steam questions

demetre

Hello,

 

I live in a second floor apartment of a 6-story NYC loft building with an old steam system. 

 

The system seems to be a unique 2 pipe type system without traps. 

 

In each loft there is a 2” IPS steel supply riser that tees off to a slant fin steel bare element (typically 2”) that pitches to drain to another 2” IPS steel drain riser.  An air vent is located adjacent to the drain riser.  And a manual shut off valve is located adjacent to the supply riser.  In other apartments there is sometimes a second shutoff riser for some reason located next to the drain riser. 

 

In practice the building is so well insulated with thick masonry and few windows that I rarely have to open the valves to the radiator elements.  However when I do I get a lot of wet steam escaping one of the vents.  I was told that the only thing I can do is attach an extension leg as high as possible (for me would be +/- 6” since the slant fins are enclosed in cabinets) to keep the air vent above the turbulence of the radiator.  Was also told to size the air vent as large as possible. 

 

On my second radiator (fed off a separate set of risers) I have noticed no air escaping and am wondering if it is clogged.  I have noticed that the radiator does not seem to get hot (only slightly warm) and am assuming the air vent being clogged does not pull the steam thru the element. 

 

Any advice on the above would be appreciated.

 

I am also renovating another 2nd story unit in the building and am told to not use any size radiator element below 1-1/4” due to potential water hammer.  I was thinking of using Danfoss thermostatic valves this time and possibly using copper elements in two small bedroom locations where I can only go with 2’ sections.  The copper seems to have the higher BTU rating.  Plumber recommends copper for all locations however noting that the steel corrodes faster.  

 

Any input would be appreciated. 

 

Thanks.

Steamhead

This may be

either an Orifice system, which means the vents don't belong there, or a two-pipe air-vent system in which case they do.



What happens to those return (drain) risers when they get to the basement? Are there air vents on the basement return lines?

Rod

Pictures

Going along with the old adage: "a picture is worth a thousand words", it might be very helpful if you could post some pictures of your radiators showing the piping and the vents as that may help in recognizing what the type of  steam system you have.

- Rod

demetre

pics

Thanks for your replies.

Attached are pics of a sample Slant Fin element and risers. 

I can get access to the basement boiler room if you need me to snap a few pics in there.  Not sure if that would help. 

Charlie from wmass

This is a case of a little knowledge being

a dangerous thing. I can see what they were going for but the condensate will be building up in the return valve and causing banging and hitting the vent with wet steam. The air vent could easily get short circuited from steam back traveling up or down the return.

demetre

thanks

This radiator is actually from another apartment in the building.  I wanted to show an exposed radiator since mine are harder to photograph inside cabinets. 

The tenant tells me everything is fine with his radiators - no wet steam or banging.  But I don't know how sensitive he is to these issues. 

I was told to locate the steam vent as close to the drain riser as possible - are you stating that there should be a clearance between the vent and drain riser to avoid any steam traveling in the return from getting into the vent?

On another note I have been told that the steam vent should not locate on a 45 or elbow fitting (as it is in the photo) as there is more turbulence there. 

nicholas bonham-carter

2-pipe no traps

the way this system would have worked when first installed, would have been to restrict the steam into the original radiators with special inlet valves so that only the amount of steam which could be condensed was admitted. therefore no excess steam would be escaping to the returns. these systems operated with mere ounces of pressure, and were very economical. early energy terrorists [knuckleheads] have disabled these systems one by one, and caused a dramatic increase in heating fuel consumption to our detriment.

now that the system has been "modernised", it no longer works as well as it once did, and probably burns more fuel as well [if anyone has noticed].

my suggestion would be to do the following:

1. make sure that the pressure control [vaporstat] is set for 6 ounces of pressure as a cutout, and maintains that pressure verified with a good low-pressure gauge [gaugestore.com 0-15 ounce]

2.put gorton #2's at the top of each riser, and remove the radiator vents.

3.make sure the return venting is adequate in the basement

4.put orifices in the inlet valves to limit the amount of steam coming in, and remove the exit valves.--nbc

demetre

thanks

Thanks for your advice. 

I was googling two pipe trapless steam systems and found the following article from this website. 

http://www.heatinghelp.com/article/11/Hot-Tech-Tips/280/Two-Pipe-Air-Vent-Steam-Heating

I am wondering if the system outlined in this article is our system.

If so does it really make sense to remove all vents at each radiator in the building except for at the top of the riser? 

Thanks for your help,

Brian