Sizing Boiler to Radiators

Ryan_9

Compressing it around the smaller diameter pipes didn't seem to make a great difference as the insulation was so thick anyhow. Around the 3" header piping compressing wasn't an issue apart from the bends. I'm sure it isn't perfect, but keeping a little bit of heat in the basement isn't all bad... and it still beats the bare pipe by a mile.

Gilbert Buras

EDR and sizing boiler to radiators

Having been flooded out of my house with the brand new Amercan Standard 90 furnace, I moved into the old family house with steam heat and found a cracked vessel in the 1926 Ideal Redflash boiler. Got a whirlwind education on this forum. This is a single pipe system with nine radiators (originally eight)on a single floor with the condensate flowing in the same direction as steam. How do I determine the "EDR" (what does that stand for?) or the size of the radiators to match them to the right sized boiler? The house is approx 1800 sqft with 12 ft ceilings. There are not many residential steam systems in New Orleans and I want to know what questions to ask the contractors.

Bob W._3

Go here to get an idea of each Radiator's size, which is measure in sq. ft. EDR.

http://www.burnham.com/Sizing.cfm

Add them all up and then post the results and others here will help you along.

ja_2

edr

I asked a similar question here on 11/17. The website for calc of edr that I thought was helpful from a homeowner's perspective was www.colonialsupply.com/resources/radiators/htm

ja

Gilbert Buras

Sizing Boiler to Radiators

After posting last night I found the definition of EDR and the Colonial EDR chart.

I have seven 5-tube 23-in. Cortos, one 4-tube 36-in. Corto, and one 23-inch 2-column which was a late addition to the system. Using the Colonial EDR chart I calculated 12,240 for a 5-tube 17-coil, 23-in. Corto and for all radiators a total EDR of 91,790 BTU/hr. Does that sound about right for an 1,800 sq. ft house?

This is a single pipe, gravity system, parallel flow. Except for a 10 ft run to the added radiator, supply piping is a total of 86 feet, split evenly past the header into two rectangular runs with an 8.25" drop over 43 ft run. No insulation except on the 45 degree drops from the radiators. Looks like all radiators have the original American Radiator air vents (and I remember some of them spitting water and steam even 40 years ago).

What factor do I add for piping? And what should I use for pipe insulation? I wouldn't be doing this myself if It were possible to get a plumber in anything less than 6 weeks down here. It's a nightmare.

A million thanks for this forum.

Ryan_9

Insulation

I'm sure someone will think this is ridiculous and stupid, but I just used standard R-13 Owen's Corning PINK insulation from Lowe's about 1-2" thick and wrapped with 250* "pressure sensitive" metallic duct tape, also from Lowe's. Where possible, I even left the Kraft paper on the stuff. On less than a 2" pipe, you'd have to pull it apart and get itchy and have some fun. Total cost about $.40 per foot, but time consuming.

You can get prefab stuff that is fast, simple and easy to do for about $3.00 to $4.00 per foot. It's your money, time, and itchiness. $400 vs. $40 wasn't much of a debate for me.

Mike T., Swampeast MO

Neither ridiculous nor stupid. Just rather difficult to avoid compressing the insulation when you install. When compressed, the insulation value of fiberglass is greatly reduced.