Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Two pipe steam questions

(I originally posted this on the main forum, and was advised to re-post here).


My wife and I recently bought a house with steam heat, and I have some questions I was hoping someone could help with. Mainly, I would like some help identifying the system so I know what I'm looking for and how to maintain it. Our boiler is only about six years old, but the radiators look like they haven't seen any maintenance in decades. About half of them have leaky inlet valves.

The house is in Philadelphia, built in 1912. All the radiators say "Union Radiator Co. Johnstown PA". The return elbows have a "B" on them. I've attached some pictures of the boiler area and a few of the radiators. There are a couple things that seem strange to me about the set up. I've read a lot about steam traps, but I don't see anything on any of the radiators that looks like a steam trap. The return side has what appears to be a regular elbow. Is it possible that there's some kind of trap in that elbow, or in the nipple? Or is it possible that the system doesn't have traps? Another strange thing is that one (and only one) of the radiators has an air vent on it (picture attached). I thought two-pipe systems generally didn't have air vents. Finally, in the basement at the very back of the house, the steam main (or header?) is connected to the return pipe with a loop that dips down from the ceiling of the basement all the way to the floor. There are a couple pictures attached that show the loop. This is the farthest point in the basement from the boiler, where the last risers go up.

When we first turned the heat on a few days ago, the pressure was set to 5 PSI. It's a honeywell "Cut-in" pressuretrol. After reading a lot of things about steam heat, I found out that lower is generally better. I turned it all the way down to 1/2 PSI, and all the radiators get hot. It takes a few cycles of the boiler for the farthest radiator to get hot, but it eventually does.

As I mentioned, about half the radiators have leaky inlet valves. I would like to replace them, and I'm considering doing that myself. As you can probably guess, I've never messed with steam heat before. However, if it's as simple as unscrewing the old valves and screwing the new ones on, I think I can probably handle that. However, I'm also wondering what else I should do to properly maintain the system. In addition to the leaky valves, we also have some water hammer (not every cycle, but sometimes). Does anyone know if my system has steam traps? If so, I'm not sure how to identify them, and if not, would it be wise to add them? Is adding steam traps a reasonable job for an amateur, or is that something I should hire someone to do?

None of the pipes are insulated, so I'm thinking about insulating them at least where they're accessible. I'm hoping that might reduce condensate in the supply lines and cut down on the noise.

Sorry for the long post! I hope someone can tell me a little bit about the system. By the way, I have ordered a copy of "We Got Steam Heat".




  • crash2009
    crash2009 Member Posts: 1,484
    edited November 2012
    Kriebel System?

    Just a wild guess.  Does the "B" on return elbow stand for baffle? 

    Page 260 The Lost Art of Steam Heating
  • JStar
    JStar Member Posts: 2,752

    Those elbows are definitely some type of trap, like crash mentioned. Are there any markings or names in the original hand valves?

    I also see an air vent on one of the radiators. That doesn't belong there on this type of system.

    That long loop at the end of the main is a water seal, so that a trap isn't required.
  • JStar
    JStar Member Posts: 2,752

    Here is some info for the Kriebel system.

  • Steamhead
    Steamhead Member Posts: 16,736
    edited November 2012
    Not a Kriebel

    it's some sort of Orifice Vapor system, possibly a Tudor variant from the looks of that loop seal. The B in the circle is actually OB, which stands for Ohio Brass, known for making radiator valves and return elbows.

    I've seen those radiator shutoff valves somewhere but can't remember the brand. What name or trademark is on them?
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • MikeDeLaurentis
    MikeDeLaurentis Member Posts: 11
    Valve markings

    Thanks everyone!

    There are no markings (that I can see) on the valves themselves. One of the valves has a washer on the screw that holds the (now deteriorated) wooden handle on, which says "ADSCO 55". That's the only marking I can make out on any of the valves.

    I guess my priorities right now should be to get the pressuretrol replaced with a vaporstat so I can get the pressure as low as possible, and to replace the leaking valves. Does anyone know if those valves can just be replaced with modern ones, or if there is some particular kind of valve that needs to be used? Based on what I've read it seems like the "orifice" is a small hole on a disc between the valve and the radiator, is that correct?

    Anyway, thanks again.
  • crash2009
    crash2009 Member Posts: 1,484
    american district steam co

    Regis, I'd like to change my guess to The ADSCO system.  Page 261 TLAOSH.

    Mike, any other odd looking devices hanging from the ceiling?  Does one of the steam pipes go into the chimney?  Do you still have the cylindrical condensate receiver?
  • MikeDeLaurentis
    MikeDeLaurentis Member Posts: 11
    No other devices in the basement

    There are no other devices hanging from the ceiling, and really no other devices at all connected to the system in the basement. I don't see anything that looks like it could be a cylindrical condensate receiver. Just the boiler, the auto filler, and the pipes, including that loop hanging down from the ceiling.

    None of the steam pipes go into the chimney, at least not in the basement.

    Like I said, I ordered a copy of "We Got Steam Heat", which should be hear in a couple days, but it sounds like "The Lost Art Of Steam Heating" would be a good purchase too.
  • Rod
    Rod Posts: 2,067

    Both "We Got Steam Heat!" and "The Lost Art of Steam Heating" are great books. You want to read "We got..." first as it gives you a good grounding in the terminology and basics. The LAOSH goes into it more in deal. I read them the other way around which was much harder, sort of like taking a trigonometry class before taking geometry and algebra!

    - Rod
  • MikeDeLaurentis
    MikeDeLaurentis Member Posts: 11
    A few updates

    I had a plumber come out and look at the system this morning. He's located right in our area, and familiar with steam heat, but admitted he was a bit confused by our setup. He said he's only seen one other one like it. I was hoping I could get some feedback on his ideas, and see if anyone has any other suggestions.

    We noticed that the water hammer seems to be originating mostly in the basement, at the back of the house, near where a couple risers go up to the upper floors. This is right by the spot where the supply and return mains are connected with that loop that dips down to the basement floor. (Is that called a drip loop?) This loop is included in a couple pictures in the original post. He theorized that this loop might be clogged, allowing condensate to back up into the supply main, causing the water hammer. Interestingly, we have two mains, one leaving the boiler and heading towards the back of the house, and another one heading to the front. We only seem to get water hammer in the rear main. At least, we only tend to hear the noises in the rooms in the back of the house.

    As I mentioned before, there are no vents that I can see, other than on one of the radiators. I don't see anything in the basement that looks like it could be a vent. That seemed odd to both me and the contractor. Is it possible that there are vents hidden in the walls or below the roof or something like that? Are those packless valves actually supposed to vent air also?

    Anyway, his ideas were:

    1. Replace the leaky (packless) supply valves with new ones. He's not sure whether they can be replaced with ordinary valves, and said he'd ask around about that. I'm guessing based on what I've read here that they're orificing valves, and will need to be replaced with similar devices.

    2. Take apart and rebuild (with new black pipe) the loop that drops down to the basement floor connecting the supply and return mains.

    3. Add air vents in the basement near the spot with the loop, one vent for the supply and one for the return.

    I forgot to ask him about replacing the pressuretrol with a vaporstat, but I'll ask him about that if we decide to move forward with these other things.

    Do those seem like reasonable things to do? If not, can anyone recommend a contractor in the Philadelphia area? I tried the "Find A Contractor" search, but I actually don't come up with anyone within 10 miles of my zip code (19143), which seems odd.
  • packless valves

    if you can get your pressure down to a couple of ounces, with a vaporstat, the valves may not leak any more.--nbc
  • MikeDeLaurentis
    MikeDeLaurentis Member Posts: 11
    Following up

    I had someone rebuild the drip loop (I think that's what it's called), which connects one of the steam mains to the return in the back of the basement. That did wonders for the water hammer. It still bangs occasionally, but probably only about 5% or 10% of what it was doing before.

    I think we may end up replacing the boiler in the summer. Apparently the near boiler piping is wrong in a few different ways, and depending on how much it costs to re-pipe it I might just want to swap out the boiler for a gas one anyway. Not looking forward to that expense...

    Anyway, thanks for all the advice. I have a few more questions about the valves, which I'll post in a new thread.
  • BobC
    BobC Member Posts: 5,473

    That boiler should have a lot of life lest in it but it does have to be repiped in threaded steel per the manufacturers piping diagram. What make and model boiler is that, you might be able to put in a Carlin EZgas burner that would save you the cost of a new boiler. It will still cost but it should be less expensive then a new boiler install.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • MikeDeLaurentis
    MikeDeLaurentis Member Posts: 11
    Boiler model number

    It's a Weil McLain, model number P-SGO-5, series 3.

    That's a good point about the gas conversion kit. If the boiler's still in ok shape after this season maybe I'll go for that.
  • RJ_4
    RJ_4 Member Posts: 484

    Recommend changing all piping on and near boiler to black (carbon steel ) pipe with cast iron fittings and swing joints.
This discussion has been closed.