put in water with you know very high quality water, these devices are there to protect and maintain the system from there. But let's let's start fresh and start clean. You know, if you are in an old system, um retrofitting an old system, these will be there to help clean that up. Right. And water quality will keep all your components running good. Yeah. It's a big uh it's a big thing. It is a big thing. It is. Little did we know. Yeah. Exactly. Whether it's a small residential project or you know large commercial, I mean Caleffi has you protect it. Right. Got a product to to fit your application.
Speaker 1Absolutely. And uh if you need help, give us a call. Yeah.
Speaker 3We're here.
Speaker 1We are. Thanks everybody.
Speaker 2Thank you. Yeah, everybody. Talk to you later.
Questions And Closing
SpeakerWell, 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 listen. Until next time, stay curious and keep your systems running smoothly.