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An old and ignored steam system

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It's been quite a while since I was up to my elbows in steam. We got a call the other day from a community outreach organization. They have a converted church and attached building made into offices and residences. They were having heating issues. It is a two pipe system with about 30 radiators, some are baseboard type. All have vents on them. There is even a radiator with a main at the end of a 5' nipple piped between the radiator and the trap. It is very hard to trace, but it appears all but two or the returns have main vents. None of the piping in the boiler room is insulated. We were told that they flush the LWC every week, but the water came out like chocolate.
To top it off the pressuretrols are piped wrong so the pipe leading to them was plugged solid and there were no pig tails.
What I want to do is replace the pressuretrols and repipe them, insulate the supplies, add mains, and teach them how to blow the boiler and returns down. My questions is should I remove all the radiator vents? Most of the traps, and I assume they exist, are buried in the floors with no access. If I pull out all the vents and it stops working I may end up living there. I've been told if it ain't broke don't fix it.

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  • Dale
    Dale Member Posts: 1,317
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    Glad it's not me

    Boy I'm glad I didn't get this call, and not just cuz it almost Christmass. I guess the thing to do is write the job up in steps to get paid after each step. How does the near boiler piping look? How much wet return? I was going to say first thing is to make it safe but I hate to waste money on a bandaid that they won't feel ( heat) So,sure a make it safe price, with 2 pressuretrols you're over 400K input, backup low water cut off? Auto fill working. Then a near boiler piping price with insulation, and vents and traps and as much flushing as possible. then the rads and other traps. Good luck man.
  • john_27
    john_27 Member Posts: 195
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    chocolate water ...

    can be caused by a high water line....check the level...make sure the Mcdonnel Miller is piped correctly...also...before you price or do work...get the name of the system(sounds like it is a vapor system)...post pix...and we'll get to work
  • Steamhead
    Steamhead Member Posts: 16,842
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    Since this is a two-pipe (probably Vapor) system

    there has to be a way of keeping the steam out of the dry return. This can be done with traps, water seal or check valves on the return connections, or orifices at the radiator supply connections. The vents on the radiators should not be needed.

    Try to find some radiators that have all original fittings on them. See if there are any manufacturer's names on these old fittings (valves, traps etc). Also look for Vapor hardware in the piping around the boiler. This will help us identify the system. And take plenty of pics!



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  • Paul Fredricks
    Paul Fredricks Member Posts: 7
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    Thanks. I'll check

    out all these things and try to get some pictures today. Check valves were installed a couple of years ago. I think the water level is OK, but I'll recheck. My guess is that the dirty water is just a dirty boiler. There are blow down valves on the return, but not on the boiler itself. Just a small boiler drain that I do not dare to try unless I replace it. I'll try to post pictures later today.
  • Keith_8
    Keith_8 Member Posts: 399
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    Filthy water

    Are you able to see all of the returns or do some of them disapear below a slab or under a crawl space? If there is a undetected condensate leak you could be taking on an excessive amount of make up water causing excessive corrosion.

    If it is a vapor system your going to want to swap out the pressuretrols for vaporstats and get the system to operate in ounces and not pounds.

    Some vapor systems use the inlet valve as a metering devise to control the amount of steam entering the radiators. They only allow enough steam to enter the radiator as it is able to condense so the steam is unable to enter the returns.

    Sounds like you are on the right track with customer relations. If you are able to communicate to them the benefits a properly maintained and functioning steam system the repairs will pay for themselves in short order.

    Good Luck,
    Keith
  • Paul Fredricks
    Paul Fredricks Member Posts: 7
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    Here are some photo's

    Things to note. The picture of the radiator is typical of most. Two lower pipes, an air vent, no sign of a trap and no access under the floor that I could find. The picture of the straight radiator with a main vent piped between the rad and the trap is interesting, but not sure why it is like this. There is a photo of a 2" and a 1" line disappearing into the wall. These are returns with no main vent that I could find. The pipe above is a supply. The return behind it has a main vent. The supply out of the boiler has an equilizer piped over to the loop and the supply feeds three motorized valves. Check out how the pressuretrols are piped. This will be corrected shortly. There are check valves in the returns. Any thoughts on this set up?

    Paul
  • Steamhead
    Steamhead Member Posts: 16,842
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    This is a 2-pipe air-vent system

    The radiator has shutoffs on both the supply and the return, and an air vent. That cast-iron beauty is called a "flue" radiator, for those of you who have never seen one. On this system the dry returns are NOT vented. If you vent them, steam will enter them and cause banging.

    The Pressuretrol piping is actually correct. It doesn't use standard pigtails, but the drop elbow allows water to sit in the horizontal pipe which does the same thing as a pigtail. The only thing I'd suggest is, if the installation requires CESD-2 redundant controls, move one of the pressuretrols to a different tapping in the boiler. Better yet, replace it with a Vaporstat. This system should run on less than a pound, to help keep steam out of the dry return.

    The fin-tube installation does look kind of strange. The trap is not needed here, but you do need the vent, assuming it's piped into the same dry returns as the old cast-iron rads.

    The motorized valves may cause water to back up into the returns when they're off, since they cut off the "leftover" steam pressure in the main. Running lower pressures will help, but if I were working on that system and the boiler needed replacing, I'd use three smaller boilers and separate the piping so each zone is independent.

    This system will run great when you finish with it.

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  • Paul Fredricks
    Paul Fredricks Member Posts: 7
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    OK, what you are saying is...

    I should remove all the main vents that are on the returns and lower the pressure with a vapor stat. The drop elbow set up was plugged and had to be punched out. That's why I wanted to repipe it. Should I change this to a set up with pigtails? And what about the existing traps. Do they need to come out? Or will they not effect the operation of the system if they stay in. There is also fin tube in the old sanctuary area that has vents and traps. I believe the boiler is only about 10 years old so changing it is not in the cards.

    Paul
  • Steamhead
    Steamhead Member Posts: 16,842
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    Check to see

    what type of radiation is connected to which return. This may take some doing but is worth it.

    The 2-pipe air-vent rads should go into a return that is NOT vented.

    The rads with traps are OK if they go into a return that IS vented, as long as the ONLY radiation connected to such a return has traps. If this is the case, the vents on the radiation with traps are not needed. If the return has both types of radiation, remove the traps, leave the rad vents in place and don't vent the return.

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  • Paul Fredricks
    Paul Fredricks Member Posts: 7
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    This could be fun

    The returns head off in directions you never would expect given the lay out of the building. As they leave the boiler room they are lost behind walls and everything else due to 100 years of remodeling. I'm going to insulate and add a vaporstat, then see what happens. As I said it does work now, just not always well. This place is non profit and can't afford the time for me to toy with the set up.

    Happy New Year everyone!!

    Paul
  • Steamhead
    Steamhead Member Posts: 16,842
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    If you can't see the returns

    and they're still having problems, just make everything the same- vents on radiators, no traps, no vents on returns. And a Vaporstat to keep the pressure low.

    Let us know how you make out.

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