Another Slant Fin Steamer....Defying the Rules

Christian Egli_2

Our Dan Holohan somewhere has a wonderful description of something the Victorians were fond of: the radiator sack. It was an object of endearment, you'd cut one out of velvet, you'd add fringes and drawstrings and for the ultimate frill, a little doily would crown the whole montage. That was the time of glorious heat.

How will you outdo your vain neighbors with their big radiator sacks if you don't have even larger radiators installed in the first place? This all points to how a coal fired system was meant to be overradiated for most of the system operation, while full radiation came on with only a raging wood fire or an overenthusiastic husband stoking the boiler on the weekend.

So there, I don't think the pick-me-up lines were ever meant to work in absolute fashion; it all... depends. What the rules do, though, is guarantee that the promises of fully hot radiators can be fulfilled. That's important, but if you change the promise, you can change the rule.

Add the historic fact that we all get butterflies when thinking of a replacement boiler that is not at least the same size or bigger than the old one, and there you go, reversing this gluttony in the plus size department is about as terrifying as the thought of giving up doughnuts.

When speaking of steam, I think it helps to not worry about steam production so much as to worry about the eviction of idle air. When steam is strong enough to push back against the bullying air, it all works the wonderful way we know, the air comes out with a black eye.

On undersized boiler set-ups, the smaller sized cloud of steam will still form and it will still hang around the header, and just like a full complement of steam, it will still push itself down the pipes. But, with a weak boiler, the push becomes a struggle and it's only a struggle because of the air vents.

The air vents, with their tiny holes are the bottle neck to prevent unencumbered air flow. A slightly underradiated boiler can build the pressure to force out the air. You can suck out the air with a vacuum pump, it builds pressure by going the other way. While an overradiated boiler cannot build pressure unless air vents are either so small, or clogged, or shut that air can't escape at all; then, you'll get pressure but no radiator heat.

Air vents on systems that have a low low low pressure differential to move the steam around (such as an underpowered boiler) need to have big big big open air holes.

Two pipes work ok on grossly undersized boilers because they still achieve air elimination quickly. The radiator thermostatic traps have big holes which open into free returns which themselves open freely into the atmosphere (I don't follow the use of thermostatic air vents on the dry returns after the radiator traps). It all works even better with a vacuum pump sucking the air out faster than it would rush through a straight open hole. The air is shown a wide open door so that it may leave as soon as it figures out it's not welcome. (and with air sometimes you wonder... if only it were half as smart as steam... well, at least it's good for breathing... :)

The beautiful Mouat systems, a take on the one pipe systems with added separated condensate return, rely on a hole not unlike the hole of an air vent to pass the air. Only, the hole is big, the combined pilot/equalizer hole and the whole throat of the p trap provide ample free passage. Chimney ventilated systems suck like a mild vacuum pump.

So there, I think an underboilered, or overradiated system should rely on bigger holed air vents; and not even just a larger collection of small holed ones.

Plus, I would worry about operating temperatures. Most air vents can't tell the difference between hot or even warm air and steam. A slow purging system lets its air get warm as the steam struggles down the main, and if warm air and steam are equally arrested by the vent, you've got trouble.

Of old geniuses: the original undersized boiler was meant to work on a Mouat system. Everything is there to make it work, while what it couldn't handle is the oversize - and for that, dear Mr. Mouat came up with the most ingenious boiler pressure control mechanisms. Gerry, Steve and Terry, it's bliss up there in Mouatland, meeting again would be hot.

Some fun math

Let's say we have a 100,000 BTU/h output boiler and radiators and piping that weigh about 2000 pounds. 6-8 rads, it's kind of believable. How much heat and how long does it take our boiler to cook all this stuff to steaming temperature, about a 150F rise?

Let's see, water eats one BTU per pound and per degree, it's a lot when compared to steel and iron which only eat a tenth of that amount. For the same amount of BTU, you can warm either 10 pounds of steel or 1 pound of water. (and iron is only 7.86 times heavier than water so the heat inertia of water dwarfs that of pipes and radiators)

Let's see how much heat 2000 lbs of water will eat up in preheat

2000 lbH2O * 150 F * 1 (BTU)/(lbH2O.F) = 300,000 BTU

To preheat this huge mass of water (like in a hot water system) it takes three hours of equivalent boiler output to get there. This is monstrous inertia, but unlike a water filed system, this one is filled with nothing.

100,000 BTU/h * 3 h = 300,000 BTU

For the total iron mass, we're only looking at a tenth of the amount, and 3 hours divided by 10 is 18 minutes. Thus, in theory, it takes less than twenty minutes to heat pipes and radiators to a cooking 212F. However, radiators will be continuously cooled by the room itself and may never get to 212F.

But the distribution pipes will. If there is one third the amount in weight in pipes than there is in radiators, then, we'll get our pipes hot in one third the previously calculated amount. One third of 18 min is 6 minutes.

If there is one sixth the weight in pipes than there is in radiators, then the pipe warm up time is 3 minutes.

If you double the boiler size, just for the sake of oversizing, then the 3 minutes is further cut down to 1 min 30 sec.

Steam is quick indeed, providing air gets out of the way.

Boilerpro, I have manufactured new old Mouat vents under the guidance of Gerry's wide experience. Technically, they're not much more than a hole, but what a hole... they're fascinating. Perhaps these would make your system work real well. I'd like to propose something to you.

Meanwhile I'm getting ready to steam the turkey. Best regards to all.

Boilerpro_5

The Rebel in me strikes again

Finally had a chance to put in a steamer in this year. This was one we tried to keep the budget tight, but still give them something that could be easily maintained.

One budget tightening method was to downsize the boiler closer to the expected heat loss of the home. This was especially helpful as we had to dead lift the boiler over a toilet in order to get it to the basement stairs that were only 2 feet wide. Otherwise we would have needed to build the boiler on location. This one pipe steam system had 447 EDR, with one small rad inorperative due to incorrect piping. Pipes are all insulated. The boiler is rated at 120,000 input and 304 EDR.

I made my next discovery why these little boilers make such good steam with only a single little 2 1/2 inch tapping....the supply end section is not only baffled at the steam outlet, with the outlet opposite the connecting section nipples, but the section is about 8 inches wide. Bet that makes for a nice steam chest.

I did some initial cleaning and used Gerry Gill and Steve Pajeks' venting capacity charts to do an initial balancing and tweaking of the adjustable radiator vents. I called the owners a few days later and they said the house is heating very evenly and very quietly in our rather mild weather, with just one properly installed rad not heating well, the same one as before. I still need to go back and install a new thermostat....the current model is not allowing proper cycle lengths and the boiler is short cycling.

The boiler went in nice and quick with two exceptions. The boiler literature was wrong about the vent size, so my helper had to run around to find vent pipe.... not too easy in rural areas. And, as we have discussed here before, the nipple stuck in the relief valve tapping and through the crate was broken off. Fortunately the casting was undamaged. That now makes for a couple of Burnhams, Dunkirks and a Slantfin with this same problem. I wish they would stop packaging boilers this way.

Boilerpro

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ttekushan_3

So what you are saying

> Finally had a chance to put in a steamer in this

> year. This was one we tried to keep the budget

> tight, but still give them something that could

> be easily maintained.

>

> One budget tightening

> method was to downsize the boiler closer to the

> expected heat loss of the home. This was

> especially helpful as we had to dead lift the

> boiler over a toilet in order to get it to the

> basement stairs that were only 2 feet wide.

> Otherwise we would have needed to build the

> boiler on location. This one pipe steam system

> had 447 EDR, with one small rad inorperative due

> to incorrect piping. Pipes are all insulated.

> The boiler is rated at 120,000 input and 304 EDR.

> I made my next discovery why these little boilers

> make such good steam with only a single little 2

> 1/2 inch tapping....the supply end section is not

> only baffled at the steam outlet, with the outlet

> opposite the connecting section nipples, but the

> section is about 8 inches wide. Bet that makes

> for a nice steam chest.

>

> I did some initial

> cleaning and used Gerry Gill and Steve Pajeks'

> venting capacity charts to do an initial

> balancing and tweaking of the adjustable radiator

> vents. I called the owners a few days later and

> they said the house is heating very evenly and

> very quietly in our rather mild weather, with

> just one properly installed rad not heating well,

> the same one as before. I still need to go back

> and install a new thermostat....the current model

> is not allowing proper cycle lengths and the

> boiler is short cycling.

>

> The boiler went in

> nice and quick with two exceptions. The boiler

> literature was wrong about the vent size, so my

> helper had to run around to find vent pipe....

> not too easy in rural areas. And, as we have

> discussed here before, the nipple stuck in the

> relief valve tapping and through the crate was

> broken off. Fortunately the casting was

> undamaged. That now makes for a couple of

> Burnhams, Dunkirks and a Slantfin with this same

> problem. I wish they would stop packaging

> boilers this way.

>

> Boilerpro

>

> _A

> HREF="http://www.heatinghelp.com/getListed.cfm?id=

> 393&Step=30"_To Learn More About This

> Professional, Click Here to Visit Their Ad in

> "Find A Professional"_/A_

ttekushan_3

So what you are saying

is that if you make the proper effort to balance the system, then sizing for heat loss is ok. In other words, if you can assure that, say 75% heating of a radiator manages the heat loss, this is ok so long as things are balanced so that each radiator in the house is roughly 75% heated.

Hmmm. The vents will last forever that way!

-Terry

P.S. Is that water green?

Boilerpro_5

Yep

this is something I've seen on several older systems and it follows conventional venting logic pretty well. You must vent the mains well, but that we know that already. Water is sort of green due to Rhomar cleaner, but I bet its reflecting the bucket.

Boilerpro

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Christian Egli_2

Skimpy steam

Thanks for sharing your experience. I have no problem believing that an underfed system can work, it depends a lot on non discriminatory piping and radiator uniformity and the real pros that work such feats. And if it doesn't work... there are ways to enforce compliance.

One building I have been involved with that was on district steam used to have one big valve downstairs. That was the control, cold? go turn the valve, hot? shut it down a little. Fixed radiators, modulated steam input. It worked reasonably well for years but it wasn't automatic either...

Good going, Boilerpro, as long as the customer doesn't call to complain the radiator isn't fully hot... even though the house is plenty warm and the thermostat is satisfied. That, I think, has got to be the big problem.

My great curiosity would be to know if this actually saves on heating fuel or not. The new thermostat you're going to install will have a lot to do with ensuring fuel savings all on its own.

gerry gill

it will save the fuel

as the t-stat will get satisfied..steve and me have done this too, in steves own house..the thing is that we don't want to teach this method because there will be people who put it in and then disappear..boilerpro took care of the system balancing which is critical to making the system work when done this way..actually steve and me studied boilerpros work prior to doing it in steves house (our laboratory so to speak)..we took out a fine 2 year old IBR sized boiler, and replaced it with 2 smaller boilers sized more than the heat loss but less than the IBR method..he has a credit with the gas company this year.

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ttekushan_3

two boilers

Gerry-

When you set up two smaller boilers, and their combined output is less than IBR, do you always run them simultaneously? My thought was to size a pair at or somewhat above IBR for pickup and shut one down once the pickup load is met. The system can saturate if necessary, or not if not necessary.

Any thoughts of doing this with a two pipe system and using a non-return vent with an adjustable vacuum breaker? Shut one boiler down and operate the system subatmospherically passively, no vacuum pumps. Heat recovered from both boilers with the decreasing boiling temp. Real seasonal ROI there, if properly implemented methinks.

I'd do it myself when (!) installing new steam heat in my home. Of course, I wouldn't oversize the radiation to begin with. My major hurdles are not really technical. Unfortunately, the house is in great shape, the scorched air furnace is old enough to be really well built, the plaster is perfect and the decorating... Well, the family thinks I'm just plain nuts for wanting to voluntarily create disruption. On the plus side, when anyone's about to complain about the chilly house they bite their tongue in a hurry! But when the timing is right...hehehehe....I've been clandestinely assembling all the essential elements to constructing the system >;-)

-Terry

gerry gill

thats the better way Terry..

you got it..we figured that out thru our experiments..we had hoped to be able to drop one out..but since we started smaller we couldn't and effectively heat the house..so we came to the same conclusion you did..you, Christian, Steve and me should get together again some day..we had good discussions last time...i like Boilerpros experimental mentality..we will never learn more unless we ''push the envelope''..

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Boilerpro_5

Glad to here about your results

It sounds like we are beginning to make measured progress here on boiler sizing issues on one pipe steam systems. From my experience nearly all one pipe steam systems are over radiated, and if we can resize boilers to the heat load, or at least much closer, the long smooth burn times have got to add up in fuel savings, rather than having a big monster building pressure on every cycle and bouncing on and off. We end up treating the system more like a coal boiler did and we can vent it the same way.....lots of venting on the mains and just little tiny vents on the rads....Hoffman NO.40 size.

Downsizing boilers on two pipe systems has never really been an issue in my eyes. Somewhere I have that article that T.P. Tunstall sent me about the wide scale success of this technique.

Its places like this that are leading the industry in new directions. Thanks Dan H!
Boilerpro

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Ken_40

I have always thought...

you can "cheat" on net I=B=R steam ratings and actual EDR in place, but never more than 10% and then, only if the pipe insulation was in excellent condition and absolutely "complete" (including take-offs buried behind invisible walls etc.

And yet, I have a Kreibel system we completely restored in North Jersey, made "sing and dance" with huge fuel savings, with an NG boiler older than dirt, UNDERSIZED BY ~30% that heats on a design day withot a cool room in any of the 20+ rooms!

Just shook my head and said to myself, must be the old 150% I=B=R pick-up factor/ratings on the boiler plate allowing us to "get away" with this thing working. However, doing the comparison and discounting the extra 50% completely, we are still 25% under sized vs. the standing radiation EDR!

Does "anyone" (Steam-Head, this means you (;-o) have any hard data and empirical (rather than purely anectdotal) tables, books or archived info on this situation?

Dan, you own every book ever published on steam. Got anything in the museum to shed some light on-topic?

The real limit on this may be the lawyers. I can just hear the plaintiff's attorney, "Mr Contractor, are you aware of what a 'Net I=B=R" steam rating' means on the boiler plate of the boiler you installed"? "Were you aware and did you calculate the standing EDR of the plaintiff's home"?

"Now, please tell the court on what basis you decided to install a boiler that did not meet the proper sizing methods, successfully and scientifically used for the past 100+ years."

Steamhead (in transit)

Ken, as far as I know

no one has done this before. That's why I'm watching Boilerpro's work.

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ttekushan_3

Piping

Really the only time I've found modest undersizing disasterous is where the piping arrangements are very unusual. One instance where the boiler room was 175' from the first radiator. With 3 drip stations. Even taking into account the pickup and running load of that piping (and return piping!) the undersized was just not working. [ran 24/7 october to april. no joke.]

Its time to realize the pick up factor is too arbitrary.

Perhaps the ratio of piping weight to EDR is where we should look. If the piping weight is known, and EDR is known, then we should be able to size 1:1 to the exact load.

I hope this isn't illegal, but if a boiler isn't grossly oversized, I downfire it so that it won't shut off on pressure (1.5 lbs) before about 45 minutes of continous steaming. Under most circumstances this prevents the boiler from ever shutting off on pressure but allows full saturation eventually.

-Terry

Boilerpro_5

Unfortunately it is rather slow...

since I do very few steamers compared to alot of you guys. For that matter, this year I have replaced very few boilers period. It would be pretty easy to experiment with different firing rates on oil boilers just by changing nozzles, etc. and then do a complete system balance. Gerry and Steve's work is encouraging.

Boilerpro

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Boilerpro_5

Yep,

> Really the only time I've found modest

> undersizing disaterous is where the piping

> arrangements are very unusual. One instance

> where the boiler room was 175' from the first

> radiator. With 3 drip stations. Even taking into

> account the pickup and running load of that

> piping (and return piping!) the undersized was

> just not working. [ran 24/7 october to april. no

> joke.]

>

> Its time to realize the pick up factor

> is too arbitrary.

>

> Perhaps the ratio of piping

> weight to EDR is where we should look. If the

> piping weight is known, and EDR is known, then we

> should be able to size 1:1 to the exact

> load.

>

> I hope this isn't illegal, but if a

> boiler isn't grossly oversized, I downfire it so

> that it won't shut off on pressure (1.5 lbs)

> before about 45 minutes of continous steaming.

> Under most circumstances this prevents the boiler

> from ever shutting off on pressure but allows

> full saturation eventually.

>

> -Terry





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Boilerpro_5

Yep,

That's what I look out for. So far I've just looked at home systems, but have run numbers on the btu's it takes to warm up the piping system and the EDR of the piping. It is quite revealing. Our idea of venting the mains in 2 minutes or less seems unrealistic if it takes nearly 10 minute to warm up the piping when its cold and about 5 minutes when its hot. And this is with a boiler sized to EDR.

Boilerpro

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Boilerpro_5

Gerry...

On Steve's system, how did you size the rad vents. For what we're trying to do here, I believe, we need to use the smallest radiator vents available. The radiator venting times should be really long. This allows the steam to head to those big main vents while ignoring the rads at first. I was looking through your charts and it looks like the lowest capacity adjustable vents are the Hoffman 1A's. What I did was match the smallest radiator volumes that needed to be vented with the slowest venting rate and calculate the number of minutes for the vent to completely vent the rad. I think it came out to about 20 minutes for this system. Then I took those 20 minutes and worked backward to calculate the size of the rest of the vents. Unfortunately, the existing vents were all Doles, so the vent rates were not as adjustable at the slower settings as the Hoffman1A. When thinking venting rates on radiators think along the lines of the Hoffman 40's and smaller.
If you didn't vent the rads at these low rates, I suspect that's why you couldn't heat well on a single boiler. Of course, I imagine this concept also has its limits.

Boilerpro

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gerry gill

Hi BP,

on steves system its a mouat two pipe waterseal vapor system..we vent it thru the chimney, or by main vents or by venturi..we usually use the chimney unless experimenting..we can control the steam with the mouat valves, from the inlet side, the way you controlled yours from the venting end..it sounds like you have a good venting strategy tho..

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Boilerpro_5

So, Gerry,.....

when you said you couldn't effectively heat the house, were you simply running out of BTU's available to meet the heat loss or ran into some other limitation? I "undersized" my replacement for that Moline system a few years ago and it worked once I balanced the steam with the inlet valves. I still had enough btu's to cover the heat loss.

Boilerpro

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gerry gill

wouldn't heat the

house enough to satisfy the t-stat..but remember, both boilers online did..and both boilers online were still less than the one taken out..but when we dropped one of these out it was just pushing the envelope to far..we should have done what Terry suggested and start with the proper amount, or even a bit more, then drop one off..but were not done yet..were going to install a low fire valve and since both work well, and one alone doesn't, we will see how 1 1/2 works..

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Boilerpro_5

How about using a simple two stage thermostat

That could be nice. I suspect that to size the boilers so one could be dropped out you would want to calculate the load on a typical day and size the boiler to that load, plus a little bit extra maybe for piping losses etc. Probably use the same sizing techniques as used for staged hot water boilers. Another option would be splitting the load in thirds.
I hope I can get back on that one pipe system from a year ago of so with the 2 stage stat controlling 2 boilers and replace the air vents with adjustables. That was in the plans, but the economy here in the midwest has everybody holding back, except those making big money. The second stage boiler would kick on occassionally on the end of main aquastat as things are now. Also there is still more radiation on line than I planned for. Some radiation was to be taken out of use once the attic got insulated.

Boilerpro

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ttekushan_3

low fire valve

one one of the boilers should do the trick.

And a low fire valve is a good thing to keep in mind for small installations where boilers small enough to do a tandem installation are no longer made. I certainly can't seem to find a 50,000 BTU output steamer anywhere. The low fire valve seems to be the savior in these situations.

ttekushan_3

Christian-

WHAT? {excitement, not yelling}

"I have manufactured new old Mouat vents"

Do you mean steam traps? Like for a two pipe system? If the pipe sizing is right, and boiler firing rate is right, THEN LETS USE THESE and lose those infernal thermostatic traps.

Every time I see these old high-end homes with two pipe steam and, say, the original Crane thermostatic traps and the original gas sectional steamer in the basement, I notice several things if the system is entirely intact:

1) The original sectional gas steamers can really be tuned up with great results

2) They have more mass and are slower steamers,

3) The original steam traps are still functioning or at least have been required to do little work over their [continuing] lifetime since the T-stat's satisfied before saturation. Proof is the lack of saturated steam in any of the dry returns and silent operation.

4) Fuel useage for the amount of actual heat loss is remarkably modest.

When I install the steam heat in my home (sigh...) I want two pipe but no thermostatic traps. Inlet orifices and Mouat style traps it is. And a low firing valve for the boiler.

-Terry

ttekushan_3

And by controlling steam flow

you can use these, carefully.

In speaking with the manufacturer several years ago, they revealed that they had a steam version, but that pitch was critical and I recall that higher pressure set-ups caused big problems. So they were having to send reps out to the job to deal with all of the violated rules of using them with steam. So they're not for steam anymore.

Now, with two pipe low pressure, 'n inlet orifices, and especially the narrow vertical type where pitch isn't critical, well, now we're talkin'.

The manufacturer still says water only with these, but for just the right client and steam specialist, I'd bend the rules.

-Terry

gerry gill

Terry,

Christian has made new main vents..tri-tube type..whichs reminds me, hey Christian i need some of those mouat male adapters..email me.

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Boilerpro_5

Hi pressure goes to low pressure

If we make all the vents real big on the radiators for an overradiated boiler, what will prevent the steam from going to first radiator, filling it, then moving on to the next, etc. We are talking extremely low pressure here, with no vacumn piped reverse return to the supply on the back end to pull the vapor to the end of the system. For two pipe steam with some sort of vacumn device, big vents make sense with the strongest vacumn being at the point farthest fromthe boiler. However, with one pipe, we have no vacuum (unless we set up a Paul system, I REALLY want to try that)so as the vapaor moves down the pipng we need to cause the flow to divide up for each radiator.

I was back at that system today, and with the boiler clean and running full bore with the main vents closed, the rad vents had almost an inperceptible air flow out of the vents no matter what size opening they are. Most of the steam created condenses in the rads creating a vacuum, therfore almost no pressure is created at the vents, just a very slow steady and very gentle push until the condensing steam in the rads equals the output of the boiler. For systems with just a little boiler, large radiator vents will look like main vents. Everything is proportional to the typical way we vent, just much smaller. All the same rules apply. Its just like any other steam system that usually cycles on the stat, not the pressuretrol, the rads have to fill proportionally to the heat loss in order for heating to be balanced.

Boilerpro

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gerry gill

they got the right man

for the job when they called you BP..your going to save them alot of money.

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ttekushan_3

OK. nevermind. I get

a little excitable with that extra cup of coffee.

Boilerpro_5

Thanks Gerry

We certainly need to keep this discusion going. We're talking about something that can have a major impact on our country's energy use and on individual lives. Few people can afford to pay huge amounts of money for heating thier homes, and I hope this is one way we can help them.

We need to keep in touch and hopefully be able to publish our findings and theories together. I just hope I have some more steam systems to experiment with...they are not too common in this area.

Boilerpro

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