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Is changing this worth the effort?

Powe
Powe Member Posts: 16
I'll try to make this preface as short as possible.
I have a Weil McLain boiler (see sig below for specs) serving a one pipe steam system in a 3 story house. There are two heating loop mains in the basement. I will refer to them as North and South loops. Here's a picture of the near boiler piping:


The North loop is a 1-1/2" main which is actually tapped off the start of the South loop which is a 2-1/2" main.

The South Loop serves ~220 SF EDR, not including pickup factor.
The North Loop serves ~175 SF EDR, not including pickup factor.

I recently added another radiator on the North loop for a room that was served only by a (approx. 12' length of fin tube baseboard radiator on 3/4" copper pipe. I am planning to replace this as it is not original to the house and has never worked very well despite my best efforts.

All of the radiators on the South loop get hot all the way across. None of the radiators on the North loop get hot all the way across.

There are no water hammer issues. The rooms served by the North loop are generally a little cooler than the South loop rooms. The house heat is adequate although the room where I added the radiator still requires supplemental heat from an electric heater. (Note this room is a sunroom with 3 exterior walls all of which have large, good quality windows triple Low-E), and the room is spray foam insulated which provides excellent R value and air and vapour barrier. In other words, the insulation in this room is as good as it can be and is superior to the rest of the house.)

If you look at the near boiler piping in the pic above, here is what I think needs to be done:
  1. The drip leg off the riser is plumbed totally wrong. I doubt if any condensate or suspended water drops in the steam actually drips back in there.
  2. The way the North loop is tee'd off the South loop is also wrong as it will give priority to the South loop.
  3. The pipe size for the North loop (1-1/2) is too small. It was too small to serve the original radiators and my adding another radiator only exacerbated the problem.
My proposal to deal with this:
  1. I would like to redo the near boiler piping to provide a drop header where the two heating loops tee directly off the drop header and the drop header ends at the drip line.
  2. I would like to change the North loop in the basement to at least a 2" main. The charts say that is big enough to serve the EDR on the North loop.
  3. I need to add additional venting on the North loop to accelerate the steam distribution on that North loop.
My concerns (and questions) are:
  1. Will doing all this work be worth it? I am seeing some fairly high heating bills and I think piping has a lot to do with the efficiency (or lack thereof) in the system.
  2. The boiler is about 30 years old, but seems to be in good condition. It was badly plugged up when I bought the house, but I did a lot of work to flush the system and it is working very well now. I flush the boiler weekly, running a few gallons out of the LWCO and the water level control, as well as the mud leg. I have no leaks, and it does not lose water - my weekly flush and refill is sufficient to maintain the water level. But I am still wondering if it is wise to try to do all of this work on such an old boiler? I'm concerned that messing around with the near boiler piping will crack the seals on the sections in the boiler etc.?
  3. The basement mains are not insulated (which I am planning to do) and was wondering if that insulation will make any difference for the issues I am having with the radiators?
I'd appreciate any thoughts you might have on this.

Let me know if you need additional information or pictures of anything in particular.
Thanks for reading my long story.
Single pipe steam
Weil-McLain EG/PEG -50
175K/145K in/out (454 sf)

Comments

  • Jamie Hall
    Jamie Hall Member Posts: 19,954
    What you are referring to as a drip loop is actually functioning as the boiler equaliser -- at least I don't see another one anywhere. And, as you note, the arrangement of steam mains does leave something to be desired...

    While a dropped header isn't really necessary, it certainly won't hurt, but arranging a horizontal header -- dropped or not -- with the riser at one end, then both steam mains off the top, then a proper equalizer -- should help. Make sure the header pitches somewhat to the equalizer end -- and make sure that any pipe size reduction for the equaliser takes place on the vertical.

    Now if those steam mains pitch back to the boiler (counterflow), while you are at it add a good sized drip to each one, taking off before they come down to the header and dropping below the water line before they join in a wet return.

    Remember to do all this in threaded black iron -- not copper.

    How much all this would reduce your heating bill is impossible to state -- but it should make it quicker to heat and much easier to get even.

    You are quite right -- the pipe size for your north loop is too small. In fact, way too small. It should also be 2 1/2 inch -- even 2 inch is still too small if it is counterflow.

    You only have one riser, so messing with the piping shouldn't be a problem for the boiler -- with one condition: if you have difficulty getting the old copper pipe out, don't. Instead, cut it and put a copper to thread union fitting on the stub a few inches up. I'd leave that nice king valve off -- you don't really need it, or you could leave it an make your transition to threaded right there.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    Powe
  • mattmia2
    mattmia2 Member Posts: 6,655
    How long does it take to heat? it is wrong but if it heats quickly you can probably balance it with venting. The cold room probably needs another or very large radiator. Even very good windows are more lossy than a poorly insulated wall.

    Others can comment on the amount of EDR on the main.

    Are the mains parallel flow, do the far ends connect to a return? A given pipe size can serve more radiation if it is parallel flow.

    Insulating the pipes will help.
    PoweLong Beach Ed
  • Powe
    Powe Member Posts: 16
    Thanks for the reply Jamie!
    My mistake calling the equaliser a drip loop. I'm still new to this. I'd never seen a steam system until 2-1/2 years ago when I bought the house. I've read Dan Holohan's book and listened to a lot of podcasts, done a bunch of research online, etc. It's been a steep learning curve.

    It's a parallel flow system. The North and South loops join on the other side of the basement where a single vent is installed for both lines after they join together. From what I understand, these loops should have separate vents. This goes through a steam trap and into a condensate tank with a boiler feed pump. (This is another energy waster I think as the tank holds at least 10 gallons which has to be heated up before the water going back into the boiler is even warm.) ... but I digress...

    It is a parallel flow system but the first 12 feet or so of the South loop slopes back to the boiler, so all the condensate from that is returning through that copper riser.

    Thanks for the reminder that pipe size reductions need to be vertical. This system has a couple of reducers on the main loops and they did not use offset reducers so there's a puddle behind these reducers.

    Interestingly, the copper riser from the boiler has a reducer (3 to 2-1/2) 0immediately after the threaded adapter that threads into the boiler. I'd like to get rid of that too!

    There's a few other oddities on this system that I haven't mentioned here because I know they need to be corrected eventually, like a 1" riser that goes to the third floor, but someone tee'd off at the second floor to serve that copper fin tube radiator... (cringe!!!!). I just haven't started the renovations in that area of the house yet.

    Here's where the two loops join before going back to the steam trap and condensate tank. There were two vents here when I bought the house. One was in the way of a new beam that had to be installed and I called a company to move it. They told me I didn't need it and this is the way they did it. Plus they kept the vent they took off.
    As it was originally:



    As it is now:


    Thanks for reading!



    Single pipe steam
    Weil-McLain EG/PEG -50
    175K/145K in/out (454 sf)
  • Powe
    Powe Member Posts: 16
    mattmia2 said:

    How long does it take to heat? it is wrong but if it heats quickly you can probably balance it with venting. The cold room probably needs another or very large radiator. Even very good windows are more lossy than a poorly insulated wall.

    Others can comment on the amount of EDR on the main.

    Are the mains parallel flow, do the far ends connect to a return? A given pipe size can serve more radiation if it is parallel flow.

    Insulating the pipes will help.

    Mattmia, thank you for responding to my post.
    If you are asking how long after the boiler fires til I get heat in the radiators, it is not long, but the North loop takes longer than the South. So the venting changes that were made (see my post above) have probably affected this issue as well. But I have a feeling that any amount of venting is not enough to compensate for the undersized North main.

    Yes, that "cold" room is certainly an inefficient room, but it's a glorious room!
    This is a pano shot so some of the lines look a bit wonky.


    Yes, it is a parallel return. see my comments and pictures above where the other end of the mains connect together.

    I already have the insulation for the pipes.
    Single pipe steam
    Weil-McLain EG/PEG -50
    175K/145K in/out (454 sf)
    CLamb
  • Jamie Hall
    Jamie Hall Member Posts: 19,954
    Those two loops joined together and vented is one of those subtle no-nos that sometimes gets overlooked. What happens is that whichever loop gets steam to the vents first closes the vents -- and then any air left in the other loop has to escape through the radiators, if it can get out at all.

    Revise that so there are two drips, separate, going down to the wet return, and then vent each line separately. That will make the whole thing much happier. Not fix all the problems, but surely get things much more under control Really not that hard to do -- sort of thing a good plumber could do on a warm morning when the system was off. If there is no wet return there -- looks like there may not be -- then the solution is to create two "water seals" at that location, and tie them into that copper return. All a water seal is is a loop of pipe which goes vertically all the way down to the floor, then turns and comes back up -- this case to that copper pipe. So long as you have at least 28 inches of height from the return line down to the loop for each pound of pressure the system runs at (it has to be measured from the return line because of the condensate tank), water will accumulate in the loop and will prevent steam from passing from one main to the other. Also something a good plumber could do pretty quickly.

    You probably don't need the condensate tank and pump at all, but we'll cross that bridge later. The system will probably work better without it!
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    mattmia2Long Beach Ed
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 12,654
    edited November 21
    @Powe

    B4 you do all that work which may not make a difference (yes, your boiler piping is wrong and the 1 1/2" main is to small) there is one problem that you must fix.


    Your two return lines look like they are tied together above the boiler's water line. This causes steam from the big main to close the vent b4 the small main get's vented so the small main remains air locked (except for the radiator vents.

    Before you do anything connect the return lines together below the boiler water line (no higher than the lowest gage glass tapping.....and lower if possible.

    And put vents on the end of both mains...big vents....especially on the small main. You want steam to get to the end of both mains about the same time.

    I bet it will work and you may not have to make the other changes until you replace the boiler
    MikeAmannLong Beach Ed
  • mattmia2
    mattmia2 Member Posts: 6,655
    So here is the question, what are the symptoms of that main being too small?

    Maybe steam is actually following the larger main out that way since they are joined.

    Is the room with all the glass in a place where you could connect the needed emitters to the larger main(maybe stub that out while you fix the vent)?

    I think it is worth thinking about if the things that are wrong are really causing it to be less efficient or if they just are not the way it is supposed to be.

    Obviously fix the incorrect both mains in to the same vent and the too small emitter but the rest might not change efficiency much and might have a very long payback.
    Long Beach Ed
  • Powe
    Powe Member Posts: 16

    Those two loops joined together and vented is one of those subtle no-nos that sometimes gets overlooked. What happens is that whichever loop gets steam to the vents first closes the vents -- and then any air left in the other loop has to escape through the radiators, if it can get out at all.

    Revise that so there are two drips, separate, going down to the wet return, and then vent each line separately. That will make the whole thing much happier. Not fix all the problems, but surely get things much more under control Really not that hard to do -- sort of thing a good plumber could do on a warm morning when the system was off. If there is no wet return there -- looks like there may not be -- then the solution is to create two "water seals" at that location, and tie them into that copper return. All a water seal is is a loop of pipe which goes vertically all the way down to the floor, then turns and comes back up -- this case to that copper pipe. So long as you have at least 28 inches of height from the return line down to the loop for each pound of pressure the system runs at (it has to be measured from the return line because of the condensate tank), water will accumulate in the loop and will prevent steam from passing from one main to the other. Also something a good plumber could do pretty quickly.

    You probably don't need the condensate tank and pump at all, but we'll cross that bridge later. The system will probably work better without it!

    Of course. That hadn't yet crossed my mind that that main vent probably get closed by the larger South loop first. I will have to look at that the next time I have a chance. If you look in the background of my "As it is now" picture, you can see a reducer in the horizontal main, which reduces that I-1/2 loop down to 1-1/4. There used to be a ceiling radiator there but I took it out and plugged the tap for it because the radiator itself was completely plugged up. I was thinking it might help to add a vent there.

    In regard to the condensate tank, I've seen that comment before that it may be unnecessary (might have been you in my first post on this forum). That tank holds a lot of water that has to be heated up by hot condensate returning before I have any hope of getting any warm return condensate. But yes, a discussion for another time.

    Your suggestion of putting in a separate water seal on each of the mains is good. I can do that easily too. I will need to order another vent sooner than later, before I do that..

    I will report back after checking which line closes that vent.


    Single pipe steam
    Weil-McLain EG/PEG -50
    175K/145K in/out (454 sf)
  • Powe
    Powe Member Posts: 16
    mattmia2 said:

    So here is the question, what are the symptoms of that main being too small?

    Maybe steam is actually following the larger main out that way since they are joined.

    Is the room with all the glass in a place where you could connect the needed emitters to the larger main(maybe stub that out while you fix the vent)?

    I think it is worth thinking about if the things that are wrong are really causing it to be less efficient or if they just are not the way it is supposed to be.

    Obviously fix the incorrect both mains in to the same vent and the too small emitter but the rest might not change efficiency much and might have a very long payback.

    I don't think steam is back feeding from the South loop into the North loop, but I am going to watch for that the next time I have a chance.

    Yeah, the efficiency is not something that is easy to quantify.

    FYI, this system runs at very low pressure. I added a low pressure (0-3psi) gauge to the system because the 0-30psi showed NO pressure. I have never seen the 0-3psi gauge go over 0.5 psi. As far as I know, there are no leaks in the system that I am aware of.
    Single pipe steam
    Weil-McLain EG/PEG -50
    175K/145K in/out (454 sf)
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 4,271
    Can steam heat travel thru green pipes? You better check with @DanHolohan. You may need to paint them black or silver before you put all that insulation on there. I don't see any arrows on those pipes, so they must be on the inside... Good, so the steam knows which way to go.
    Edward Young
    Retired HVAC Contractor from So. Jersey.
    Services first oil burner at age 16
    P/T trainer for EH-CC.org

    Powemattmia2MikeAmann
  • Powe
    Powe Member Posts: 16

    @Powe

    B4 you do all that work which may not make a difference (yes, your boiler piping is wrong and the 1 1/2" main is to small) there is one problem that you must fix.


    Your two return lines look like they are tied together above the boiler's water line. This causes steam from the big main to close the vent b4 the small main get's vented so the small main remains air locked (except for the radiator vents.

    Before you do anything connect the return lines together below the boiler water line (no higher than the lowest gage glass tapping.....and lower if possible.

    And put vents on the end of both mains...big vents....especially on the small main. You want steam to get to the end of both mains about the same time.

    I bet it will work and you may not have to make the other changes until you replace the boiler

    This makes perfect sense now that it's been pointed out. Typical rookie mistake to overlook this!
    That being said, I have followed the steam around the mains in the basement as the boiler is firing and both sides are heating from the boiler supply end of the pipe, but I was not alert to this issue of the race to close the steam vent! So I will have to check if that happens.

    Single pipe steam
    Weil-McLain EG/PEG -50
    175K/145K in/out (454 sf)
  • Powe
    Powe Member Posts: 16

    Can steam heat travel thru green pipes? You better check with @DanHolohan. You may need to paint them black or silver before you put all that insulation on there. I don't see any arrows on those pipes, so they must be on the inside... Good, so the steam knows which way to go.

    :D
    I use specially trained water that has GPS built in and I've laser etched a map at the top of the main riser which it has to follow, I add new recruits every week and flush out the lazy ones that just sit at the bottom of the boiler and collect mud. No matter how much I pay for water, I still get a bunch of the useless ones that only like to collect mud. It's such a PITA!
    Single pipe steam
    Weil-McLain EG/PEG -50
    175K/145K in/out (454 sf)
    EdTheHeaterManMikeAmann
  • Powe
    Powe Member Posts: 16
    Wow, so much has become clearer to me since thinking my way through all of this. This truly is something, you can only see in your mind.

    Sorry for the long post ... again!

    First, I've monitored the steam on both loops moving toward the trap and the small north main beats the larger south main to the vent every time, by about 12 ft of pipe.

    This means the both loops are closed before steam from the south loop gets to the vent. The assumption (I think) was that the steam in the larger south loop was beating the smaller north loop, thus halting venting on the north main with longer waits for the rads on the north loop to heat.

    The way it is, it would cause problems for the rads on the south loop, but:
    • The last radiator on the south main is about 25 ft from the vent.
    • The last radiator on the north main is about 8 ft from the vent.
    So when the vent closes, the steam is already past the last take-off on the south loop. No need to heat any of that last 25 ft of the south loop. In fact no need for any of that 25 ft to be a 2" pipe. I can drop the south loop to a wet return just past the last take-off and vent it there. I can then recycle the 25 ft of 2" pipe and use it to upgrade the north loop. This will also get rid of several places where that 2" pipe is a real headbanger! (now I'm getting excited!!!)

    I can also lose that last 8 ft of pipe on the north loop that is also a headbanger, and drop it to join the wet return coming over from the south loop. (Really excited now!!!)

    Without isolating the vents, the current arrangement results in a loss of heat potential on the north loop if the venting on the radiators on the south loop is greater. Or it could result in weird steam flows when the system is operating with the vents opening and closing on both loops. the system could change from parallel to counter flow in parts of the system depending on which vents are open or closed.

    Could this be the cause or contributor to why my pressure gauges read zero MOST of the time while the system is operating?

    For this heating season, I will work on isolating the loops so that the venting can be controlled on each loop separately and I'll take care of the big changes next summer.

    Note: currently, every radiator on the system has a #5 vent (Maid-o-Mist/Jacobsen). I've ordered some vents of different sizes to try to balance the venting and see if I can distribute the heat to where it is needed more.

    Let me know if you think I'm way off base on anything.

    Thanks again for reading my (long) story.


    Single pipe steam
    Weil-McLain EG/PEG -50
    175K/145K in/out (454 sf)
  • Jamie Hall
    Jamie Hall Member Posts: 19,954
    You're doing fine. Carry on!
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    Powe
  • Powe
    Powe Member Posts: 16
    edited November 24
    I know this may be radical thinking but is there any reason I should NOT use (i.e. 1" pex) for the wet return? It has already been used as a drip line on my second floor fin tube radiator which I want to get rid of. As far as I can tell, the only thing that temps over 200F will cause is less resistance to bursting under pressure and there's no (real) pressure on a wet return. So any other reasons to not use pex?
    Single pipe steam
    Weil-McLain EG/PEG -50
    175K/145K in/out (454 sf)
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 4,271
    edited November 24
    On steam, even condensation can be hotter than the maximum temperature rating of PEX. Stick with metal. even if it is green
    Edward Young
    Retired HVAC Contractor from So. Jersey.
    Services first oil burner at age 16
    P/T trainer for EH-CC.org

    PoweMikeAmann
  • mattmia2
    mattmia2 Member Posts: 6,655
    edited November 24
    If the boiler is matched to the connected emitters it should never build pressure. Pressure only builds if the emitters can't consume all of the steam the boiler produces. Of course if the boiler is underfired or undersized or has a hole so some of the steam is gong up the vent then it may not be able to heat all the emitters or you might need to be very careful about balancing venting to get it to all heat.
  • ethicalpaul
    ethicalpaul Member Posts: 3,910
    It would be fine, but probably best not to.
    1 pipe Peerless 63-03L in Cedar Grove, NJ, coal > oil > NG
    Long Beach Ed
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 12,654
    I would not use Pex on steam or condensate. Copper below the boiler waterline is ok
    Long Beach Edbburd