2 pipe steam system -- Mix of vented and unvented radiators

dkflyer

Gentlemen -

1920s-built house, I have a 2 pipe steam system. Last month it looks like I burned about 260 gallons of oil on the dot.

The home has three floors, plus a basement.

So, what happened it looks like over time some of the original radiators were removed and recessed into the wall. As a consequence, some rooms feel underheated - this is my main issue. The rooms that are underheated have newer recessed into the wall radiators. Some have air vents on them. The original radiators do not have any air events on them.

When I moved into the house, I had a contractor remodel two of the bathrooms - one on the second floor and one on the third floor. Part of the job involved recessing the then current radiators in the baths that were taking up excessive space. However, he put an air vent on the recessed two-pipe radiator - and as a consequence, a tremendous amount of clanging occurs on the third floor bath, but not the second floor. Interestingly enough, the radiator does heat well.

So to recap, original radiators - no air vents, new radiators - air vents. Should I remove the air vents? Somehow add air vents to all? I don't know how the original design had air escaping, perhaps I'm not seeing it. I noticed that the return line in the basement has a pressure vent, looks pretty old. Otherwise the pipes look sealed all the way back to the boiler to me.

I am looking to get this system operating more efficiently and heating more.

dkflyer

New recessed radiator, contractor installed. I have two of these total.

Original Radiator. We have 6 of these total.

dkflyer

Radiators that the previous home owner had installed. We have one of these without the air relief valve depicted, and three with them.

JUGHNE

We need to see more detail of the valve on the original radiator shown. Brand name on handle, what does the hang down indicator point to? The small pipe on the bottom, are there any brand names on that.
In the basement below can you show us where the small pipe connects.

And pictures of the boiler showing all piping floor to ceiling, especially the small piping that return to the boiler.

KC_Jones

It's not really as simple as should you remove the vents. The piping is what matters here.

I looking at the one original radiator, I don't see a trap, so really the first thing here is you would need to identify what system this is. Is it orificed? I can't remember the name, but one system oversized all the rads so steam would never get to the return. Are the traps in the basement? All this needs answered before recommendations can be made, and honestly, before those contractors touched anything.

As far as the banging, that's a slope/water issue. Water is laying somewhere in the piping and banging. It's usually because of improper slope, or a sag in the piping. So your contractor may have messed up the new piping...

Also 2 pipe should be run at very low pressure. Do you know what the settings are?

I am not a 2 pipe expert so others will chime in with more information and probably more questions.

It wouldn't be a bad idea to post pics of any changed piping, the boiler piping, and the pressurtrol settings.

dkflyer

dkflyer

Thanks for your comments.  The hanging tab on the Hoffman specialty handle does point to a setting printed on the valve itself - so it reads relative position (I didn't notice that before!).

Jamie Hall

Well, once upon a time it was a vapour system -- which means basically that it was designed to run at very low pressure (less than half a pound per square inch) and, most likely, the valves on the radiators were set so that the radiator almost, but not quite, managed to fill at that pressure.

However, it is also very likely that it has been "altered" over time, which is almost never a good thing.

It would be most helpful to know how the steam mains are arranged, and to what the outlet -- low -- pipes from the radiators connect, and how that then gets back to the boiler.

Originally there would have been just the vent you mention in the basement. Air and condensate would have left the radiators by the small outlet pipe and would have gone to a dry return, which would have gone back to the boiler, near which that vent would have been located. There may also be wet returns, depending on the direction the steam main or mains slope, and there may have been an arrangement for air to escape from the steam main into the dry returns, called a crossover trap.

But we need to see a lot more of the piping -- and a good diagram, if that is possible -- to see what of that is left and how to reconfigure it.

Those recessed radiators can heat, but often not as well as one would like. Depending on how the outlets from them are piped, they may or may not need the vents. We need more information on that, too.

veteransteamhvac

I have a 2 pipe low pressure vapor steam system with extremely similar radiator valves and similar near radiator piping with no orifices or traps. I have vents on almost all of my radiators from original installation. I have one main vent located at the end of the dry return.

I have 2 radiators in the living room that were recessed at some later time. My experience is also that they heat poorly and I am in the process of returning them to their original location.

I have had banging issues that were due to sagging pipes, especially on the relocated, recessed radiators.

dkflyer

Basically a large main goes across the center of the house, then branches out in two directions around the circumference of the house. At that point, there's the feed line and the return line running in parallel. There are no traps, vents on those lines until it wraps around all the away back to the boiler, prior to the drop back into the boiler. That's where those Gorton Air Eliminators are located - one for each branch coming around. Pipes for the first floor are fed directly, pipes for the 2nd and third are all located on the perimeter (I wonder how much loss is occurring just for that reason).

Fizz

Prior house I owned was grandparents built in late teens; had Richardson system which may have been your system as one of rads has Rich valve and return rad pipe has no trap, rather an elbow(el) as did mine...in the el is an oriface to allow for water draining from steam; there should be a small ball in the el that lifts to release return water and sets to stop air from enetering or steam from getting into return. Very simple yet effective system requiring no maintenance unless ball needs to be cleaned(rare) or sticks...which did on 2 of mine-a quick rap at elbow with a shoe heel or rubber mallet worked for me . Mine over 100 yrs still working no traps in orig rads.
There were 2 rooms added in the 20's wit 2 rads in one(kitchen) and 1 in bath, which had traps, and air vents added in 60's when oil replaced coal. They didn't heat well, so i removed them and repaired vents, problem solved.

dkflyer

So what I've been trying to figure out is whether there is a trap on the return.  It looks like a standard elbow to me, no ball nothing.  If there is a ball, I'd be surprised.  In terms of efficiency, I'm worried about the returns on these 100 year old radiators.  Should I attempt to loosen the nuts and check for any blockages on the returns, or is that not typically an issue?

Also, should I remove the vents??  On the radiators with adjustable vents, I actually just set those to close.  So the air would have to go down the other side.  I'm just not sure how that's a good idea but I want it to work the way it originally was designed.  Option 2 would be to replace the fixed air vents with the same kind of adjustable vents, experimenting with "closing" the vent.  Radiators still are heating.

Also, I've become obsessed with the idea of creating a vacuum in the system. If the system is hermetically sealed then I could envision a vacuum pump that actuates upon a call for heat.  Anyone have any suggestions there?

Finally, I did my calculations in terms of annual fuel burn.  My home is 2600 sqft and three floors.  It's burning 1,700 gallons of oil a year.  Is this excessive? Part of the problem is that hot water is indirect to the boiler.  What would you all suggest I do to make the system more efficient? I do, oddly, have a sufficient gas line into the house that just powers the stove at the moment.  The hot water tank looks like it's on its last legs, I see corrosion on some pipes and I will need to replace it in the next two years.  I live in Westchester county which has a moratorium on increasing gas load until 2022, so any gas conversion will have to wait, but I would like to know what my best option is here.

Fizz

If it's a Richardson sysem,those els definitely have a ball...if your curiosity gets the better of you, you can check by loosening nut to expose el...but be careful not to damage or lose ball. On this site, check archives for antique systems, look for Richardson it'll show the important parts ofsystem,including el. As for checking for blockage on return, that's a question for the more knowledgeable individuals on this forum. As for removing vents on rads, I did, but you could invert vents to see if system works, then remove and plug. I turned my system into vacuum by replacing main vents with Mepco Quick vents which are vacuum... I was lucky, as at the original main traps were long gone. The system worked great, I also replaced thermostat with honeywell round mechanical and used setting for hot water, instead of steam. System worked perfect, and current owners haven't had to add water in the 2+ yrs they've been there.

veteransteamhvac

The very first thing I would do is get a 0-5lb pressure guage and also vaporstat. Your system looks so much like mine that I think these things will help you. If you're very into figuring it out you will have to take a valve apart and show pictures of what they look like inside. I suspect they look like mine with variable orifice sizes, nothing on the return side.

Since the proper operation of our systems requires vents at the radiators you don't have to begin thinking about vacuums and such. Operating at too high pressure might be affecting your efficiency. Have you done any calculations to see if the boiler is right sized? Maybe a combustion analysis would be useful?

dkflyer

Under a vapor static system, should vents be installed on all radiators? Original radiators only have the thermostatic control, I don't know if it is also a vent, some of them I notice did let air pass. With the heating season over, I'll be more inclined to tinker. I think the radiator that is recessed on the second floor that is without a vent is not heating as well as it should.

Jamie Hall

As I mentioned earlier, this was -- once upon a time -- a vapour steam system. That is, it operated on very low pressure -- a few ounces, no more, per square inch, and vapour delivery to the radiators was controlled by valves like the one you pictured.

Those valves, by the way, are not thermostatic, although they can be partly closed if desired to reduce the heat from a radiator.

Air and water would have been released through the return pipe and would have gone into a dry return, in the strict sense of the term, running near the overhead in the basement (often parallel to the steam main). The outlet may or may not have been controlled by a trap or other dev ice, or may have simply depended on the correct setting of the inlet valve and maintaining very low pressure.

The dry returns would have been vented at or near the boiler.

A very simple system.

If it hasn't been too badly messed up, it can be restored to that simple system. The vents you have on some of the radiators tell me that it has, indeed, been messed up. They don't belong there. But it is quite likely that they were added at some point to compensate for some other knuckleheading.

What is needed is -- as someone once put it -- to put your hands firmly in your pockets and to go through the system from the boiler to the ends and ask yourself "how was steam supposed to get into that radiator? How was condensate supposed to get out and return to the boiler? And what was supposed to happen to the are?" Then make a nice diagram of it and figure out how it got messed up and restore it.

Don't start fiddling with things until you understand how it was supposed to work in the first place.

ethicalpaul

I love reading your descriptions of these vapor systems, @Jamie Hall. Slowly my understanding builds every time I read one of them. Do the vents on the radiators hurt the system?

Jamie Hall

ethicalpaul said:

I love reading your descriptions of these vapor systems, @Jamie Hall. Slowly my understanding builds every time I read one of them. Do the vents on the radiators hurt the system?

Not really. It depends on what, if any, of the hardware the system had on it to control overpressure. If that's still present, and you want them to work, the radiator vents (or, for that matter, extra vets out on the mains) will defeat it and they've got to go. Otherwise... no, not much. They just hurt the purist in me!