Equalizer disabled experiment video

JohnNY

Someone watch and tell me what happens in this video in 30 words or less.

ethicalpaul

Regardless of if my equalizer valve was open or closed, and regardless of pressure from 0 to 5psi, the pressure in the steam chamber always matched the pressure at the end of the main, resulting in no change to water level in the drip to the wet return

Someone correct me if I mis-stated that.

Matt_67

What about a system with not only heating but also steam driven engines or turbines. Where some condensate returns but some is wasted.

109A_5

Hello @ethicalpaul,

Yes, I totaly agree that with your system as the working example you will have to artificially induce the situation. I guess it depend on if you want to see it or not (and time and cost issues too). With your system you may have to measure the pressure with the resolution in microns to see it. And I agree that with your system running normally measuring the effect may be impossible. And I agree with systems like yours the equalizer's purpose may be simply limited to a header drip. I believe before it was called an equalizer a similar pipe was called a Bypass pipe.

I think what others are trying to say is with other systems that have additional equipment like bigger boilers, zone valves, various traps, condensation tanks vented the the atmosphere the value of the equalizer may be more than just a header drip. And in the eyes of the boiler's manufacture it is 'best practice' for very low cost.

Instead of calling it an Equalizer should we call it the Queen Latifah pipe ? There is a King valve.

ethicalpaul

Thanks @109A_5 I don't truly care what we decide to call it…lots of things are called by false names. I don't need to see the occurrence with my own eyes on my own boiler. I'm just trying to learn when this imbalance can occur in a system lets say from 100k BTU to 2 million BTU in heating systems, because currently I can't picture when it might occur.

As systems get bigger, all the pipes get bigger to handle the flow of steam, so there must be some other situation that can make it happen because lots of people say it can happen (the rising of water level in the end-of-main drop to the wet return).

Or must there?? Surely if multiple people here have seen this occur, it should be no problem to describe when it occurs, right?

Or maybe it doesn't really occur! Maybe it was just surging that lowered the water level and made water shoot out of the vents. Even I have seen that!

EdTheHeaterMan

https://forum.heatinghelp.com/discussion/comment/1744038#Comment_1744038

Here is how it was explained to me many years ago:

A steam boiler has many uses. One can be process steam. Lets look at this first then we can get back to heating boilers.

Everything is equal here

Then the burner is turned on. The water starts to heat, then boil off the steam.

Then pressure starts to build for the process of baking or something else. Only a few PSI is needed. Lets add a water source and an overflow. The Gas valve fails open, so no electrical current to the valve but it is stuck open. (could have failed mechanically like the church, or a worker could have manually opened it … there were some old valves that you could do that to) So no LWCO is goint to help here because turning off the electric won't stop the fire.

Next thing the water feed can't keep up with the overflow caused by the 5 PSI forcing the water out the overflow that is 10 feet above the boiler. No one took into account that the boiler might ever get to 5 PSI so the overflow was only 10 ft high and water never came out the overflow.

If there was a equalizer and a HL this boiler would never have failed

Now lets look at a heating boiler with radiators

Let's say that two thing happen. The main vent fails open and goes unnoticed for some time. At less than 1/2 PSI it could go unnoticed in a vented crawl space. Then at some later date the gas valve fails open like what happened at the church. The burner will not stop firing. The radiators heat up and keep heating and all the vents close, but the failed main vent allows steam to pour out into the crawl space with enough velocity to cause the pressure drop like shown in this diagram. So steam is moving fast thru the main and the pipe friction loss allows the pressure at the end of main to drop enough to cause the water line in the boiler to be pushed below the safe operating level. As shown here the Equalizer provides a syphon intruption and the pressure of the boiler steam is equal to the pressure of the return pipe and the pressure forcing water up and out of the wet return into the dry return and the lower pressure connection between the dry return and the main. So something needs to go wrong for the piping design to be "needed".

All you need to do is create something where nothing can go wrong then you don't need to prepare for something that might go wrong.

I this a little bit helpful Paul?

ChrisJ

Are Hartford loops used on steam engines, like locomotives, ships like Titanic etc?

I assume no because they have some funky injector….

What about nuclear reactors? Are there Hartford loops on those?

ethicalpaul

No, it's not too helpful Ed…these are pretty convoluted 😅 We are not talking about process steam here I don't think, and is there even a wet return in process steam? (don't even answer, I kind of don't care LOL), and I'm not talking about gas valves being stuck open once in an x year career.

People and I think TLAOST are saying that the equalizer exists because without it, pressure in the boiler (a normally operating boiler!!) will force water out the back, to the wet return, and the water level will rise to the main at the far end of the wet return.

Nothing I have been able to imagine or show in experiment has shown even a hint of this to be true. I'm just about ready to say "it doesn't happen, period" and then we can all stop talking about it, but I hold out the possibility that there is something out there I haven't thought of. If no one can state it, that's OK!

109A_5

Hello @ethicalpaul,

Sure the majority of the folks that have witnesed it may be dead and the boiler's have been replaced with boilers with much smaller water surface area. I wonder about Breweries, I think they run higher pressures.

And mistaken symtoms is certainly posible. However I believe it can happen with the right conditions, which I would say are not the correct conditions that a small residential system should be run with.

EdTheHeaterMan

Then we need to look at the last section only. So we can agree that high pressure moves tp low pressure. Are you asking "How does the pressure at the end of the main get low enough to cause the water in the boiler to get pushed out the return (assuming no equalizer) ?

EdTheHeaterMan

https://forum.heatinghelp.com/discussion/comment/1744027#Comment_1744027

Actually there may be a large difference in pressure between one end of a pipe and the other end of a pipe. Try this experiment. Place a pressure gauge at the water meter in your home with all valvers closed. Then place a pressure gauge at the end of 200 feet of garden hose connected to the outdoor spigot with a full port valve closed. Both gauges will read about the same with maybe a little difference for the hight of the gauge.

Open the valve and watch the pressure at the hose end and the gauge at the water meter. the gauge at the end of the hose will drop much more that the gauge at the meter. That is becausee there is more friction loss at the end of the hose ther there is at the meter. So Chris you need to describe what you mean by "VERY CLOSE". The pressure difference of just 1PSI is going to push the water up the return pipe 28". and that is under normal operating conditions

ethicalpaul

Next thing the water feed can't keep up with the overflow caused by the 5 PSI forcing the water out the overflow that is 10 feet above the boiler. No one took into account that the boiler might ever get to 5 PSI so the overflow was only 10 ft high and water never came out the overflow. 

If there was a equalizer and a HL this boiler would never have failed

I disagree. This would fail. The equalizer doesn't affect pressure away from the boiler as I am pretty sure we have both agreed many times 😁

ethicalpaul

https://forum.heatinghelp.com/discussion/comment/1744068#Comment_1744068

Yes. With or without equalizer how would this happen. I think this is the 10th time I've asked 😂

Let's stick with boilers, not water hoses for the sake of my sanity 😨

EdTheHeaterMan

Then we would need to go to some engineering manuals and look up friction loss based on steam velocity related to a given pipe diameter.

Any fluid including steam will loose some of the energy it has as it moves thru a pipe. The energy I'm speaking of is measured in PSI pressure.

So the last part of the post states that the flame will not stop. So that means that steam pressure will continue to increase until such time that the energy of the flame and energy of the pressure leaving the system is equal. I'm going to give that a number 5 PSI based on the way that the main vent failed. The velocity of the steam moving out the failed main vent is sufficient to cause a loss of pressure energy by 50%. This is my example so I can make the vent fail at what ever rate I want.

Now steam is building pressure and holding at 5 PSI in the boiler; at the point where the steam is leaving the system the pressure is 2.5 PSI.

That is how this could happen.

If you look at the Weil McLain glass pipe boiler you can see dry steam leave the system to the parking lot when the valve is partially opened. But when the valve is opened more, the wet steam and water will exit the system into the parking lot. Weil McLain's example can be made to show the different velocity of steam leaving to the system into the parking lot by opening the valve less or more to show the point.

Does that help a little Paul?

ChrisJ

How is there 5 PSIG in the boiler but only 2.5 PSIG in the steam main?

Is a valve being throttled?

EdTheHeaterMan

https://forum.heatinghelp.com/discussion/comment/1744074#Comment_1744074

No Valve. Friction loss, it's a gradual thing. There might be 5 PSI at the first elbow off the header, then 4.5 PSI 10 foot down the pipe the 4.0 PSI another 10 foot further… Did you try the 200 ft Garden hose test yet? That will help you actually see it.

ChrisJ

https://forum.heatinghelp.com/discussion/comment/1744076#Comment_1744076

No,

I'm not going to try an experiment using 200 feet of 5/8" ID rubber hose and water. I'm well aware of friction losses. In fact, I calculated what they are to each of my radiators around 9 years ago.

But I think trying to achieve 2.5 PSIG of pressure drop using a gas through 2"+ iron pipe would be an impressive amount of flow.

ChrisJ

Here's my drawing from years back.

EdTheHeaterMan

Nice drawing Chris. Nice calcuation too. Im guessing the steam velocity in those pipes were very slow. And yes to drop pressure of 1/2 PSI in just 10 feet in a 3" pipe would be a very fast flow rate for the steam. But not impossible over a longer pipe length and a higher BTU boiler than your 104K. I was answering Pauls question about a bigger boiler when you asked about dropping grom 5 PSI to 2.5 PSI. Your boiler does not qualify as a bigger boiler. But the answer does not mean that it will happen to your boiler. However your reply does not rule it out completely because that does not show what could happen with a failure. It shows what does happen under normal conditions.

The reason any rule is in place, be it a recommendation or a hard fast code regulation, is because somewhere, someone, at sometime past, had a problem, property was distroyed, persons were injured or someone died. Then after that, a group of people sat around a table and took time to figure out what went wrong. After they figured that out, they asked the question… How do we keep that from happening again? There is a complete story about that and how they designed the equalizer and Hartford loop. You should read it some time.

ethicalpaul

https://forum.heatinghelp.com/discussion/comment/1744073#Comment_1744073

No, sorry, it doesn't. I think the answer to my question does not exist. There is no condition, with a boiler used for heating that has a main with a drop to a wet return, operating more or less normally, where the boiler will push water out the back into the wet return. The examples of hoses and the WM parking lot boiler and process boilers just don't apply, but thank you for sharing them!

EdTheHeaterMan

But you do agree that there is a pressure difference from one end of the system (the boiler) and the other end (the end of main that connects to the return) and therefore there is a need for the Dimension "A"

ethicalpaul

No. I see no evidence for that, and none has been presented. We both watched my boiler go up to 5psi with no raise in water level whatsoever.

Yes my boiler is small, but as boilers and systems increase in size, the piping size is increased to handle the additional flow of steam. Since the systems are engineered to be able to deliver as much steam as they produce which is equal to how much the radiators need, I see no way for this event to occur.

Not even in the Empire State Building which, as we have been told, operates at 1.5-2.0 psi just like everyone's home systems do.

ethicalpaul

When I drew my pictures at the start of this thing, I figured there must be a pressure difference of note, that's why I drew the pressures along the main to the end as "< 5psi" because it seemed to make sense at the time, and the literature certainly pointed to it due to its concern with Dimension A.

But now that I've really looked at it in practice and with varying the pressure, and even with valving off my equalizer, I just don't believe it anymore, not for boilers of the design we are speaking of in this forum.

As I mentioned a couple times recently, I think people mistook surging and the resulting drop in boiler water level for pressure pushing it out.

EdTheHeaterMan

I think that we would be hard pressed to find a boiler that was installed over 120 years ago still in service. So I think that we will be equally hard pressed to find a boiler operting with a desigh that might come close to illustrating that the pressure in a boiler can get high enough to force the water out the return and cause it to stack up in the dimension "A" area of the system. That is because any of those boiler systems have been replaced sith domething new that includes the Hartford or Gifford loop.

All I can say is that there must have been some type of problem that the boiler men/women* at the time needed top solve wnd they came up with what we have today.

*Added that for the benefit of @Subdural Did you see the piping she installed on her boiler… WOW!

T

ethicalpaul

The gifford or hartford loop don't seem to affect pressure of the system at all so I'm not so sure about that Mr. Ed 🤔

The current designs are what is in TLA and the current designs are the ones where people are talking about the water getting pushed out of the boiler, so I think I'm talking apples and apples there.

Yes, I saw it, that was fantastic work

dabrakeman

Wouldn't downstream steam pressure loss (assuming there is any) be more a function of the steam condensation than of friction? There is a 1600:1 volume reduction happening. Potentially much more equivalent to opening a hose😏

ethicalpaul

yes. Friction is immeasurably small in these systems.

I thought of a way the far water line (if I may call it that) could rise.

You know that recent post about the 2 million btu boiler with a single 4" supply? That kind of piping error might cause it due to constriction just like when I throttled down my supply valve. But that is a serious piping error and of course the EQ wouldn't help that

SuperTech

Hey Paul, I just want to thank you for taking the time to perform your experiment and for bringing up this question in general. As someone who rarely gets the opportunity to work on a steam boiler I've often wondered why the equalizer is named as it is. Your experiment has been interesting to say the least

EdTheHeaterMan

https://forum.heatinghelp.com/discussion/comment/1744130#Comment_1744130

It has certainly made me re-think what I already "Know for a fact" about what I was taught so long ago. How can we really know anything if we don't question it from time to time. But I still believe the earth is the center of the universe… and it is flat. I have supporters around the globe who agree with me! https://theflatearthsociety.org/

EBEBRATT-Ed

While it is true that the drop to the wet return at the end of the main acts as an equalizer and balences the pressure between the supply and return I have seen air vents spit water without an equalizer.

A homeowner had his boiler replaced where the boiler had failed . This system had been knuckleheaded previous to the new boiler install by the homeowner having someone remove the cast iron radiation and installing finn tube baseboard in it's place…….not a good idea. He had been having constant problems with the baseboard air vents spitting water and and not heating…..this was 1 pipe steam and the baseboards were not pitched enough and some of the basebords were very long.

The "fix" we did was to install a return line from every baseboard in the house (each run as a dry return) back to the boiler and then dropped down all the returns were connected below the water line and the air vents were taken off the baseboard and relocated to the top of each drop.

The system then heated well but the air vents kept spitting water.

At tis point the boiler had been installed without an equalizer so we installed one and the spitting stopped immediatly.

This was back in the 70s soI don't remember anything about skimming or haw the header was piped or what pressure if any it was running at…….this was a tiny ranch jhouse. But I distinctly remember installing the equalizer and the spitting stopping.

ethicalpaul

While it is true that the drop to the wet return at the end of the main acts as an equalizer and balences the pressure between the supply and return I have seen air vents spit water without an equalizer.

So you DO think that the equalizer can affect the height of water at the far end of the wet return and you were gaslighting me this whole time, I knew it! 🤣

Do you think it could have been surging and not water level rise at the far end?

PhilKulkarni

Ethical Paul, your videos prove your point about the function of the equalizer, I mean a lack thereof.

On my 66' mains, including the dry return my boiler water level of the sightglass ht in approx 7 mins from a warm start drops to 25% of the NWL at a pressure of just over 0.5psi. After this initial drop, water level in the sight glass varies +/- 0.25" until the boiler shuts down on temp.

My PB boiler- one size larger than yours- holds 13 gallons, and based on the external geometry, I am estimating anywhere from 3-3.5 gallons are being expelled into the wet return causing the water level in the boiler to drop. Since my A dimension is 33", the water in the wet return does not block the main vents.

Thus, my equalizer is unable to keep the NWL stable. I have checked and rechecked the oft mentioned maladies here-surging, sagging pipes, improper near boiler piping, leaks, condensation in the rads creating a vaccum, et al, but can't attribute the pressure drop across the mains to any of these except friction.

The frictional losses which result in a pressure gradient across a steam carrying pipe are a function of the steam dryness, viscocity, temperature, velocity, pipe length, pipe cross section and other constants, with steam velocity being the largest contributor. Which of these factors are affected by an equalizer except steam dryness?

Your equalizer has a minimal impact on steam dryness but for the majority of us, steam/water seperation is a compelling reason to have one. I agree with you that the equalization of pressure is being done by the mains and the wet return.

FStephenMasek

How about simulating a failed wet return to see what happens with the equalizer not present (with careful fiull-time monitoring, perhaps in a proper laboratory / experimental setting)?

ethicalpaul

@FStephenMasek I don't need to do that experiment, I think everyone agrees what will happen is the water will drain out of the return and the boiler.

Thanks @PhilKulkarni . Your description interests me:

I am estimating anywhere from 3-3.5 gallons are being expelled into the wet return causing the water level in the boiler to drop. Since my A dimension is 33", the water in the wet return does not block the main vents.

Surely if your boiler is pushing out 3-3.5 gallons, that would push the water up to your main vent? What size is your end-of-main drip pipe to the wet return? If might be less water than you think. Or the possibility does exist that you might be surging.

STEVEusaPA

Just wondering if Dan has weighed in this thread or your other thread. Would like to hear his insight too.

EBEBRATT-Ed

The water in the return must rise up to create a pressure differential to push the water back into the boiler. You need a pressure difference to make the water move. Your working with low pressures so the pressure readings will not vary much

ethicalpaul

I was running all the way up to 5psi during my experiment, Ed.

I'm sure the water level at the far end was always slightly higher than at the boiler, but it was all balancing out very quickly.

As condensate runs down, yes it momentarily raises the level there, but then the additional weight pushes water into the boiler.

The thing that surprised me, was I could never see any visible raise. At the beginning of all this I suspected I'd see a pressure differential that resulted in a rise there, but no, never could see it.

Steamhead

According to chapter 5 of @DanHolohan 's "The Lost Art of Steam Heating", the equalizer was originally called a "bleeder". It was intended to replace a check valve in the return line so the water would not back out of the boiler if a return line broke. Remember, in the days of coal-fired boilers, there were no low-water cutoffs. It's easy to forget how good we have things now.

The problem with check valves on return lines is that they could stick or leak. The bleeder did not have that problem.

It's true that, in normal operation, the equalizer isn't needed. But the same can be said of Hartford Loops, low-water cutoffs, pressure controls, pilot-safety controls, oil or gas primary controls and many other things. We install these, not only because Codes and manufacturers' instructions require them, but because they just might be needed some day- or night, when no one's around.

ethicalpaul

I get that, but in my reading of TLA, it doesn't say "in case of a wet return leak". It says just generally that the equalizer keeps water in the boiler and prevents pressure from pushing it out. That was the thing I never could understand, and the reason for this whole discussion.

I'll read the chapter again, but if you can point me to the page you're looking at @Steamhead, I'd appreciate it!

Steamhead

https://forum.heatinghelp.com/discussion/comment/1744615#Comment_1744615

In the original edition, pages 61-63.