question

Ken_8

with regard to steam, it is very rare and completely wrong to have radiators hooked up in series. Each rad should have it's own riser & feed off the main, and the main should always be vented (of air). The size of the main(s) air vent(s) is generally summed up by using one that is as large (in the amount of air it can pass - not necessarily physical size) as possible.

Balancing the mains is not a high priority. As long as each is properly vented they will all vent within a minute or two of each other. The radiator vents however are another thing. By using various sizes of vent orifices, one can adjust individual room comfort and temperature by simply changing vent sizing.

You may want to go to the Gorton Valve website. That's my first choice in both steam and rad vents. A few others are as good. Stay away from the 8-dollar "wonders" at Home Depot. They are noisy, poorly made and come in the one-size-fits-all mode.

<A HREF="http://www.heatinghelp.com/getListed.cfm?id=68&Step=30">To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"</A>

BostonGC

Balance

Does it make a difference in how the load is applied on a steam main?

For example, would it matter if the raidators were piped in parrallel or series? Seems like they are usually piped in series, which surprises me intuitively seems piping in parrallel would get more steam up faster.

Also, can someone explain how the mains are balanced in a system? It seems that all the mains should be designed to have nearly the same load, but I am not sure that I ever heard this discussed as a rule. Or if things are not balanced, what would happen? Cold rads?

BostonGC

all would have risers.....



Ken:

Thanks for the info.

I probably did not explain myself clearly. I understand all rads should be on their own riser off the main, my question meant to ask, does it matter if the main "branches" off so as to have each of say 3 rads on their own leg of the main, or is it better to have one main really long to supply all the rads. Or does it not matter as longs as the venting is adjusted(as your post clearly explains)

Putting it another way, how do you decide when to use an additional main from the boiler - why not just use one and branch off from that to hit all the rads in the house. Or why not put each rad on its own "main" from the boiler(forgetting about piping issues, would this perform better?).....if you were going to design a system from scratch I wonder how these decisions were made(dead men?).

Just thinking.

BostonGC

I think this answers my question

From one of Dan's books:

(Apparently, it is better to have multiple short runs to the rads if you are not using coal! I guess if I were designing a new Steam System, you want a managable amount of fairly short mains to service your load. Compromise of load/piping considerations)

The Dead Men piped the system for a coal burner.
In the days of coal-fired steam boilers the coal pile would burn all day, nudging the steam gently through the pipes and toward the radiators. Knowing that the firing cycle would last at least eight hours and never cycle on and off, the Dead Men often used long perimeter mains to carry the steam from the boiler to the radiators. The main typically followed the foundation wall and dropped below the boiler water line only when it was done wrapping its way around to the basement. From the main, they ran relatively short takeoffs to the radiators.
As oil- and gas-fired systems grew in popularity, the Dead Men faced a problem. Unlike the coal-fired boilers, these new burners cycled on and off. The thermostat often shut off the burner before the steam reached the end of that long main.
To solve their problem, the Dead Men began to pipe their jobs differently. Rather than use a single long main with short takeoffs to the radiators, they used several mains, each heading in a different direction. With these shorter mains, the runs to the radiators usually had to be longer. But that didn't present much of a problem as long as the Dead Men dripped and pitched their lines properly.
If you find yourself facing one of those old, coal-fired piping arrangements, put as many air vents as you can near the end of the main. Your goal is to get the air out of the main quickly so the steam favors that route. If you can fill the main with steam as though it were a long heating trough, you'll do a much better job of balancing the heat throughout the building.