Choosing the best gas-fired steam boiler...help?


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Old 01-05-08, 11:59 AM
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Choosing the best gas-fired steam boiler...help?

Hi everyone,

I've read many of the posts in this forum and managed to learn a lot, but I feel like I'm still comparing apples and oranges. Here's the scoop: I have a ~1500 sq ft house (built in 1928) with an oil-fired steam boiler (probably installed in the 1960s). I'd like to switch to gas. I'm finding it very hard to get reliable information about the various boilers, and I'm getting conflicting information from the various contractors that I've had come give estimates. So here are my questions:

1) Are there particular brands of boilers that I should consider? Or avoid? I've read in this forum that I should avoid Weil-McLain (because of neoprene gaskets) and I've heard from one contractor that I should also avoid Crown since they changed their design (recently?). I've had Weil-McLain, Crown, Utica, and New Yorker (made by Burnham) recommended to me. Are there others that are conspicuously absent? If a company recommends a bad boiler should I avoid using that company or should I ask them to install a different model?

2) Does it matter whether copper or cast iron pipes are used? I only have ~10-15 feet to plumb, so I'm not terribly worried about cost--juts repair. I've had one contractor say he won't use copper (because it corrodes) and all the others use cast iron to attach to the boiler then switch to copper. What's important?

3) Of the five contractors that have come out thus far (I'm looking for the right company, not the lowest price), three have measured the radiators (albeit differently each time). One told me that my radiators were 279 (of what, he didn't say, but I'm guessing that it's a measure of the sq footage that the steam "covers"). All five companies have recommended boilers at 112 btu or 150 btu. Is the difference critical? How do I decide? Should I measure myself?

4) I have an unfinished attic that I plan on finishing in a couple of years. It currently has no heat/pipes and would require the equivalent of two average-sized radiators. Can I heat this space with the new boiler? If so, is it best to T off of an existing steam radiator or better to circulate the hot water from the boiler through baseboard heaters? Or something else entirely? And do I need to consider this when I choose the btu for my new boiler?

Many thanks in advance for whatever help or advice you can offer. This site has the best responses of any I've found!

Nikki
 
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Old 01-05-08, 03:07 PM
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I do not like residential steam heating systems for several reasons but the most important for me is that control of different areas (zones) is much more complicated than it is with hot water. There are several other reasons why steam is not a good choice (in my opinion) for residences.

1. I cannot advise you on boiler manufacturers as my experience is with commercial and industrial sized equipment.

2. You will not have an cast iron piping anywhere. You may have some cast iron fittings. You want what is normally called "black iron" piping although it is really steel pipe. Do not allow anyone to use copper piping on a steam system.

3. I doubt that anyone suggested "boilers at 112 btu or 150 btu." They may have suggested boilers at 112,000 or 150,000 BTUs / hour.
Residential steam system boilers are sized according to the number, style and size of the radiators they serve. If three contractors have come up with three different numbers for the installed radiation then at least two of them are wrong. There is another thread here that deals with your situation and I suggest that you read through it carefully. (http://forum.doityourself.com/showthread.php?t=288930)

4. Your attic addition will severely complicate the matter. You cannot guess that it will require "the equivalent of two average-sized radiators" but instead you must do a heat loss calculation to arrive at a real figure on which to base the necessary radiation. Since this heat loss will be dependent upon the size, number and construction of the windows and the insulation in the overhead (roof or attic above the new room's ceiling) and walls it will be difficult to have any meaningful figure until these "little details" are firm.

Of course this added heat load WILL require a resizing of the boiler. It is possible that you can size for the addition in selecting the new boiler yet in the interim "downfire" the new boiler with a smaller burner or smaller gas orifices in the gas burners.

Something else to consider is energy efficiency improvements you may want to make on the rest of the building. These would have the effect of reducing the necessary heat to be added to the house during the heating season. While this IS good for reducing fuel consumption the existing radiation would then be too great for the building and would necessitate smaller radiators which, of course, would mean a smaller boiler would be required.

So, you see, there are a lot of things to consider before purchasing a new boiler.

If it were my home AND I was doing extensive remodeling I would seriously consider replacing the steam system with forced hot water and proper zoning. I'm quite sure there will be others than will disagree with me.
 
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Old 01-05-08, 03:21 PM
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There's a very nice thread from a person that went through basically a similar situation as yours
http://forum.doityourself.com/showthread.php?t=288930
It's 4 pages long but the reading well worth it for what you're trying to accomplish. Take a peek at it if you have not already done so.

Having said that, if I were in your shoes, I'd go with Burnham or Weil McLain. Both make good products.
Not to say that other brands are not good, but those two I'm the most familiar with.

Check them out:
http://www.burnham.com/independ_boiler.htm
http://www.weil-mclain.com/products/displaypro/54-EG

And regarding radiators (beginning in pg-73), here's what's out in the market
http://www.gamanet.org/GAMA/inforesources.nsf/vAttachmentLaunch/70BDB512CD937D9E85256E90006095DA/$FILE/March2004%20I=B=R%20Directory.pdf
 
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Old 01-05-08, 03:23 PM
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Originally Posted by furd
If it were my home AND I was doing extensive remodeling I would seriously consider replacing the steam system with forced hot water and proper zoning. I'm quite sure there will be others than will disagree with me.
I do not disagree - but humbly add that the legacy steam radiation will be woefully undersized when managed with hot water!

So you face a two edged sword - add radiation to the load (perfect time to put in in-floor - lets rip) and install a hot water boiler with correct zoning and control- or replace the steam engine, condensate tank, all that drama - over sized to the anticipated remodel.

hummm Glad I don't have to pull the trigger on this one but I may lean back toward "modern" steam IF -and thats a BIG IF- I knew I had a steam mechanic available to do the job. Not many around anymore. Big bucks either way!
 
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Old 01-05-08, 03:26 PM
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I do not disagree - but humbly add that the legacy steam radiation will be woefully undersized when managed with hot water!
Absolutely correct! What I would do is start from zero and design a totally new hot-water system.
 
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Old 01-05-08, 03:30 PM
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Oh daaaaa

What was I thinking?

What if its a one pipe steam system? Imagine all the return pipe to fit. Oucheeeeeee
 
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Old 01-05-08, 04:46 PM
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Thanks, but definitely not going for hot water...

I like hot water radiators (love the efficiency), but mine is a one-pipe steam gettup, so it's not happening.

Pflor, thanks for the links. I've read good things about the Independence and Revolution (Burnham). Should the same apply to the New Yorker (supposedly same manufacturer, different label)?

And my apologies for the typo--yes, I was told the I needed either a 112K or 150K btu boiler.

Let's see, the first guy measured very carefully (tape measure and counting the I-don't-know-what-they're-really-called bars on each radiator) and he said I needed a 150k btu. The second guy did the counting bit, told me the names of the different styles of radiators that I have, and plugged a bunch of numbers into his computer and told me I needed a 112k btu boiler. Third guy asked how many radiators I had and told me 125k. Fourth and fifth guys both said 150k without measuring. Having read all of the stuff about people over or under-sizing steam boilers, I'd really like to get it right. Is there a way that I can make the measurements myself?

Nikki
 
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Old 01-05-08, 05:22 PM
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For sizing, read the thread that furd and pflor have linked. It's a gold mine.

For the attic, it should be possible to run hot water baseboards off the steam boiler. There are specific ways to pipe for that (tapping below the boiler water line), and it requires a bronze circulator because it's an open system. I don't know how or if that would change the boiler size. A real pro can advise.

As the others have said, steam systems really require someone who knows what they're doing, and those guys are increasingly hard to find. If you are not 110% comfortable with the guys you've dealt with so far, keep looking. A bad steam job is a nightmare. A good one is good.
 
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Old 01-05-08, 07:29 PM
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Wow...

I just finished reading the link that pflor indicated. You're right, it was very helpful (I skipped it before because when I read the first bits, it seemed to be about hot water, not steam). I'm following up some links now to see if I can calculate the EDR. I'm sure I'll be back for more help...
 
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Old 01-06-08, 04:41 AM
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I am not sure if I missed something but the Burnham Revolution is hot water only. The independence has the tappings you would need for a circulated hot water loop. If you are just piping off the boiler you are limited to a maximum of 30 vertical feet. Install a heat exchanger for more than that. The higher you go above the water line the more critical the piping becomes if you are not going to use a heat exchanger. The higher you go the lower the pressure is and it lowers the boiling point of water. Make shure the circulator is pumping up to the radiation.
 
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Old 01-06-08, 06:08 AM
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Independence vs Revolution

You're right rbeck. The Revolution is for hot water only...it was just rattling around in my head for some reason or another. So the Independence is what I'll compare to the other brands.

How do I tell if other manufacturer's boilers also have the proper tappings to run a hot water loop? Or do they all? I'll certainly have more than 30 vertical feet, so I'll make sure that whoever I hire knows to add the heat exchanger. Of course, if they don't suggest it themselves, I'm not likely to hire them for the job, am I?

Thanks for the tips.
 
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Old 01-06-08, 02:13 PM
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The contractor would have to check that. The pipes for the water loop should supply and return at different levels for best operation.
 
 

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