Eric Johnson (00:00)
Welcome back to Boiler Wild. My name is Eric Johnson. On this podcast, I talk about boiler industry topics as well as personal development. We shall always strive to get better. I strive to get better every single day. Some days I fail, some days I succeed. But that is life. Thank you for joining me on this wonderful podcast. You may be wondering, that's an odd name, Boiler Wild. Wild actually stands for something. I came up with it as I was walking around my block.
Eric Johnson (00:28)
Rucking, if you don't know what rucking is, it's walking around and having weight, in my case forty-five pounds, in a backpack. Good core workout, good leg workout. But anyways, I was rucking around trying to come up with a podcast name over a year ago and I came up with Boiler Wild. I wanted something a little off the wall, a little wild, but wild actually stands for something. Stands for work hard, invest in yourself, lead others, and develop yourself into a person of excellence.
Eric Johnson (00:56)
The boiler industry needs leaders, has a lots of great people in it, but more leaders are always needed. More education is always needed. And listening to this podcast, you can become more educated, learn from other people, and be able to lead others eventually. In whatever job role you do, you don't have to be
Eric Johnson (01:20)
in a leadership role in order to lead others. You can lead others being an installer. You can lead others being a technician. You can lead others in how you show up every single day. Do you show up with a positive can do work attitude? Or do you show up being negative Nancy and wanting to put others down and thinking that your boss is out to get you and that the world hates you.
Eric Johnson (01:43)
So today I'm going to talk about a very, very simple idea, concept, topic, but it's one of those topics that lots of people know about lots of people have heard about But if you don't talk about it, if you don't learn about it, how do you know?
Eric Johnson (02:00)
You're not born with this knowledge, but a person that's experienced will know what I'm talking about here, but I am trying to educate everybody. And sometimes you gotta talk about the the little stuff in order for the people to be educated. So you may have heard the topic from the title, but we're gonna talk about triple duty valves.
Eric Johnson (02:23)
And if you know about triple duty valves, this will be a refresher for you. If you don't know what a triple duty valve, well, I have the podcast for you. And I never thought in my life that I'd be recording a podcast about triple duty valves, but here we are. The world is full of surprises. What is a triple duty valve? For so, first of all, we are looking at a typically hydronic system, so hot water system, hot water boilers.
Eric Johnson (02:51)
And a triple duty valve is gonna have to deal with pumps on a steam system. I'm not saying that you won't find a triple duty valve, but they are more rare. Off the top of my head, I can't really think of why you would have a triple duty valve. And I'm only thinking about feed water pumps in a steam system. I'm sure there's probably some triple duty valves somewhere for some application for some steam system.
Eric Johnson (03:18)
But I am talking about a hydronic system, hot water boilers, hot water loop. Water does not move by itself in the pipe. that's a common misconception when people start out in the hydronic boiler market and industry is that the water will move by itself. Water will move by itself with gravity's help and then stop moving. We need a pump to create a differential pressure in order to push
Eric Johnson (03:43)
the water through the pipe. And that is different than steam. Steam is a gas and will move by itself because the gas will expand to the area that it is allowed, which is traveling down the pipe. So anyways, triple duty valve. That is the name of a valve. And luckily in the boiler industry, we are gifted with a naming system that basically puts the name of the part
Eric Johnson (04:10)
In what it does. A triple-duty valve has three functions. Triple, three functions. I know it's wild. I'm I'm glad I'm in the boiler industry because I'm not smart enough to be in an industry that has fancy names for stuff that has nothing to do with what it does. But luckily, somebody was thinking of someone like me when they were naming all this stuff. So a triple-duty valve has three functions in a hydronic system. First of all, let me orient ourselves.
Eric Johnson (04:39)
We are going to be by the pumps. A triple duty valve is going to be on the discharge side of a pump. So you'll have circulation pumps and you will either have pumps depending on your system layout and how it's piped on your hydronic system. You'll have main circulation pumps, which are going to be a little bit larger, depending on the size of the system, but they're going to be a little bit larger. Versus if you have a primary secondary system, you'll have
Eric Johnson (05:08)
boiler pumps
Eric Johnson (05:09)
And you'll have a boiler with a pump next to it, and the pump only pumps water through the boiler. there's no right or wrong way, but it depends on how your system is piped. Is it primary variable or primary secondary? But you will always have pumps in a hot water system. But typically on the main circulation pumps, you will have a triple-duty valve.
Eric Johnson (05:36)
Sometimes you'll have them on the boiler pumps, sometimes not. It all depends on the size of the piping, the size of the pumps, how it's sized, and how much the contractor wants to pay and if they're doing things correctly. But typically you're gonna have them on the main circulation pumps. And if somebody asks you to install triple-duty valve or to look at a triple-duty valve,
Eric Johnson (06:03)
You're always going to be looking at within the first five to eight feet of the discharge side of a pump on a hot water system. So the discharge side of a pump is going to be the outlet. It is going to be pushing water away from the pump, whereas the suction side of the pump is going to be the inlet, and we're sucking water into the inlet of the impeller and then pushing out the discharge of the pump.
Eric Johnson (06:30)
We are going to be pushing out of the discharge of the pump into typically a triple-duty valve. A triple-duty valve has three functions. It is a spring-loaded check valve, it is a balancing valve or a throttling valve, and it is a shutoff or isolation valve. So once again, check valve, balancing valve, isolation valve. What are those three functions?
Eric Johnson (06:59)
The first function is a check valve. A check valve allows flow through the valve in one direction. If you install your triple-duty valve in the correct orientation, it is going to be allowing flow through the valve one way to the other. So in this case, let's just think about something left to right. The flow will go left to right through the valve,
Eric Johnson (07:23)
If for some reason the flow were to reverse, and I'll tell you why it would reverse, but if for some reason the flow would try to reverse and the flow tries to go right to left, the valve would close because the check valve would close and it would stop the flow. So why would flow reverse in a hydronic system?
Eric Johnson (07:44)
so a hydronic system will typically have more pumps than is necessary and the pumps will be spare pumps. If you only install one main circulation pump and that circulation pump has an issue, now you don't have any heat in your building because you can't move your water, even if your boilers are doing great. So you'll typically install.
Eric Johnson (08:07)
If you have one pump that is needed, if the engineer says, All right, we have one pump that is needed, you will typically install a second pump right next to it. And this is called parallel pumping or parallel piping. You have two kinds of pumping. You either have parallel pumping or you have series pumping. And in a hot water system, I've never seen it for a boiler application, but I'm
Eric Johnson (08:34)
Sure, it's out there. I don't want to ever say never, but series pumping is would be a pump connected in series end over end. So you would have suction, discharge, and then the discharge of the first pump would be going right into the suction of the second pump, and that will change the characteristics of the water. I don't want to get into that.
Eric Johnson (08:58)
But it will change the characteristics of the water different versus parallel pumping, where you have the pumps sitting next to each other, and they're not always next to each other, but typically they are sitting next to each other. And the inlet to the pumps, it splits off in parallel. so think about if you were to have a divided highway.
Eric Johnson (09:21)
And you were driving down it, you could either go on one side of the highway or on the other side of the highway, but you're still going the same direction. That is going to be parallel pumping. The water can come in and either go into pump one or pump two. And then when it goes into the suction and then out the discharge of pump one, it can go out into the system. Or the water can come in, depending on which pumps are running, it can come into pump two.
Eric Johnson (09:49)
into the suction, go out the discharge, and then out to the system. It is parallel pumping. And that will change how the water moves different than series pumping. I can't off the top of my head remember seeing series pumping in a hydronic hot water system, but I'm sure it exists. It will always almost always be parallel pumping.
Eric Johnson (10:14)
So, why do we need a triple-duty valve which has a check valve in it? So, if you can think about it and if you're having a hard time thinking about it, you can draw it out, or you can Google like parallel pumping or a pump diagram, pump pump drawing. But if pump one is running and pump two is off, so pump two is not creating a differential pressure, impellers just sitting there, and I said that that they would split so the
Eric Johnson (10:43)
Discharges of both pumps eventually would connect to each other and the suctions eventually connect to each other. And if you don't have a check valve, what can happen is you pump in a circle. So pump one would be on, it would be pulling in water, and then it would be discharging water. And instead of the water getting forced out into the system piping, it would take the path of least resistance and it could just loop back.
Eric Johnson (11:11)
backwards through pump two and go into the discharge and out the suction of pump two and then spin around and then come back through the suction side of pump one. So you'd be pumping in a circle and pump two you would see that the impeller is moving, that the motor is moving, and you could stop it with your finger, but the pump is not going to be powered at that time. That's why you could stop it. Don't stick your finger in rotating parts. I know that
Eric Johnson (11:41)
shouldn't have to be said, but the the pump two would not be powered in this case, but it would be rotating because pump one would be pumping in a circle and you're going to have complaints about low flow in your system. if you have a triple-duty valve installed, the check valve will close when pump one is on and pump two is off.
Eric Johnson (12:04)
So pump one is on and it is forcing water out of the discharge out into the system, and water will naturally put pressure on the top of the triple-duty valve, which will close the check valve and it will seal water from entering back through the triple-duty valve into the discharge side of pump two out the suction and pumping in a circle. You will see this in feed water piping and feed water pumping on steam boilers.
Eric Johnson (12:34)
Although you won't have a triple-duty valve, you'll have a check valve. That is why you need a check valve on the outlet of pumps that are all manifolded together on our steam system for the feed water pumps. When you manifold all the pumps together and all the discharges connect, you need a check valve. Otherwise, the pumps will pump in a circle and you will have issues with feed water volume. If if you didn't already know that, now you know.
Eric Johnson (13:03)
So that is why you have a check valve and a triple-duty valve. The second thing is the balancing valve. So there's what we call we have a pump curve. If you don't know what a pump curve is, I'm gonna briefly explain it, but it's gonna take more than one episode, and I don't think anybody's explained a pump curve on an audio only podcast.
Eric Johnson (13:30)
I don't think I'd be very good at it, but a pump curve is essentially the performance variability of a pump. And it tells you the manufacturer draws out all this data and it tells you how the pump can run, how many gallons per minute it can run pushing against the amount of back pressure. And engineers will use pump curves to size pumps.
Eric Johnson (13:58)
To size the impeller in a pump. The impeller is the spinny thing inside the pump housing that actually contacts the water and pushes the water around. And using different size impellers with different size and models of pumps, engineers will look at the pump curves and determine this is the pump I need versus that pump based on the engineering data around it.
Eric Johnson (14:25)
That's essentially what pump curve is simply. It is the performance data of the pump. It will always follow the curve. There's a curve in the performance data. The pump will always run along that curve or operate along that curve. in a perfect world, you would not need a balancing valve. However, not all pumps are.
Eric Johnson (14:53)
Perfectly sized for the system. And there are steps along pump sizing, if that makes sense, just like a boiler, you will have a 500 horsepower boiler and a 600 horsepower boiler. They don't make 505 horsepower boiler, 510 horsepower boiler. So if an engineer comes up with a a calculation says, Hey, we need 560 horsepower of a boiler.
Eric Johnson (15:19)
They're not going to order a 560 horsepower boiler. They're going to order a 600 horsepower boiler. Same thing with pumps. There's steps and graduations to the pumps. And there's all kinds of other variables, but we have to match the flow and match the pump curve and make sure that the pump is running in the most efficient manner, which is going to be the center of the pump curve, which is going to be the most efficient way to run.
Eric Johnson (15:49)
means you need a balancing valve and the balancing valve will push back on the pump, which seems counterintuitive, but it will push back on the pump and allow the pump to operate better. And adding that resistance actually will make the pump run more towards the center of the curve if that is needed. And
Eric Johnson (16:18)
There's a lot of variability in that, but that's as I think as good as I can explain that. But when you are balancing a system and trying to make sure that the pumps are running correctly, you're going to be turning in or closing this balancing valve, which is going to be throttling the flow through these triple-duty valve, and you will be measuring the differential pressure drop across the triple-duty valve.
Eric Johnson (16:45)
You'll look at the manufacturer's instructions and engineering data, and you will understand how much flow is actually going through the valve. And you will set the triple-duty valve at a certain setting. Typically, they will have a little chart on the stem or next to the stem, and it'll show you like zero to 100% open. You'll be setting the triple-duty valve to maybe like 20% closed.
Eric Johnson (17:12)
And that is going to be a certain amount of GPM flow through the triple duty valve, and that is all going to be based on the performance that you are looking for out of the pump. That is what the balancing valve or the throttling function of the triple duty valve is. It is all about pump performance. And once you set that function, so if we set it at 20% closed.
Eric Johnson (17:39)
It is going to stay there unless we change the pump or need some other change or rebalance the system. There's no need to change that. The third is pretty self-explanatory, is the shutoff isolation function of the triple-duty valve. And that function is going to be to isolate and to close the full valve and to hold it closed. So while the check valve would hold closed against.
Eric Johnson (18:08)
Pressure, it is not gonna be a hundred percent seal off.
Eric Johnson (18:12)
On the outlet of the valve, the positive shutoff isolation function of the valve, you'll run the stem in all the way and it will hold the valve closed. And now you have the isolation on the outlet of your pump. Typically, people will also install a valve on the discharge side of the triple-duty valve, which will just be a single isolation valve, as sometimes triple-duty valves will need to be changed.
Eric Johnson (18:40)
And sometimes triple duty valves will leak and or not move if they stay in the same spot for a long time. So relying on the shutoff isolation of a triple duty valve function, I would probably not a hundred percent rely on that. And it all depends on your designer, how much room you have in your piping. But typically I would install another isolation valve.
Eric Johnson (19:08)
Before you re-manifold all the piping together and go out to the system. But that I'm sure is a design call and engineering call in how the companies want to do it versus what you actually need. And if I wasn't clear, all those three functions are included in one housing. So it is one housing, one valve. You're gonna pick up a triple-duty valve and install it.
Eric Johnson (19:33)
The small ones are going to be threaded, the larger ones obviously gonna be flanged. And instead of installing a check valve and then installing a balancing valve and then installing an isolation valve, they said, hey, we're gonna engineer and put all three functions into one housing so that we we can save on the pipe length and save on the amount of components. Otherwise, you would need way more pipe room and pipe length off the discharge side of the pump.
Eric Johnson (20:02)
in order to fit all three components, the check valve, the balancing valve, and the isolation valve. That would cause a lot of issues when you have not a lot of room on the discharge side of the pump. So we came up with the triple duty valve and all three functions are now in the valve.
Eric Johnson (20:20)
I want to talk more about the balancing part of the valve. As I said, you will want to push back against the pump depending on the pump size. I want to go briefly into two scenarios. If you undersize a pump, you will do less pushing back with the triple-duty valve.
Eric Johnson (20:38)
And if you undersize the pump too much, the typically just the pressure drop across the triple duty valve when it's a hundred percent open will just be enough, or you've undersized the pump so much that it's actually the wrong pump. But if you only have to close a triple duty valve ten percent, that is a pretty good number. And there's no like perfect number for closing a triple duty valve. Like you're not gonna engineer to
Eric Johnson (21:08)
Have it closed at 30%. It's gonna vary just like the pump sizing is gonna vary, and that's why they make it variable so that you can adjust it to what you need. But if you're barely closing the triple duty valve, the pump is closer to the amount of flow that you need. not every triple-duty valve is gonna be more closed. But if you come across a pump when the triple-duty valve, if it's 80% closed.
Eric Johnson (21:36)
That means that that pump is way oversized. And why is this bad? Because the pump is operating correctly and the triple-duty valve is 80% closed. And that would be fine in a perfect world, but we gotta think about what we're paying for. We are paying for electricity, or at least the owner of the pump is paying for electricity to spin an impeller and to push water.
Eric Johnson (22:02)
Against a valve that is 80% closed. So we end up wasting a lot of energy pushing water against a valve that is 80% closed. And essentially, we are moving too much water or attempting to move too much water. So therefore, we need to close the triple-duty valve more in order to balance that out so that we can move the pump
Eric Johnson (22:28)
more towards the center of the pump curve and get it into better performance for the system. The the pump is actually oversized in that situation. And this is bad because while it may work, you end up paying for a lot of energy. So what can you do instead of just cranking down on your triple duty valve, you can either get a different pump or you can trim the impeller. Impellers will come in different sizes. You can buy an impeller that's
Eric Johnson (22:57)
Eight inches or seven and a half inches, and those are just examples. But the diameter of the impeller, a larger diameter is obviously going to move more water, and that will change. And the impeller sizing will be on the pump curve, and they will have different curves for different sizes and impellers. And if you need a smaller pump,
Eric Johnson (23:21)
But want to maintain the same housing, you can actually trim the impeller or have the impeller trimmed or order a new impeller. And now you can reinstall the new impeller that's smaller, and you will have less flow through that pump, which is a lot cheaper than replacing the entire pump, or maybe the pump sizing and housing is the only housing that's correct for that, and you just ordered the wrong impeller, or I know it's unheard of, but the manufacturer installed the wrong impeller.
Eric Johnson (23:51)
And they installed it too big versus what you ordered. So if the impeller is too big, if you're moving too much water, you can trim down the impeller. So now you're gonna be moving less water, which will naturally make you or allow you to open the triple-duty valve more because you're not gonna have to push back on the outlet of the pump more in order to keep the pump in the center of the pump curve. And the center is where the pump is most happy.
Eric Johnson (24:21)
and is most efficient. But we don't want to spend all of our energy trying to push against a triple-duty valve that is 80% closed. Another way you can
Eric Johnson (24:32)
Help with an oversized pump is add a VFD. A VFD allows you to change the speed of the pump. make sure that the motor is rated for VFD if you're doing a retrofit application. A lot of motors are, but a lot of older motors are not rated for VFDs. But make sure the motor has a VFD rating. But
Eric Johnson (24:55)
Allowing the motor to spin at a different RPM by modulating the Hertz frequency is hertz. So typically in the United States, you'll run a motor at 60 Hertz. That is the normal amount that power is fed. Europe is 50 Hertz. So at 60 Hertz, that is how many times the wavelength crosses zero, sixty times a second.
Eric Johnson (25:24)
If we change the Hertz and we go to 40 hertz, the motor will then spin slower, it'll have less RPMs and therefore will push less water. And now you can open your triple-duty valve more because you don't have to push back on it. And that is what the balancing function can do, and that's why it can help you. But I want you to know you're probably not designing.
Eric Johnson (25:52)
Maybe you are designing, but the typical steps of learning and progression are object identification. You'll be able to point out a triple duty valve and then the service side of it. So maybe the customer says, Hey, this isn't working correctly, or you're working with somebody, maybe you're changing out a pump. Maybe you change out the triple duty valve and you go there to change out a triple duty valve for whatever reason and the old one, and you'll look at it and you'll see.
Eric Johnson (26:20)
On the marking, you'll say, it's eighty percent closed. Well, why is it eighty percent closed? Well, at somebody at some point, they determine that it it needs to be eighty percent closed. I would check that, but with the performance data and with the pump and everything, but when you're installing the new triple duty valve, you can't just leave it a hundred percent open on the balancing stem.
Eric Johnson (26:45)
Otherwise the pump is gonna run all the way to one side of the curve and you're gonna have issues with flow with the pump. It's the pump is not gonna be happy. So you need to put the triple duty valve back to the location that it was originally set at. And if it's like for like, typically you can just make a mark on the old triple duty valve and make sure you mark the new triple duty valve and put the stem and close it just enough.
Eric Johnson (27:13)
that it is the same as the other triple duty valve and now you'll be happy, good to go. And you don't really have to know the why behind why it's there and reading a pump curve and reading the differential pressure across the triple duty valve. But that would be an important part of the service side. Also, if you do use the isolation function of a triple duty valve, you're gonna want to know or mark where the balancing function is because you're gonna be cranking that valve all the way closed.
Eric Johnson (27:41)
And then when you go to open it, you're not going to want to open the triple duty valve a hundred percent if it was set at 50% closed. So you're gonna want to know on the marking on the graduation, the zero to 100% open, it'll have a marking on the stem and next to the stem of where the valve is set. You're gonna want to make sure that that triple duty valve remains at the 50% mark if it was set at 50% before you closed it.
Eric Johnson (28:10)
But now you know why a triple duty valve has those three functions. Now you know where to find it. If somebody says, hey, go change this triple duty valve, you're gonna go find your system pumps, your circulation pumps, You're gonna know that the triple duty valve has three functions. It's got a check valve function to prevent reverse feed through the pump, which will happen when you have pumps in parallel.
Eric Johnson (28:36)
And I know you're smart listening to this, but if you only had one pump, you wouldn't need a triple duty valve per se for the check valve function because the flow would never reverse because you would only have one pump, but you could have a need for a balancing valve. So I'm not going say you won't have a triple duty valve when you only have one pump, but the check valve function is kind of redundant and not necessary.
Eric Johnson (29:00)
I'm sure it will stop flow back through the pump though if the system is off and if water goes the opposite way. So if you have the money for it and room for it, I would install it. But it's not 100% necessary to have that check valve. But that's that's the check valve function. The second function is the balancing valve. Once again, we use the balancing valve to keep the pump happy. You need to learn more about pump curves on why that balancing valve is needed.
Eric Johnson (29:28)
But essentially it makes the pump happy and gives the pump optimum performance. If you don't have that balancing valve, people try to balance with isolation valves, with butterfly valves, and that will wear out the isolation valve, and the isolation valve will move, and it is not an exact science of where that isolation valve sits. So then you start guessing that the isolation valve, it's closed two turns, and you're guessing, and there's really no way.
Eric Johnson (29:56)
across the normal isolation valve to measure the differential pressure drop because you are using an isolation valve for a balancing function and when you actually need to close that isolation valve and make sure that it is leak tight because you are changing the pump that isolation valve will probably leak. So don't use isolation valves for balancing. That is why they make balancing functions or balancing valves and not isolation valves
Eric Johnson (30:26)
Only for balancing. The third function is isolation. If you need to change out the pump, remove the strainer, clean the strainer, check the impeller, do all that stuff. You can close your triple-duty valve. It is probably good practice to move your triple-duty valves as an exercise of valve to make sure that stem moves. I have cracked off a stem from trying to close a triple-duty valve when there was no other way to isolate a pump.
Eric Johnson (30:54)
And that was a issue. The system was pretty large, but I cracked off the stem. I did everything I could to try to work the stem. But that triple duty valve was a hundred percent frozen in place because it had never in its thirty to forty year life span it didn't seem to have ever been moved. And I was not gonna be the one that was gonna make it move. So I hope you learned something today. I know it's low level stuff, but
Eric Johnson (31:22)
No humans born knowing what a triple duty valve is. So if you learn something, please tell me or rate the podcast. That would help me rate it five stars. Or email me, Eric.johnson at boilearn.com or DM me on LinkedIn. Let me know if you learned something or if you have any good triple-duty valve stories, or if you want to be a guest on the podcast. Always looking for new knowledgeable guests who have stories and experience that other people can learn from.
Eric Johnson (31:52)
So I thank you for listening and stay wild.
