single pipe steam boiler 2

[DaleDe]

In a single pipe steam boiler system how important is the steam valve on the radiator. If the valve was removed from the radiator and plugged would the rad still heat up, if so to what degree. The system runs at 2 or 3lbs.

DaleDe

 

[StoneCold]

DaleD
Are you talking about pugging the vent on the condenser (radiator)?

 

[MintJulep]

Assuming that you are refering to the air vent, it is important.

If the vent is plugged there is not way for air to exit the radiator as steam tries to enter, hence no heat.

 

[TBP]

You also need the vent to open when the boiler cycles off, so the vacuum will be broken when the steam in the rad condenses. This lets the condensate drain back to the boiler. Steam systems like this need to "breathe".

 

[DaleDe]

I realize that the steam would be blocked if there wasn't a way for the air to escape. When the pressure of the air, as the steam pressed apon it, match the pressure of the steam, the steam would not be able to go any further into the rad. Would it be correct to say that you may get 10%, 20% or 30% of the bottom of the rad warm. The rad would never realize it's full potential because the trapped air would have no place to vent.
DaleDe

 

[TBP]

Trapped air will act like just a spring. Proper venting on a one-pipe steam system is absolutely critical. Each rad needs to be correctly vented, and so do the mains. If you want to have a really good explanation of how these systems work, and what to do if they aren't working, go to

http://www.heatinghelp.com

and consider buying "The Lost Art Of Steam Heating". It's got pretty much all of the old systems in there, and most of them can be made to work properly and efficiently for a fraction of the cost of tearing them out, and replacing them with hot water or forced air.

 

[MintJulep]

The vent doesn't vent only the radiator, it also vents the piping leading to that radiator. So, there is no rule of thumb about how much heat you may or may not get from a specific radiator with a plugged vent. If it is a short run back to the boiler you might get a little heat.


If you are really courious about a particular radiator, plug the vent and try it. It won't hurt anything.

 

[chicopee]

It seems to me that having a low pressure steam heating system "breathe" between shut down and start cycles would be deleterious to steel and cast iron in the piping and boiler due to carbonic acid. Any time oxygen is introduced in the steam and its condensate you are creating more carbonic acid. In addition if a Hartford loop is incorporated in the boiler, steam would be forced up the steam header and distribute itself throughout the entire heating system and return as condensate back to the boiler thru a segment of the hartford loop. So, are the vents really designed to reintroduce air back into the system to prevent the possibility of creating a negative pressure,but increasing the concentration of carbonic acid once firing stops, or would the internal pressure go back to atmospheric (nearly void of air) which is where the internal pressure started before firing? INPUT GREATLY APPRECIATED.

 

[TBP]

You need to remember that these systems typically didn't have any pumps in them. The condensate drained back directly into the boiler, via the Hartford Loop. This gravity return design is why these old system only ran at 2 PSIG max. (Some only ran on inches of water column pressure, others were vacuum systems.) The 2# operating pressure meant that the condensate only had to "stack up" in the return piping about 5 feet, before it could start to drain back into a running boiler. This is why many of these old installation had boilers that were installed in pits, below the elevation of the basement floors. At the end of the firing cycle, the vents need to admit air, so the the condensate can drain properly.

The book I mentioned in a previous post "The Lost Art Of Steam Heating" describes all of these old systems (and there were many designs) far better than I ever could. And it's written by a guy who can tell an amusing story, so it's not like reading the phone book. Some of these systems were amazingly simple, yet worked flawlessly. Others incorporated very sophisticated controls - like one that sense the draft up the chimney, and throttled air dampers to keep the coal fire going all night. And it was ALL mechanical - no electrical components at all. There were some truely gifted people designing mechanical systems 100 years ago.

 

[TBP]

Here's a link to a string that's currently running on heatinghelp.com . It's specifically about an old "Broomell" steam system. My background is almost entirely industrial & utility steam systems, and I've found that there are a LOT of spins on these old low pressure systems that are just...different than what I'm used to. I've discovered that you can't necessarily just "drop in" knowledge & experience from newer, higher pressure systems, and have it apply very well. There are people (mostly contractors) posting on that site who can run rings around me on these old steam heating systems. "Steamhead" is one of them.

http://forums.invision.net/Thread.cfm?CFApp=2&Thread_ID=23761&mc=5

 

[MintJulep]

Chicopee,

Right, pressure drops back to atmospheric. In the off fire cycle the air vents don't forcibly introduce air, they just prevent a vacuum from forming.