Two pipe heat and excessive banging

Steamhead

and I think you've isolated the cause of the banging. In this type of system there is not supposed to be any connection between the steam and return pipes without a device like a trap, water seal or orifice to let air and water pass, but keep steam from entering the return.

With a direct connection (the "Loop") between the steam and return pipes, steam rushes up the returns to the upstairs radiators, looking for the vents on them. That loop should be repiped so it drops at least 3 feet (more if you can do so) then rises back to the dry (overhead) return. This way it will fill with water and the steam will not pass thru it.

The vents on those radiators don't belong there. Air should pass from the radiators into the dry returns, and out thru that vent in the boiler room. The piping around that vent is correct as you describe it.

The vent on the steam main is probably bad- hammered to death from the banging. The trap between the steam main and the dry return also acts as a vent, discharging into the dry return. It too was probably destroyed by all that banging.

Yes, you should insulate those steam pipes- it will lower your fuel bills as well.

Try to locate any manufacturer's names on the radiator valves, return fittings etc. This will help us identify your system, especially when it comes to the apparent lack of traps on the radiators. And post some pictures here if you can- we love this old stuff!

Where are you located? I'm sure one of us is nearby- try the Find a Contractor page of this site to locate someone who can help you straighten this old beauty out.

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Frank Weigert

I bought an old house build in the 1920's earlier this year. The house was converted from public steam to a boiler in the 70's. The boiler has been replaced in the late 90's. Whenever the system heats it will start to bang excessively. In trying to identify the problem I found a couple of things that I would like to get some clarification on. There are not many people that seem to know steam heat anymore and always everybody has a diferent opinion.

1. When I bought the house the cut in was set to 2 psi. In this setting the banging was absolutely unbearable. I have reduced it to .5 psi, the banging is better and all the radiators in the house still get nice and hot. Any reason why I should not do this?

2. At the end of my basement the furthest away from the boiler the steam pipe will end and makes a 180 degree turn back into the condensate pipe, is that right? Directly before the turn are several feeds away from the steam pipe and directly behind the turn are several returns from my second and third floor back into the condensate pipe. Doesn't that mean that all that steam right after the loop will go straight up the returns ? These vertical pipes seem to cause most of the banging. Right before the loop on the steam side sits a vent that never blows any air, I guess because all the steam is going back into the returns. There is another connection between the steam and condensate pipes with a trap just three feet further down.

3.
In my garage close to the boiler is another steam vent that permanently blows air, this vent actually sits in the the junction where all the returns come back together (there is also a drain line from the steam pipe in this junction). Is this correct ?

4. None of my radiators have traps, I am getting mixed messages wether they should be there or not.

5. Only the last two radiators in the third floor have vents, they seem to work fine. Again all the radiators get hot.

6.Large parts of the piping in the basement are currently not insulated, I knwo that that can also cause banging and I will address that soon.

I know that these are many question at once but I really would appreciate and advice I can get. I am trying to understand this system as much as possible.

Thanks

Frank Weigert

Thanks for your fast reply Steamhead,
I am glad to hear that you agree on the issue with the connection between the two pipes. My radiators are made by American Radiator Co. and the original valves (I replaced most of them because they were leaking) seem to be from a company called ADSCO (I have one picture attached with a valve that still has the original wooden knob on it). I could not find any names on the fittings that still looked original. I made two pictures of the "loop" and also one of the returns with the Air Vent (the boiler is on the other side of the wall) When you look at the pictures of the loop there is invisible on the picture an air vent on top of the steam pipe at the very end right before the turn. The vent and the trap further down are new, I replaced them a couple of weeks ago, the vent however does not release any air.
As you can see on the picture my basement and garage still look pretty scary, it is a big house and the basement was last on my list. But I am sure you guys have seen it all. I also still have quite some of that ugly "white stuff" around my pipes, I haven't decided yet if I want to remove or encapsulate it. I am located in Philly and I have contacted a local contractor from this site to get an onsite opinion. However any additional thought you or anybody else might have would be highly appreciated.

PS: I also added a picture of the original clothes dryer that came with the house. I thought somebody might appreciate that.

Thanks a lot, Frank

[Deleted User]

i agree with steamhead..

that sure looks like a vapor system..disconnect a radiator valve and see if there is an orifice disc installed in it, between the union and valve..also looks like someone hacked into the system, cause the dead guys didn't use copper pipe for steam..look for some sort of name to help us out so we can better help you..names like moline-mouat-oe, etc.. this would really help us. also can we get a closeup picture of some original inlet valves and especially the outlets of the radiators..

Frank Weigert

Gerry,
thanks for your reply. Attached is a picture of one of the old valves and even though I am not 100% sure what an orifice disc is (mind, I am just a "homeowner" ) I think what we see here is one. The returns coming out of the radiators look like regular elbows, I will try to take out a radiator this weekend to have a peek inside. have found two old returns that seem to have a name on the elbow, however it is on the back and I won't be able to see it until I take the radiator out.
The system has definetely been hacked, unfortunately anybody who could know anything about this system has joined the dead men. I know that some of the steam pipes have been replaced by a general contractor, some are galvanized others are copper but that it all he did. I am also sure that there was quite some tampering done when the system was converted frm public steam.

Coming back to the valves, the replacement valves that I installed do not have the orifice disc, how will that affect the system ?

Thanks again,

Frank

[Deleted User]

sorry frank,

i can't tell from the picture if there is a orifice..an orifice is a small hole, say 1/8th or 1/4''...looking thru the valve does the valve have the capacity to pass an object the same size (roughly) as the inlet all the way thru?

Frank Weigert

Gerry,
when you look at the picture you are looking at the opening going towards the radiator. You might see a slot probably 1/8" by 4/8" . This slot is in a disk that sits inside the opening covering the whole outlet, held by a clamp. When the valve is fully opened the slot is the maximum opening for the steam to get into the radiator.

Frank Weigert

Gerry I just measured the opening, the slot is actually only 1/16 by 2/8. Shouldn't trust my eyes when it comes to inches, I am more of a "metric" guy.

Steamhead

ADSCO

stands for the American District Steam Company. They marketed a lot of hardware for public steam systems, and for heating systems used with them.

Frank, if you haven't done so already, get a copy of "The Lost Art of Steam Heating". Your ADSCO Vapor system appears on pages 261-262 of this book. Order it on the Books and More page of this site.

The ADSCO is basically an orifice system, where the radiator valves only open so far to keep steam from getting into the "dry" (overhead) return lines, which can cause banging. Air and water from the radiators passes into the dry return. The air leaves thru a centrally located vent on the dry return, and the water goes back to the boiler. I'll bet your new valves don't have orifices in them, but these can be added.

The key to proper operation of a system like this is VERY LOW PRESSURE. The little gray Pressuretrol on your boiler won't regulate the pressure properly for this system. ADSCO designed their systems so they'd need only a few ounces or pressure, and the only control that can keep it this low is the Vaporstat. You want the Vaporstat model that cannot be set higher than one pound. It's expensive, but is the right part for the job.

I think we have several contractors here on the Wall who are located in or near Philly. But if you have trouble finding one, or if they need some more eyes on that thing, e-mail me. I'm located in Baltimore, but when we're talking steam or Vapor, it's not far at all!

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Frank Weigert

Thank you Steamhead, you truly deserve your nickname. Based on these findings, do yo still recommend to drop the loop back into the return line at the end of my steam pipe,
or is the pressure the only key. Still sounds to me like I should prevent the steam from getting back into the returns through the back door. Also, are the orifices and the low pressure the reason why there are no traps ?
I might take you up on your offer,it seems to be very hard to find somebody who still knows these old systems. Let me look around a bit. I definetely appreciate your help here in this forum.

Frank

Steamhead

You might not need that loop at all

assuming condensate can drain properly by some other means. If you do need it, it should be repiped as described before- and not in copper.

The orifices take the place of traps, even though they're installed on the supply connections. Assuming the pressure doesn't get above 8 ounces or so, they will only admit as much steam as the radiators can condense- thereby keeping steamout of the returns.

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Frank Weigert

I tend to agree. Since the pipe is pitched, how would anything else but steam make it up to that connection anyway ? There is another connection with a trap 2 feet down and the water could also drain back down the steam pipe and then through the drain-connection in the garage (picture in earlier post) into the returns and back into the boiler.
One last question and I promise that's it.
Why exactly is copper bad in a steam system ? The only reason why I am asking is because somebody already replaced many of the old steam pipes and I have probably close to 30 yards of 2 inch copper in my basement.

Thanks again

Steamhead

Copper is bad for steam

because it expands more than steel, and because the soldered joints won't "give" to take up this expansion like threaded joints will. These soldered joints have been known to break apart when used on steam.

However, copper is fine for return lines that do NOT carry any steam.

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Mark Eatherton1

Even then...

I wouldn't use copper. In a steam system oxygen is introduced every time there is shut down.

Copper and steel and oxygne = bad news for lesser noble metals. Anode, cathode...

Steel and good water treatment is the way to go IMHO.

I've seen soldered lines that were running under 200 degrees F get brittle and fail. I've also seen solar lines that were soft soldered fail.

Copper has its applications and steam is not one of them.

ME

Steamhead

ME, do you think

it might be something in the water supply in your area? I haven't seen any such failures here, but all the ones I've worked on were fed from the Baltimore water system.

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Mark Eatherton1

A lot of it...

has to do with time. Some older thicker boilers don't show the stress of disimilar metals for a long time. Some of the newer thinner boilers show it before their time...

Three things are required to set up a good electrolysis battery. Ferrous metals connected directly to copper in an aquaeous solution (oxygen containing water). Just about every steam boiler I know has at least two of the components necessary to set up a good electrical charge.

The water in Denver is actually maintained at an ideal pH and hardness. Its commonly referred to as the Langlier Index. Not too soft, and not too hard. Juuust right;-)

The ratio of degradation is proportional to the amount of copper in relationship to cast or steel product. A little copper won't hurt much. A LOT of copper will.

The temptation to use copper will always be in the back of my mind. If I were replacing a condensate main located below grade, I'd probably use copper with proper isolation. If a person uses yellow brass connections between the copper and other metals, di-electric corrosion is held to a minimum. Let's see, brass valves are generally located between the two metals. HMMmmm...


I will take a picture of the next boiler showing the signs of strong electrolysis the next time I run into one.

ME

Frank Weigert

To all
I want to thank you one more time for all the advice you have given me. I have learned a lot from this thread and actually you have made me curious to learn more. I have ordered "The lost art of Steam" and can't wait to get it.