Does a Steam Boiler's Equalizer Actually Equalize Anything? (2023)


The residential steam community has been told and generally believes that the "equalizer" serves to equalize pressure between the header and the connection to the wet return in order to prevent the water level at the far end of the wet return from rising too high.

But does it do this? Let's find out in this video!

Here is a link to the drawings and forum post I referred to:


All right welcome to my basement and my boiler, uh, this is gonna be a video where I try to demonstrate the idea that The Equalizer doesn't do anything to equalize any pressure anywhere and uh, I'm gonna put an asterisk on there and I'll say, not counting freak occurrences where your wet return suddenly gets a quarter sized hole in it and uh, all the water leaks out or whatever your boiler is going to dry fire.

If that happens.

So it's just bear.

We never heard about this before today set this aside.

We've been told that the equalizer balances the pressure between the header and the wet return or the entry point, you know into the wet return where the Hartford Loop is right, there's, The, Equalizer running down right here.

So it it's supposed to equalize that supposed to be some pressure difference, or something that it equalizes, which then causes or prevents rather prevents the the water level at the far end of the main okay at the at the drip that goes down to the wet return from the end of the main supposed to prevent that water level from rising too much.

Right and shooting out of your main vent, which, you know if you're it, you know, if if that was a concern, you know, if that was a thing that could happen, it would be a concern because you know, 3 PSI is like nearly 60 inches of, uh, or no nearly 90 inches of, you know, water column.

And yeah, that that if there was a differential like that that would cause the water to rise, uh up to your end of your main.

And you know, shoot out of your main event or or even go further, go up to your first floor, radiators, let's, say and uh, so that's.

What the equalizer supposedly does now I've made the claim that when I look at this I can't figure out what it would equalize right and I've I've drawn this picture everyone's seen it.

But so you've got some pressure here on my pictures.

I said, 5, PSI.

But for the sake of whatever let's say, it's, three, PSI, you got three PSI here.

We know we have a three PSI in the in the steam chamber of the boiler.

As you go lower in the boiler it's going to slightly increase because of the the additional weight of the water, that's that's, uh, that's, there we'll increase the pressure a little bit granted, right? But uh in the header, it should be 3 PSI, um, The Equalizer, of course, is here so it's, it's, pushing 3 PSI down here as well and that's where we've been told that somehow it keeps somehow the pressure knows only to push this way toward the boiler.

Somehow, the pressure, doesn't know to push this way down the Hartford Loop into the wet return, thereby, you know raising the water level in the in the wet return that's.

The part that always confused me so I'm gonna do a demonstration.

What you can see here is I, added a valve to my equalizer.

So equalizer comes down now there's a valve there I'm going to be able to turn that off and it'll be just like I have no equalizer at all right agreed.

And at that point, we'll know, whatever pressure is in the boiler is is is getting presented to the wet return from here and uh, you know, of course, also getting sent up to the main now it's.

My proposal it's.

My it's, my thinking that the equalizer is not what prevents the water from rising over there.

At the far end of the main it's, actually the main itself.

If you think about it, if I'm running 3 PSI in my boiler I'm going to have 3 PSI going going across my main okay, can we agree to set aside velocity drag of the of the pipe or whatever? This is not, you know, a 100 PSI steam or something.

This is It's traveling okay, but I don't think it's getting like skidded to a stop by the walls of the pipe here.

And when you get to a uh, a radiator take off like this, one I got another one over here right there.

Each of those you'd expect to be a little pressure drop at each one of those because the steam is Flowing out, you know to the radiators where it's condensing so that we do.

We do expect the pressure to to reduce.

And when the in the main wraps around my basement, you can see it there, insulated, The, Man, Comes, Around.

And by the time it gets here.

These are the this is.

These are the last two takeoffs right here by the time it gets here.

It should be a little less than whatever's in the boiler right now.

I've never measured it.

But we know it's less than three PSI or whatever is in the boiler, uh, right? We all can agree it's going to be somewhat less that's.

What makes the water rise here and uh, but it's going to be a question of how much and like I said in my in my proposal, my thinking is here's your little bit less than 3 PSI it's pushing down it's pushing down.

Right here approximately here is my boiler water line.

And if there's a differ, if there's a differential there, we'd expect to see this come up now I can tell you in my operation here it doesn't.

It never appears in the glass unless I'm goofing around with my boiler in some weird way, which I'll show you later, probably, but in normal operation, the level is never visible here in this glass, I've often wanted to add another glass below it.

So I could see the actual water level at all times over here.

That's kind of cool, I think.

But uh, the idea is when I turn off this when I separate off The Equalizer, according to the theory that the equalizer is preventing the water from getting pushed backwards out of the boiler.

If I turn this off I would think people would expect that that is going to rise here because the equalizer is no longer doing its job right now, according to my drawings that wouldn't happen, but I can't, get anyone to say, yes, your drawings are right with very few exceptions.

Everyone says, oh, they won't say, my drawings are wrong.

Either they're just not commenting on my drawings, which is fine, whatever they're just drawings, but this will be a real experiment.

So that's the intro.

So my boiler just kicked on I've got a I got a long call for heat set up I've turned off a bunch of my radiators to and I've.

Also I've also turned off.

My main vent for experimentation purposes.

I have this valve before my main vent.

And so that that should let some pressure build in my system, which normally there's, hardly any pressure there's like less than one inch of water column in this thing, usually.

But with all those radiators turned off, and my main vent turned off I should be able to build up some pressure, and we should and I, oh, yeah and I raised my pressure troll up to about 3 PSI cut off, um, or excuse me cut in is three.

So the cut off the cutout will be like what two is that right? It's differential.

Yeah, subtractive.

Does it say that? Yeah, wait no additive.

So it's going to be four and three, yeah, four cut out and three cut in it should be so we'll.

See if we get it that high I, don't know, if it'll get that high or not, but I have a an accurate low pressure gauge here.

I wish I had a Magna helic here that had a big enough range, but I'm using my only large range magnet helic over here.

So we can see what we get over here.

This is a 50 inches of water column meter 0 to 50.

Of course, we don't really, we don't really need this meter this gauge over on this side because we'll see the water level come up, right, that's, what that's what we're going to find out so, uh, that was the long intro.

Sorry about that rambling and stuff.

But I hope, you get the idea of what I'm going to try to do the boiler is heating up right now and uh, I'll be back when we're steaming and uh, and it will do some experiments Okay.

So we've been running for a while and I've got, uh, I did open up.

My main vent because I got I kind of had to get steam in the whole main to get everything nice and hot and get get some of my radiators starting to warm up and I am starting to build pressure.

So, um, normally I wouldn't, see this pressure until I, don't know in a really long set call for heat on a setback, but um I've been the boiler's been firing for about a half hour.

And you can see the pressure's starting to build.

And this is good it's kind of building a little slowly here, which is, which is good I've, got about half.

My radiators turned off.

So uh, overall that's, a good size.

The way my system runs I think, but uh, setting that aside so we're at um, what 0.6 getting close to 0.7 PSI on on the boiler side of things.

And over here, at the far end of the main we are at uh, okay.

So 15 so a little more than half of a PSI over here.

That's great.

We can see the condensate running returning back to the um to the wet return from the far end of the main.

This is just a regular.

Parallel main one pipe situation, no sign of the water level coming up, right? So, you know, I, again, I suspect it's around here, but I can't verify that except to know that it's below here somewhere so that's, fine, I mean, it can't be much below here because that's where the water level of the boiler is right now about 31 inches off the floor so everything's running.

This is slowly climbing.

So let's, let's, try the first experiment so here's, the here's, my new valve on my equalizer, um, let me turn on my light here for this I'm going to try and do this sorry, it's going to be shaky I'm going to zoom in on my Magna helic over there and you'll be able to see any water that that goes up in the sight glass over there.

So here it is I'm going to turn this off.

So there it's off now did anything change over there according to what we you know what the general feelings are out there in the industry by closing off The Equalizer, right? It should like allow more water to be pushed out the back end of the boiler into the wet, return and force the water level higher over there at the far end, right that's.

What we've been told in, um in the Lost Art, steam, Heating and um, we should be able to see that now we'll keep doing it as the pressure builds.

You can see we're up here almost to 1 psi.

And the Magna helic is reflecting that over there as well and that's with the equalizer turned off, not existent.

So why how is that possible again, I'm going to I'm going to say it again, while we wait for the pressure to build and do some more experiments.

The Equalizer is actually not this thing.

The Equalizer is actually the main because we're sitting here at one PSI there's, one PSI in the boiler there's, approximately one PSI at the entry of the wet return back to the boiler there's.

One PSI in the header there's, one PSI in this part of the main there's, one PSI, all the way to that first run out and actually I've got that radiator turned off.

So there's, one, PSI, farther, uh, you know, farther around until we actually get to some radiators that are working.

And those are condensing steam.

We know, we're condensing steam.

Because even though my system is small it's still producing, you know, it's full it's full BTU rating of steam and it's sitting about even right now.

So right now, the radiators are filling up with steam is what's happening, but the pressure it will drop a little bit at each radiator.

You know, that's working.

And by the time it gets here, it'll be something.

It should be something less than what we see over at the um at the boiler.

So at this moment, we're we're about one PSI, right now that would be what 27 inches of water and that's right about where we're at over here.

So we would we might expect it to be a little higher than that.

Here, it's, not showing a little higher it's showing just a shy of one.

Now, this gauge I don't, trust nearly as much as the Magna Helix.

So I, don't know what to tell you there I gotta I can run this again, I'm going to get some more of those 0 to 50 Magna Helix and put them around in some places.

You can get them, pretty cheap on eBay.

You can find them for like, 20 bucks, plus shipping.

Sometimes it's, pretty good.



We see that even with the equalizer turned off.

The pressure is is still equal at the far end of the main right up there, we're at uh, 27 28 inches of water.

And here look we're, even a little lower it's.

Interesting quite one PSI here and that's what the equalizer turned off.

So let's, the camera here on the Magna helic and I'm going to turn the equalizer on and we'll see if we see any chains Okay.

So there it is on it's on it's on it's on I didn't, see it even move.

It didn't even budge.

Okay, I.


It off.

I don't see a flicker currently off it's off it's off turn it back on right now.

It doesn't seem to move.


We are getting some we're getting actually a little bit of a drop in the pressure of my system overall right now, which if you've monitored your systems carefully as they're heating up, you'll know, you do know that they do kind of go up and down, depending on what's going on like with the movement of the steam to different parts of the radiator, I, don't know, exactly.

But you you see the the uh, the pressure kind of kind of move up and down, but generally speaking we're, sitting we're, sitting pretty steady I'm, looking forward to when um, some of the radiators start get completely full.

And when they're when their vents close, then we should see, we should see it rise, uh to the cutout and I did lower this a little bit because I didn't want it cutting out at four so I lowered it to this a little over two so two and a quarter, two and a half something like that.

So it it should cut out somewhere between three and four so that's, the first experiment, no no result.

No, no change in anything I can turn it on and off on and off.

No it's on right now.

No, uh, I.

Turn it off.

No water shows up and the Magna helic doesn't budge.

Now, my cycle guard just kicked on so that's, a good time for me to stop this section of the video and um I'll be back when the pressure, uh starts to climb let's say, you know to 2, PSI, we'll, see if we notice anything different all right now, we're getting somewhere, uh, I, closed off another radiator to uh to make some pressure build a little faster.

So here we are one and a half PSI at the boiler The Equalizer is open and uh over there across the room we're at it's reading about 40 inches of water column.

So, uh, yeah, I think, that's a that's, roughly one and a half up I got to get my calculator out 27 times one and a half would be.

Uh, yeah, that'd be about 40.

So that's, good so they're about equivalent, which is good, um, we're climbing now we're, getting some pressure some noise over across the room, I'm, not sure what that is something's starting to see some pressure that it hasn't seen very much my system.

My system's never maybe been this High since I installed it.

But anyway, let's, um, let's, try to uh, close the, um The.

Equalizer, see what happens before we top out the Magna helic over there? Okay, I close.

It I don't.

See it move it's right about at 47 right now.

I open.

It I don't, see anything, there's, no sign of water over there.

I close.


Nothing happens.

I open.


Nothing happens we're up to we're up to two now.

It's, closed, it's open we're about at 50.

inches of water over there.

Now, surely with the with this closed The Equalizer closed, um, we don't see any Water Rising in the sight glass.

How could that be right? The? Equalizer is supposed to be equalizing fact, this out the equalizer is supposed to be somehow equalizing the pressure here in the near boiler area to keep to prevent the pressure of the boiler now, sitting at uh, two and a quarter PSI to keep that pressure from somehow to keep it from pushing on the on the return, Water right, that's, what's supposed to be happening.

But even without the equalizer there's, no appearance of water over there that that water level is not Rising.

And the Magna helic is now pretty much maxed out.

But all the way up to that point it was, it was matching the boiler pressure with some some variants, but not the kind of variance that obviously not the kind of variants that would make the water rise.

So so what's, the explanation I said it before and I'll I'll say it, again, two and a half right, there's, two and a half here, there's, two and a half here, there's, two and a half here, it's hitting the valve right, there's, two and a half here, roughly okay, there's a little bit of height of water here, right? But basically two and a half PSI is here you get to hear it's going to be it's about at the water level like, you know, right here so that's going to be about this that same two and a half PSI, hmm, my, um, my Union's dripping, a little bit.

So uh, I have to fix that, but uh, two and a half PSI, two and a half right and that's that's without The Equalizer, right? But if I open the equalizer, nothing changes they're, still two and a half here, there's, two and a half here, two and a half comes down here and pushes here to meet equally with the two and a half that's coming out of the boiler it's, all it's already, equal The.

Equalizer doesn't, do anything to equalize the pressure, two and a half two and a half now we're up to three three, three, three, three, well, okay, well, what what keeps that water from rising over there then it's, not the equalizer.

We know this it's.

The main the main has three three, three, three, three, three, three, a little less than three a little bit less than three a little bit less than three a little bit less than three very little bit less than three.

We know because we saw the Magna helic was was matching the other, uh meter so that.

So the pressure drop to the radiators is not that much we saw it.

So The Equalizer is here here's.

The equalizer it's pushing down.

If this was one PSI, if this was 2 PSI, and the boiler was at three, we would see this come up 27 inches.

Right? One, PSI difference would be 27 inches of water.

We're, not seeing we're, not even seeing two or three inches.

Now, here's.

The cool part right, put my SEC, my cycle guard, doesn't, kick in right now, because you want to see the water rise here's, how we make the water rise here's a valve.

This is equivalent to like a king valve right? I have two valves.

I already have this one off.

This is my Riser out of my boiler.

Of course, I can turn this off and I hope not burn myself while I'm messing around with this, but I'm going to keep the camera over here on the wet return.

Watch as I start to close the valve that provides steam to the main right, which is what I'm calling the equalizer.

Now, the main is The, Equalizer, I start to close.

It I close.

It I close.


Look at there, I've it's, I've, got it cracked right now.

I got it right here.

And look, you can see weird stuff is happening.

Weird stuff is happening.

I, don't know, if it's a pressure situation that's causing this.

The pressure is is way up now past this gauge anyway, I expect the pressure troll will kick in pretty soon, but I'm I've got it I've got it in equilibrium where I've made a differential now it's raised to the height of that water at my at my wet return side over there at the end of main drip or end of main drop, you'd call it it's raised at like six or eight inches.

So that's, not very much that's like a third of a PSI.

If I close it further I can maybe go higher.

Look there.

It goes it's going higher now it's somewhere up Beyond up there, it's, right at the top of the glass, it's like equilibrium it's, right? There saw it.

We saw it reappear there.

It is see that it's right there if I close this valve I know from experience this valve.

Okay, not the useless equalizer valve that doesn't do anything if I close this valve, of course, we're going to see a big difference in pressure now, I don't want to do that because I did it once.

And it immediately shot Water up to my main vent, no question.

But here I'll do it again, I'm, slowly closing the valve causing this pressure differential, the boiler now is higher pressure than the main and it's causing the water level to rise.

Rise rise rise right? That's the action that I believe everybody thinks The Equalizer is preventing, but it has nothing to do with it.

Folks, nothing I can close this thing all day long.

We don't see anything over there.

Not a thing right? Tell me, uh, tell me how else I can prove it to you I.

Think this matches what my drawing showed, um, thanks for everybody who has, uh, given me feedback on that thread I, really appreciate it.

All the opinions I like to hear them all I don't care if they agree with me or not, but uh, I hope that you can see from my experiment here, The Equalizer, just doesn't do anything to affect the pressure of the system, not a damn thing.

I wish, my pressure, troll would kick in I wonder.

What my pressure is at right now.

Well, I think it's not at 15 yet, oh there.

It went all right that was my pressure.

Troll see we're up, I, don't know, we're up it, four or five PSI.

You can't trust, these damn things.

But uh, yeah, the pressure troll kicked in because it was not my cycle guard this time.

So that's, good that's.

The first that's, the first time I think my pressure troll has turned off my system and I, don't know how long anyway, that's it.

Thanks for watching, um I think I think I showed what I wanted to show with that.

Uh, equalizer valve, uh, I, make a new thread with this video on it.

Probably that old thread has gotten so polluted with all kinds of different stuff in it it's hard to follow along with, but uh, let me know in the new thread what you want.

Uh, what you want me to do to to try and prove it to you that the The Equalizer doesn't, equalize.

Okay, catch you later.


What does an equalizer do on a steam boiler? ›

The end of the header drops vertically below the boiler's water line and connects into the bottom of the boiler. We call this pipe the “equalizer” because it balances the pressure between the boiler's steam outlet and condensate-return inlet.

What does the Hartford Loop do? ›

The Hartford loop is needed to prevent steam pressure in the condensate return line from forcing the liquid condensate (water) out of the boiler and back into the return piping system - something that could be a serious problem resulting in boiler water loss and boiler damage or destruction.

What is the maximum pressure for steam in residential boilers? ›

Steam Boilers must have at least one safety valve with a set pressure not to exceed 15 psi. Hot water boilers must have at least one safety relief valve with a set pressure at or below the maximum allowable working pressure (MAWP) marked on the boiler.

What is the main function of equalizer? ›

The equalizer function adjusts the sound quality of songs. The equalizer function uses the “xLOUD” technology developed by Sony Corporation. This technology optimizes the audio playback level.

What is the purpose of an equalizer? ›

A recording of music or spoken word can pick up a variety of tones, not all of them pleasant. A graphic equalizer (EQ) offers a simple solution: boost or cut (make louder or softer) a specific range of frequencies to improve sound quality.

What is the difference between the Gifford loop and the Hartford loop? ›

The difference between the Gifford Loop and Hartford Loop is where condensate water re-enters the system. With the Hartford Loop, it is re-introduced 2 inches below the boilers minimum water line. The Gifford Loop introduces it at one-half inch above the water line.

What is the proper height of the Hartford Loop? ›

A proper Hartford Loop is taken off the equalizing line of the boiler piping with its center 2″ below the normal water line. The shortest possible nipple and an immediate elbow turn the loop down to meet the wet return, forming a water seal.

What is a steam loop used for? ›

noun. : an arrangement of pipes by which water of condensation can be returned to the boiler without a pump or injector as a result of condensation of boiler steam in a loop of two vertical pipes connected by a horizontal one.

Can a steam boiler build too much pressure? ›

How to reduce pressure from your boiler
  1. Open the filter valve. Many (but not all) central heating systems have a filter, which water continually cycles through to remove impurities. ...
  2. Use a drain-off valve. ...
  3. Bleed a radiator. ...
  4. Undo a radiator nut.

Is 25 psi too high for boiler? ›

Most boilers are safe up to around 30 psi, at which point seals can begin to fail. Modern boilers aren't nearly as dangerous as early steam engines , but you can still damage them and require costly repairs. Provided your boiler stays in the 12-30 psi range, you're in no real danger.

What is ideal steam pressure? ›

The pressure of steam selected should be corresponding to the temperature of steam. For example if the final temperature required in a process is 110 degree C., then the ideal temperature value for steam is 145 Deg. C. and corresponding pressure is bar (a) or 3.16 bar(g).

What is the function of equalizer filter? ›

Filters and Equalizers process sound in the frequency domain, and as a result they are used to modify the spectrum of the sound, that is, its frequency content, and hence its timbre.

What does the equalizer pipe do? ›

An external equalizer is a piped connection, specifically sized to maintain equal water levels between multiple cells or multiple units for an open cooling tower system. Equalizers must be used when two or more cooling towers are piped with a common header.

What is the purpose of an equalizer pipe in a steam boiler quizlet? ›

-An equalizer connects the lower outlet to the steam outlet.

How do I increase steam flow in my boiler? ›

15 Ways To Increase Boiler Efficiency
  1. Increase Boiler Efficiency: Lower the Stack Temperature. ...
  2. Install an Economizer. ...
  3. Tune the Burner Regularly. ...
  4. Install a Variable Frequency Drive. ...
  5. Insulate Your Valves. ...
  6. Clean the Fireside. ...
  7. Preheat Combustion Air. ...
  8. Clean the Water Side.
Apr 19, 2022

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