Steam Boiler Capacity

Brad White_9

Was the original question one of the radiation, Bruce? Or was it the boiler? I would stick to sizing by connected EDR regardless.

Good to see you on the Wall. Hi to Sergio.

Brad

B. Norian

Steam Boiler Capacity

I have a circa 1927 c.i. sectional steam radiator in a school. It was manufactured by U.S. Radiator and has what appears to be 17 sections. Looking for the output rating as a reality check on my calcs for a new boiler.

Big Ed

EDR

We would need the dimentions of the radiator as well to figure which model radiator.

Order the book EDR from this site .A must have when sizing steam boilers..

B. Norian

The boiler measures 13'-10" x 6'-4". A tag on the front reads: "SIZE WN 282E. The burner is an IC MMG-30

B. Norian

I have measured and added the radiation. I'm a bit surprised that it worked out to 48 Btus per square foot. I just want a reality check on the existing boiler, as I had to guess as to the capacity of large fan coils that serve the gym and cafeteria

Brad White_9

48 BTU/SF

Seems a tad light for connected radiation in an older brick school by itself. I wonder if there are also old pin radiators and indirect heaters since removed? 60-75 BTU/SF would not scare me with ventilation thrown in.

The Industrial Combustion burner takes an input of 3150 CFH gas and 22.5 GPH fuel oil so maybe 2.5 million gross output? Naturally it was likely a coal burning design and I could see it being 150% of that number originally.

As an afterthought, a Mills 4500 in that "mass range" would be in the 3.5 MM output range and it was under-fired (fired to load) since last modification. In other words, taking the boiler size into account, even interpolated, does not add much to the logic tree. It becomes just a point of reference in my opinion.

B. Norian

There's a 4-gang pin fin radiator that heats the ventilation via a fan and lots of ductwork; the fan motor looks like it was wound by Tom Edison himself. I calculate about 700,000 Btuh. What's disconcerting is that although it's the original boiler, circa 1927, there have been adidtions to the building in the 1960s and the 1980s, with the same boiler! Based on scaling a reasonable room layout, the original building was 16,675 sq ft on three floors. The first addition added 21,800 sq ft on two floors; the last adidtion added 13,525 sq ft for a total of 52,000. All with the original boiler! The additions are more than twice the area of the original building.

Brad White_9

That has to be the

best illustration of "heating with the windows open". The design was probably a couple of years older than the building with the Great Influenza on everyone's mind...

Save the plate off that boiler and mount it on your wall.
We will never know how long it might have lasted.

What is the program for this school Bruce? ModCons? Aerco Waltham Standard? Curious. Sounds like a good sound replacement that should save them some fuel regardless.

Brad

B. Norian

The plan is to replace the steam boiler with two steam boilers for redundancy. The long-term goal is to convert the school to town offices, change out the radiation to hydronic and convert the boilers from steam to hot water. Their concern is not economy of operation, but rather, imminent failure of the ancient boiler.

ALH_4

Steam

Just an observation, but it seems like in the long run it would be more economical to make the steam system function correctly rather than converting to hot water. Unless the current system is falling apart, a steam system is not inherently more prone to failure than a hot water system. Retrofitting thermostatic radiator valves could be a very powerful tool in this situation. This sounds like a wonderful opportunity to save them some fuel while providing improved reliability.

Steamhead (in transit)

The U.S. Radiator Co. WN-282 boiler

had a net steam rating of 8775 square feet, and when oil-fired with the burners available then was rated 32.4 GPH. So it's oversized even though the building was expanded. Maybe they wanted to be able to bank the coal fire all weekend, and selected a boiler with a firebox big enough for this?

Don't convert that system to hot-water. It will only be a headache for you. Fix the steam and watch how well it works.

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Boilerpro_5

Another thourght...

Is to continue to use the current steam system and boiler with the added TRV's and then add a baseload boiler to provide enough steam for the typical day load. You'll keep the big old boiler off most of the season and be firing the new boiler verr heavily most of the season for improved efficiency. This also would be a very good place for a modulating burner on a steamer.

Boilerpro

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