First steam boiler replacement.

Dave Stroman

Ok all you steam guys, I am going to attemp my first steam boiler replacement. I have worked on many of them over the years, repiped them and trouble shot them, but this is the first one to replace. The holes the the sections are plugged with wooden dowels.

My first question is how to deal with the float trap/air elimintor and the boiler return trap. The system is heating without any problems. Do I leave these 2 devices alone or should I use a receiver tank and pump. (see first photo)

Next question- Second photo shows the check valves where all the returns come into the boiler. I asume that these check valves, after 80 years, should be replaced.

3rd question- Do I touch anything else out in the system like the steam traps? The radiators are all recesed convectors buried in the walls. The covers are all well painted and have become one with the walls. Since I can not easily determine the connect load, I am sizing the boiler the same as the existing one. The existing one is 440,000 Btus and I thought a 400,000 would work fine. (see 3rd photo)

Your assistance will help get going on this quote.

Dave in Denver

Ken_8

We are envious Dave

This is a "Steamhead-input" showcase inquiry.

Before he married Mrs. Steamhead, Frank was the only 30-year old man I know, who has roamed the spirit world, talking, asking, telling and helping design the vapor systems of yester year. This install has his name all over it. But until he jumps in and tells us which Dead Man designed this system...

The condensate float and air vent thing should be carefully taken apart. Clean all the schmootz and rust outta there and remove the mechanism(s) and clean carefully. Its original design transcends anything you can find today, so keep it if at all possible.

IMHO, there should NOT be checks on the returns. This was probably an attempt to prevent water from backing out of the boiler and flooding the vent and/or dry returns.

If there is now or evidence exists that there once was, a 0-10 p.s.i. pressuretrol on that bad boy - the checks would have been a natural "solution" to a problem that never existed.

You must install a vaporstat on the replacement system.

Regarding the convenctor rads that are "covered"; Try and take a flashlight, lay it on the wire or grill faces and see the rad form and section or width numbers with some accuracy. Using what's there as a basis to size the new boiler may be a very close guess. but the guess is even more critical with a 2-pipe vapor system like this - a true EDR count is the only way to do it properly.

Don't forget your "mile high" atmospheric adjustments too.

The vent and float bodies appear to have "bolt covers." Maybe just undue the bolts and see how bad the internals are?

I'll bet the new boiler

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Steamhead

Lady Steamhead

only makes it better, Ken. I have an out-of-town consulting in a couple weekends and she's coming along. Am I a lucky guy or what?

Dave, I think I remember this Vapor job.... was a very long trip from Baltimore to Denver on that old steam-powered train.... ;-)

The Return Trap and Float Trap/Air Eliminator look like they were made by either Webster or Hoffman. Either way, they were high-quality pieces and if they're working properly I'd leave them alone. The vacuum check in the top of the FT/AE should be removed and replaced with at least one Gorton #2 main vent. That is probably the only venting point on the entire system and needs maximum capacity. If the system still heats slowly you can add Gorton #2 vents to the air line feeding the FT/AE. Be sure to keep the #2 vents away from heat sources that can make them close prematurely.

The check valves in the return are for the Return Trap to operate. They must stay exactly as they are. Clean them out and if they're shot, replace them. See Chapter 15 of Lost Art for a description of how they work- the system in the book is a Dunham but it works the same way.

With a properly-operating Return Trap, a Vaporstat is optional but I'd suggest using one anyway. There's nothing wrong with wearing a belt and a pair of suspenders.....

I'd check the radiator traps by starting up the system, letting it crank out the heat and see if any steam reaches the dry return. It shouldn't- if it does, follow it back to whatever convector has the leaky trap. Replacement trap parts are available from Tunstall or Barnes & Jones- both have online catalogs.

Don't forget to check to see if there are any crossover traps venting the steam mains into the dry returns. If there are, see that they're venting properly and not leaking steam. If there aren't, those mains need their own vents, and you must make sure they are properly sized.

Get a copy of Dan's book "E.D.R." to see what capacity those convectors are. Order it on the Books and More page of this site. Use the results to size your boiler. Follow the installation instructions to the letter. If the boiler needs more than one riser to the header, I'd use a drop header as it's a lot easier to put together. And check to see if there are any "loop seals" at the drip points from the mains that need to be below the boiler's waterline. If so, you may have to set the boiler up on blocks.

Let us know how well you make out!



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gerry gill

i'm jealous,

i want to play too....oh yes, most definitly keep the trap and air vent if they dont leak..i agree with the vaporstat also...who made the return trap? is there a name on it? inquiring minds want to know...you cant get rid of the check valves..they are there for the return trap as steamhead stated..post lots of pictures...

Dave Stroman

Thanks for all the input. The trap is a Webester. I do think that all the air is vented through that one air vent. And yes, I do know that the check valves are a vital part of how the return trap works. I do plan a drop header and a vapor stat. Sounds like I am headed in the right direction. Only question still on my mind is the condition of all the traps. Every convector has one as well as 3 or 4 cross over vent/traps. Hard to believe that they all work after so many years. You know how it is when you work on someones heating system, you are married to it for at least that first year. But the system heats fine so perhaps they will be ok.

Next thing left to decide is which boiler to use. I am getting quotes on Burnham, WM, and Peerless. I will have to put the sections together in the basement, stairs to small for anything else. Denver makes you put boilers on at least a 3" concrete pad so getting the water line to the same level will not be a problem.

What about cleaning and skimming a new boiler?

Dave in Denver

Christian Egli

you're a hero

Hurrah, that will be at least one more steam system that escapes a forced conversion, and I think that's something you can be proud of.

On the issue of pressure control, I am becoming more and more convinced that a lot of steam problems come from the crude way we regulate the pressure. Essentially, cutting in and out with a 1/2 PSI differential is too inaccurate if the goal is to have, say 1 PSI. Lots of things happen, in the way of steam condensating where it shouldn't, while we're waiting for the pressure to drop all the way down by 1/2 PSI and then coming back up at the boiler.

More problems come in to the way when the boiler is oversized, causing a too rapid rise up to design pressure, followed by wild cycling.

So here is what I think: variations from the set pressure should be less than 0.1 PSI, and the rise to the set pressure form the call for heat should be ramped ever so slowly that you wouldn't have to rely only on rapid vents to make the system work. The system could also have a few up and down ramps in the beginning to huff and puff all of the air out. The set pressure should be set as low as possible for the steam to overcome head loss.

Does this all make sense so far? After all, this is exactly the way a coal fueled boiler operates, it is also the way a boiler on a district heating system operates, the fire is fully modulating.

That considered, in a new home heating boiler, I would look for a modulating fire, or at least one with a high / low operation, so that I can be less worried about being oversized and also so that I could use a tight control device on the pressure.

I am actively working on such a control system, I have found nothing within the heating industry but industrial PID controllers are readily available. My problem is more with the gas unit and the relatively long time lag between the electric signal and the time the flames come out in full.

See how I am thinking of ways to get myself in trouble!

I hope everything goes well with your boiler replacement, the home will become the envy of the neighborhood

don_36

Christian

You bring up a good point.I too love steam what little I get to see.

But the one I have seen where the house has been tighten up,
how can one justified keeping a system that is truly way to big for it new home?

Congradulation... Mr Wilsey.

Steamhead

Flush out

all the wet returns while you have them disconnected. Get them as clean as you can. Then when you hook them back up, install some nice big drains so you can flush them again when needed.

I'd let the system run for about a week or so to let it bring all the dirt back toward the boiler. Then flush the returns again and flush and skim the boiler. Include this in the price of the job. Tell the HO to watch the water in the glass and to call you if it gets dirty, and you'll come flush it again.

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Steamhead

Thanks, Don

and that's when you'd want to think about reducing the amount of radiation.

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