steam boiler replacement- big honking pipe system

Charlie from wmass

Zippy the HB smith G 8 is availible with a gas power burner. This brings it up to the mid 80's for efficency. The burnham mega steam is not yet rated fro a gas burner. Do to the fact you are boiling the water condensing tech will not help you out for gaining efficency.

zippy

steam boiler replacement- big honking pipe system

Some of you may remember this one- It was concluded that I had a 1907 vapor/vacuum system. Appreciated the help on getting it running.

The time has come to start planning its replacement. 150,000 btuh input. two pipe. probably can be downsized. Entire house insulated, lots of new windows. Sp will be subject to a recalc.

I am looking for the most efficient system I can. I have not been able to find residential small system steam boilers that are better than 80% efficient.

Question. What kind of high efficiency steam boilers would be appropriate for this monster?

Unknown

Do you have Dan's books? If not, I would strongly suggest that you get them BEFORE`doing anything. (See "A Steamy Deal" at the bottom of this page)

I wish I'd know about Dan's books before I replaced my steam system as it would have saved me a lot of grief and money!

nicholas bonham-carter

boiler replacement

when you read dan's books, you will see that the size of your new boiler much match the radiator load, and not just be sized according to the heat-loss of the house. when you have got the new one in, assuming it has been correctly installed, you will then realize the savings from your insulation,etc, because it won't run so much. but don't forget the sizing method, or it will actually cost more to run with an under-fired boiler! also specify a vaporstat for your system, as the pressuretrols sent out with most boilers are very inaccurate at the low pressures you need for your type of system.--nbc

Brad White_203

And

you ought to consider the piping size and surface area as "EDR" when you size your boiler. Add that to your actual "radiator" EDR and compare it to your normal "1.33" piping and pickup factor.

My point being, some older systems had piping and pickup factors much higher (1.50 to 1.66 or more) and piping quite large than we usually see going in today.

So to me, it makes sense to take the time and figure the piping as part of the EDR, and compare it to your normal selection procedure. I would hate to have a 1.33 factor boiler fall short on you.

At least you will know.

zippy

I appreciate the advice on the books. They are my bible. I am a step past that. Starting to design the new system. I have been running my steam system for 21 years. It is now an old freind very much in need of a makeover

These old systems are part chinese puzzle....and part chinese water torture!

But thanks for the advice

zippy

The system has a bunch of old air cell on it > asbestos ;-(
> and was thinking about redoing the supply side of the steam with armaflex or fiberglas. How does that affect your thoughts on the loss factors?

Steamhead (in transit)

Steam Mains

Should be re-insulated with 1" thick fiberglass. Some would say even thicker. I wouldn't recommend armarflex for steam.

Got any pictures of your current system?

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Brad White_191

Insulation

Gordo is right- Fiberglass, at least an inch. If you can afford it, anything over 1.5" pipe size should be 2-inch thick insulation by most energy codes. Returns, 1" is fine for most sizes in a typical house, even a large one.

How this affects performance: All piping is cold to start. Once heated, that insulation will knock down bare piping losses to about 1/6th of what it would be.

But for warm-up purposes? I would take the sum of all piping at whatever size it is and cut it by a third maybe. Just a guess, really, and I admit that. You still have to warm up that first round of cold pipe but it will take less time and will retain it longer between cycles.

I probably should expand on what I meant by using the 1.33 factor versus a take-off of piping.

Say you have a house with 500 EDR of actual radiation (120,000 BTUH). With a 1.33 factor, you will have a boiler with a gross output of 159,600 BTUH. So that presumes that the piping would amount to 39,600 BTUH or 165 EDR.

You may find that you have 80 feet of 4-inch pipe (94 SF), 80 feet of 3-inch pipe (73 SF), 60 feet of 2.5" pipe (45 SF) and oh, 60 feet of 2" pipe (37 SF).

All of your piping, if my math is correct, is 249 SF of surface area. Call that EDR. Thus your actual pickup factor is about 1.5- not uncommon for older systems.

Now you would pick your boiler on a gross output of 749 EDR (OK... call it 750), for 180,000 BTUH.

For my net sizing purposes, if that piping were well insulated, I would keep 2/3rds of the piping, call it 167 EDR net add. Thus my gross output would be about 160,000 BTUH.

When you select your boiler, you may find that a different manufacturer might get you a better "fit" than your intended. If borderline or below your target, I would go to the next section.

Steamhead (in transit)

Another possibility

is the Slant/Fin Intrepid witjh power gas burner. We've installed both the Smith G8 and the Intrepid w/Midco gas burner, with good results.

Slant/Fin has certified the Intrepid with Carlin EZ-Gas, HeatWise SU and Midco EC gas burners. All of these are good units. Smith has only certified the G8 with the Carlin EZ-Gas, which is in very short supply right now. So I'd go with the Slant/Fin.

How much EDR do you have?

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zippy

On the insulation.

The basement has no rads. it looks like they intended to heat it by heat loss (I think with this house they may have planned to heat the neighborhood by heat loss!)

Any thoughts about how I should deal with this. I am going to survey, establish EDR estimate and diagramming the system. So When I start working on the redesign I would like to make sure I take this into consideration.

The pipe EDR comments were very helpful

Thanks

The Steam Whisperer (Formerly Boilerpro)

A way to downsize the boiler.....

I have downsized boilers on Moline Vapor systems simply by adjusting the orificed radiator valves to balance the system. You could do this with any two pipe system by adjusting the valves, but better yet add steam orifices to the supply valves. Do an internet search on Frank Gifford...he has hundreds of two pipe systems he has done this with and has written an article on the procedure. You can get orifice plates from Tunstall Co. just for this purpose. You can match each radiator capcity in each room to the new heat loss of each room.

Boilerpro

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