Equalizer disabled experiment video

Tim_D

A couple ofthoughts. and questions,

1) The boiler took what seemd to be a very long time to make pressure against what you described as a significantly derated system. Why?

2) The equalizer is intended to equalize pressure at the tee in the Hartford loop only. The other benefit of the equalizer is of course the ability to drain away condensate and carry over in the header. The equalizer is not necessarily intended to equalize pressure across the entire system. Physics will do that. Think of the system and all of its components as a big metal balloon. The laws of physics tell us that pressure will be exerted equally in all directions. Yes there are friction losses in the piping which consume energy but given the large pipe diameters and fluid density as compared to a hot water system, the overall effect is minimal. This rise in the water colum in the return is a function of the need to build enough pressure by virtue of the weight of the water, to overcome the boiler pressure. The equalizer has no role in determining the required height. Open every radiator with your cut in at 3psi and bad things are likely to happen with the equalizer open or closed.

3) with a significantly derated load you are not producing the amount of condensate that would be expected in normal operation given the rated capasity of the boiler

4) Between 1879 and 1891 there were 2159 steam boiler expolsions, thats one every 48 hours! 4352 serious injuries were recorded and 3123 lives were lost. In 1919 the hartford loop was introduced with one purpose and only one purpose, to help keep a minimum amount of water in the boiler. Steam boiler expolsions with a Hartford Loop in use appear to be so rare that I am unable to find any reliable figures.

5) My dad started in the trade in 1939 and worked with several of Dan's "Dead Men". These guys knew steam. I started in the trade in 1976 although I had already been helping Dad as often as possible for many years. We both worked for Mr. Robert T. Cameron who started in the trade in 1924. He knew steam! Dad and Mr. Cameron paid meticulous attention to detail in their near boiler piping which always included a Hartford Loop. These men forgot more about steam than I may ever know. I have been replaceing steam boilers, maintaining steam systems and supporting those that do this work for over four decades now and I always do things the way that I was taught and it works. I see plenty of systems that are not piped the way I was taught and they are alomost always problematic. Got to be something to it?

6) Curious, how far above the water line was the sight glass in the return?

Thanks for being inquisitive, the great video's and making us all think!!!

ethicalpaul

Thanks @Steamhead I'll go look, although I have the revised edition, but I'm sure those pages will get me close.

Thanks for the points, @Tim_D ! I'll address them below:

1. it took how long it took 😅. In the second video the system was pretty cold so the steam had to heat up the main and all the runouts, that might be most of it.
2. You're preaching to the choir here, it wasn't me that was saying the equalizer affects those things.
3. I would have to disagree with you here. My boiler is creating the same steam regardless of what my radiators are doing. I didn't derate the boiler, I just disabled some radiators. So the condensation is constant once operating pressure is met (it is likely very slightly less as pressure is rising). But let's set that aside. What are you saying would be different with less condensation created?
4. The hartford loop isn't responsible for that decrease in boiler explosions, improvements in LWCO are. The best the hartford loop is keep some water around a few minutes longer. The steam-producing process will still run the water out of the boiler. But this whole discussion is not about that. See my discussion from 2019 for that. All this is about is me wondering how the equalizer could keep water in the boiler under normal conditions, which was presented by folks as fact, and also I believe it was presented by TLAOSH as well.
5. I wasn't making any arguments in this discussion about how piping should be changed. I like the equalizer.
6. It's a couple inches higher.

As a reminder, here is what my copy of TLAOSH says:

1. A Hartford Loop is an arrangement of piping between a steam boiler’s header and its gravity-return piping. 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

.

The “wet” gravity return line, which returns the condensate from the system, rises up from the floor to join with the equalizer at a point about 2 in. below the boiler’s lowest operating waterline.

2. The Dead Men didn’t always use this piping arrangement. They used to bring the return directly back into the bottom of the boiler without the benefit of either a Hartford Loop or an equalizer. When they piped a boiler this way, however, the slightest steam pressure would push water out of the boiler and into the return. They solved this problem by using a check valve in the wet return (that’s the pipe below the boiler waterline).

Before long, though, they found the check valve would fill with sediment and get stuck open. That caused the water to back out of the boiler again, so they developed the equalizer pipe to replace the check valve. 

Whatever pressure appears inside the boiler will appear inside the equalizer pipe

 — if you size the pipe properly. The two forces balance each other and the water stays in the boiler.

ChrisJ

https://forum.heatinghelp.com/discussion/comment/1744608#Comment_1744608

So my assumption is actually correct.

The equalizer is just a vent so the loop doesn't siphon from the boiler. It's exactly the same as a plumbing vent intended to keep from pulling traps dry.

Without it, the loop does absolutely nothing, it'll just pull the water over the hump.

Tim_D

LWCO's were not invented until the late 1920's and are not 100% reliable or soley responsible for the decrease in steam explosions. I could not begin to count the number of float type LWCO's that I have found over the years, full of mud and stuck so that they would never indicate low water.

Tim_D

You derated the load and therefore the ability of the system to create condensate. Less surface to transfer heat equals less condensate. To my first question, something seems amiss when you have radiators closed and the boiler still takes that long to make steam. Did you use the valves at the radiators or are there valves in the risers? Radiator valves are not always capable of 100% shut off.

ethicalpaul

https://forum.heatinghelp.com/discussion/comment/1744645#Comment_1744645

Yes I decreased the load, but no one told my burners. They are still creating steam at the same rate, and therefore the condensation is the same rate. Everyone's radiation load is dramatically reduced at the start of steam production because the radiators (and even the runouts) are all still full of air. But condensation continues, no?

The boiler didn't take longer to make steam in my videos. It was making steam just like it always does.

On some of my radiators, I have a valve under the vent and if so I used that. A couple of them have new supply valves that do seal quite well, that's what I closed on those ones.

ChrisJ

https://forum.heatinghelp.com/discussion/comment/1744644#Comment_1744644

I suppose that mattered when someone was tending the boilr and checking it / feeding it every once in awhile. Like in the 1920s.

Now you have boilers with autofeeders (sometimes) that no one pays attention to at all.

Even my boiler, no autofeeder and I still only check on it every few days which i'd bet is far more than normal. If the wet return leaks that Hartford loop buys me time, but not much and it's highly unlikely anyone will check on the boiler before it dry fires.

I'd still bet multiple LWCO's are a far better option these days. No floats, two probes.

ChrisJ

Keep in mind.

Every time Paul brings up this subject everyone attacks him. Not once has he said to go against code.

Yes, Hartford loops are required by code and most certainly must be installed unless that code changes.

But there's another part to this. Besides simply better understanding what we're doing and why we're doing it there's something possibly far more important.

When I started looking up info about security cameras there were warnings not to install fake ones because they gave people a false sense of safety. People tended to change their behavior belieiving they could rely on cameras that actually did nothing for them.

If the Hartford loop does indeed make us safer that's great. But, if it gives a false sense of safety that isn't really there, that should be well known and understood. Not just assumed.

Perhaps we rely on LWCO's far more than we think.

ethicalpaul

https://forum.heatinghelp.com/discussion/comment/1744644#Comment_1744644

I believe you. Now how many explosions did you see prevented by the hartford loop? How many dry-fired or cracked boilers have you seen that had a Hartford loop?

Not that this discussion has anything to do with the hartford loop!

jdirenzo

Your system has very little pressu re drop and probaly enough of a water column to over come the small difference.

JohnNY

Funny how the Hoffman Specialities literature gives that pipe two names.

ethicalpaul

https://forum.heatinghelp.com/discussion/comment/1744751#Comment_1744751

I ran it up to 5psi in the video and I have a sight glass on the drop…it didn't rise even an inch. What kind of systems do have a pressure drop? What causes it?

KC_Jones

https://forum.heatinghelp.com/discussion/comment/1744751#Comment_1744751

Most if not all steam systems have very low pressure drop.

2" pipe with a steam flow of 25 FPS has a pressure drop of 0.1408" of H2O per 100'. Given that I'm left scratching my head at all the comments talking about all this pressure drop across the system and how that would make things different. I mean how much pipe and fittings are people seeing in these residential systems?

Hap_Hazzard

https://forum.heatinghelp.com/discussion/comment/1744754#Comment_1744754

I assume that's because the two-pipe system has a check valve, so it doesn't need an equalizer, but it still needs a header drip.

SteamingatMohawk

Please see my attached writeup on friction flow losses in steam.

PMJ

SteamingatMohawk said:

Please see my attached writeup on friction flow losses in steam.

Thanks for the confirmation @SteamingatMohawk. I have known for many years now that no measurable pressure in the header is required at any time to heat in these systems originally designed for continuous coal fire. If there is no pressure in the header then there is no pressure drop getting to the radiators. Fractions of an ounce at most. So measurable pressure in the header means the whole system is pressurized. It also means money is being wasted.

EBEBRATT-Ed

@JohnNY I think the addition of the condensate pump changes it from equalizer to header drip

EBEBRATT-Ed

Don't forget not all boilers put out dry steam as @ethicalpaul does. Remember the Weil Mclain videos with the glass pipe that threw ton of water up into the main and you needed the equalizer to get the water back into the boiler?

I would prefer in most case more risers and increased riser size to keep the water in the boiler so you don't have to rely on oversized or drop headers to return the water to the boiler. Water that it shouldn't be leaving the boiler in the first place.

If you have a boiler with overhead dry returns or main extensions ( @Jamie Hall ) and a boiler that puts out dry steam you probably don't even need a header drip or equalizer.

With wet returns I think a hartford is important because for the cost of a few nipples and elbows you might save a boiler ....low water cutoffs do fail and are often neglected.

As far as the return water backing out of the boiler and water level rise in the return drop don't forget that most boiler are oversized for the connected load especially with a 33% pick up factor built in.

What does that have to do with things? A lot.

A boiler can't put out more steam that the radiation connected to it (except on a cold start) when your heating the piping or the temp in the building is way low. Low flow means low pressure drop in the piping so if there is low pressure drop in the main the return water level may not need to rise.

But don't forget:

Not all systems are piped correctly as is @ethicalpaul

And not all steam system are installed in houses

Picture a church heated intermittently or a school or large apartment building. The pressure drop in the mains is likely higher, many time the pipe is uninsulated and longer runs of piping require the equalizer to balance out the boiler supply and return pressure.

JMHO

KC_Jones

Several of us have posted the actual numbers of pressure drop in a main and the response by some has been, “well some other thing might be different so our point is still valid”, or some derivative of that.

Fine, please post your calculations that show how high the pressure drop can be in a main to refute our calculations that show it’s basically zero in virtually every steam system out there.

If you look at my previous post stating at 25 FPS the pressure drop for 100’ of pipe is .1408” of H2O, then to get even 1 psi of pressure drop would take almost 20,000’ of 2” pipe. That would be a huge church, actually I’d suggest there isn’t a church that big on planet earth.

So, again, for all those talking about pressure, show me your numbers, let’s stop with the conjecture. Oh and as a final reminder no where has Paul ever suggested eliminating the equalizer, he fully supports the existence of the pipe.

ethicalpaul

it makes a great header drip!

ChrisJ

My opinion as of right now is people need to start considering multiple LWCOs more,

Curious if anyone makes an optical LWCO that mounts on a gauge glass?

Matt_67

I suspect that when the Hartford loop came into existence the boilers it was actually needed on had both heating and power loads. Electricity and internal combustion motors weren’t as common in the late 1800’s and early 1900’s. So if a shop had a steam driven motor come on line I could see the return pressure dropping suddenly and pushing the water out of the boiler. I’m guessing the requirement spread to other boilers where it’s really not needed.

ChrisJ

Matt_67 said:

I suspect that when the Hartford loop came into existence the boilers it was actually needed on had both heating and power loads. Electricity and internal combustion motors weren’t as common in the late 1800’s and early 1900’s. So if a shop had a steam driven motor come on line I could see the return pressure dropping suddenly and pushing the water out of the boiler. I’m guessing the requirement spread to other boilers where it’s really not needed.

Are boilers driving steam engines ever gravity return?
I don't see how they could be?

Matt_67

They would also have had heating loads on the same boiler, just like an industrial plant today. Some condensate wasted, some returned.

ChrisJ

Matt_67 said:

They would also have had heating loads on the same boiler, just like an industrial plant today. Some condensate wasted, some returned.

I understand that but how does water return to a boiler running at 100 PSIG by gravity?
I have absolutely no experience with industrial steam.

SteamingatMohawk

Here's another calculation:

Matt_67

Today it’s all pumps like you say. Paul’s video shows that the pressure doesn’t affect condensate return if there isn’t pressure drop at the wet return. What I’m imagining would be a wood or coal fired boiler that can’t react quickly to load changes, or perhaps severely undersized piping. They were still figuring out things back then and my guess is they required the Hartford loop to protect against unintended consequences.

ChrisJ

Matt_67 said:

Today it’s all pumps like you say. Paul’s video shows that the pressure doesn’t affect condensate return if there isn’t pressure drop at the wet return. What I’m imagining would be a wood or coal fired boiler that can’t react quickly to load changes, or perhaps severely undersized piping. They were still figuring out things back then and my guess is they required the Hartford loop to protect against unintended consequences.

No,
I don't think that's what Paul's point is.

Yes, the Hartford loop did protect boilers from suddenly dumping all of water all over the floor. Without a LWCO and having people tending to a fire throughout the day this probably made a big difference.

Paul's point here is the equalizer doesn't stop the water from being pushed out of the boiler by pressure while operating. It's a vent so the Hartford loop can work. Without the vent, it would siphon out of the boiler over the hump so that hump would be 100% useless.

Perhaps everyone has been looking at the name equalizer completely backwards. Perhaps it equalizes the pressure between ends of the system under vacuum conditions (Siphoning from broken pipe). I don't know, I don't know where the name came from or why.

Paul never said it shouldn't be done, or that it doesn't help. He's trying to point out it's not doing what everyone thinks it is. He's even going as far as to actually test this, to the extent he can.


As far as steam engines, I don't think they ever could have returned water by gravity. I believe most used an injector that used steam to blow condensate back into the boiler. I'm pretty confidence The Titanic, nor The Big Boy had hartford loops.

Matt_67

My main thought was just that the origin of the Hartford loop and concept of an equalizer likely wasn’t from heating only boilers. It was probably from a boiler that could experience a drop in pressure and that’s more likely with a power boiler. I doubt the typical smaller industrial facility even tried to return condensate from driven equipment, but they could have from portions of the system used for heating. If the pressure at the end of the main dropped suddenly due to an operating condition the Hartford loop kept the water in the boiler.

On another note there is a Big Boy in the railroad museum in Green Bay, Wisconsin. I think they carried like 25,000 gallons of water in the tender. It’s pretty cool to see the valves they had to adjust to run that engine, it sure makes you respect the engineers that operated it.

EBEBRATT-Ed

Which is my point exactly. There are many different applications of steam boilers for all kinds of heating and process jobs. Most of us tend to think houses which may be the most common but also the most benign installation.

The Hartford was originally for coal fired boiler with no low water cutoff. It can still serve that purpose to protect the many neglected boilers with non-working or neglected LWCO who's owners/operators don't test them or even know they don't work.

We all know that a boiler fed by a boiler feed tank or condensate pump needs no Hartford loop.

So the question is we need a header drain especially if the boiler produces wet steam (again, maybe neglected or not skimmed or piped right)

It seems to me that because the hartford can have some low water protection and the header drip may be needed especially with wrongly piped or neglected boiler it just makes sense to install them as is usually done as especially if it is not your house you don't know how it will be neglected down the road.

As far as the equalizer aspect I have seen boilers push water back into the returns. JMHO I have seen it happen. This is why some old jobs had check valves on the returns which is not the best fix, but they put them there for a reason. The old timers counted every fitting due to cost and were not going to waste money on brass check valves for no reason.

Can I prove that a boiler will push water out the return with no equalizer.....yes under some circumstances.

What about a job with steam zone valves? Many of them exist rightly or wrongly.


Can anyone say a job with multiple zone valves won't push water out the return into a zone with it's zone valve shut?

On the other hand I have seen many old steam jobs with no header, no header drip or equalizer or hartford loop juts a supply pipe and a return pipe like a hot water job and they worked fine.

The boiler is the boiler and it's the boiler and the system it is connected to that have to work together. Not all systems are the same.

It's easier to install it the way the mfg recomends. You don't need safety controls or fuses or anything until something goes wrong.

SteamingatMohawk

Plus, if something does go wrong and the boiler isn't piped per the manufacturer, the insurance company may not cover any loss.

SteamingatMohawk

@EBEBRATT-Ed I am curious, since there is essentially no flow pressure drop to cause water to leave the boiler, what is happening? The only thing I can dream up is condensation of steam in piping that no longer has any air in it, causing a vacuum (assuming the vents have already warmed up and shut.

ethicalpaul

Just to refocus, I never said there shouldn't be an equalizer. What I questioned was the idea that the equalizer somehow keeps water in the boiler, preventing it from being pushed out into the wet return.

The only way I could force water to exit the boiler in my testing (and I admit I only have a single small boiler to test with, but it is a typical boiler!) was to close the steam supply valve to almost closed.

This would be similar to what would occur with a zone valve as Ed mentions...if you had a zone with its own supply and wet return, if you close the steam supply, you will lose the true equalizing effect of the main, and yes water will leave the boiler so I can see why they would need a check valve or very low pressure, or some other solution for that setup (as described on pg 63 of TLAOSH). It is here that Dan points out that it is what he calls the leftover steam at the end of the main that keeps the water from rising at the far end of the wet return. I agree with this, and had formerly stated that I felt it was the Main itself that was acting as the true equalizer (this is before I saw the similar statement in TLA today but certainly I must have read it before).

HOWEVER, the presence or absence of the EQUALIZER in that scenario would not affect anything either way.
Do we agree?

This appears to conflict with TLAOSH page 103-104 where Dan describes the Equalizer/Bleeder function as follows:

Now when the steam pressure in the boiler tries to push the water out, there's an equally powerful force pushing it back in. That force holds the water in the boiler and does away with the need for a check valve.

It also makes Dimension "A" independent of the boiler's pressure. With the bleeder, Dimension "A" is now free to deal only with the system pressure drop.

I feel this is an error in TLAOSH. Both drawings in TLA on page 103 and 104 (the one without an equalizer and the one with) would result in the same behavior--the main keeps the level at the start of the wet return in check.