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One Pipe Steam System Flooding

SFbirdSFbird Member Posts: 103
Hello again! Maybe you remember my epic thread regarding a new Peerless steam boiler installed in September. We have been going along pretty well here, just about to get our Tekmar Controls installed, but some problems still keep cropping up. We had a few incidents where there was water coming out of our new Gorton main vents in the garage accompanied by more radiator noise. Our plumber (who I have had to guide using all the good advice I get from this website) addressed this "flooding" problem by draining/blowing down the boiler. Things were okay for a few weeks. We then started getting increased radiator noise and yesterday radiators on one riser are not heating up beyond just lukewarm even though they are still noisy...

Noise can range from standard steam hammer clanging to that sort of low roiling/rumbling sound like the boiler is surging again (dirty water?).

Where do you suggest I begin with this? Skim the boiler again? See if the auto-feed / minimum water level is the culprit?

Do you think since the system has "flooded" at least 2x in the past 5 months, that we need to flush the risers/return pipes since they could be full of crud now?


  • RJRJ Member Posts: 483
    fill valve

    Not sure if you have checked the fill valve assy. closely.  Most Mcdonnel Miller LWCOs  have a replaceable valve that can get corroded and plugged up allowing inlet water to seep by the valve seat,  they can plug up within 3 months if you dont change or clean the strainer basket. I had a job where after 2 weeks the boiler would be flooded, found the sa-51-101-102 was corroded inside, I replaced the valve assy. on the no.51 LWCO.   no more flooding.   be careful with these valves as excessive water press. on valve inlet on start up can damage valve. also you should inspect the float assy. sometimes they can develope a hole or colapse.  I recommend completely going through LWCO (low water cut off ) annually.
  • SFbirdSFbird Member Posts: 103
    Thanks RJ

    I will pass this along to my plumber.

    If the sight glass is full to the top when the boiler is not operating that means it's flooded right? Of course this is happening on the coldest day here this year (at least it's still above 40).
  • BobCBobC Member Posts: 4,406
    turn it off

    Drain the boiler down to the proper level and turn the supply valve to the auto feeder off, then it'can't flood from that source. If you use a tnkless coil inside the boiler for your hot water that could also leak.

    I've lived with steam heat for 65 years and never had an auto feeder on any of them, as far as I'm concerned they are more trouble than they are worth as long as the home owner checks the boiler frequently and the boiler has a WORKING LWCO.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • SFbirdSFbird Member Posts: 103
    No Tankless Coil

    We have a separate hot water system.But I think it is code here that we have to have an auto feeder for the boiler.
  • SFbirdSFbird Member Posts: 103
    Another Opinion

    Had another set of eyes on this today. He thinks we need to get rid of the back flow safety valve on the wet return to the boiler, also re-pipe the water make-up line to the return so cold water is not hitting the hot boiler water. Also he thinks our header pipes are not pitched sufficiently. We need to flush our wet return line because there is water backing up into the mains and he suspects that crud and that safety valve (possibly clogged) are part of the problem. We did not flush the returns before the new boiler was installed. Here is a pic of the headers and the water feed lines as they are now.
  • RJRJ Member Posts: 483

    Did they check fill valve ?
  • RodRod Posts: 2,067
    Boiler Flooding Problems

    Hi- Sorry to hear you are still having problems. It sounds as though this "second opinion" guy has a better sense of what is going on. There shouldn't be a check valve on the wet return pipe and it probably isn't a good idea to pipe cold water straight into the boiler as it is being done now. Whether the headers need to be repiped, it is hard to tell from the pictures. As long as they are level or have some slope in the appropriate direction, they should be okay. I would get the wet return problems straightened out first.

    You have 2 steam mains so therefore you are most likely to have 2 return lines going into the Wet Return. Was he able to locate both these lines?

    The Wet Return, since it is the lowest point in the whole system, is where are the dirt and crud settle out. Most of the other piping, since they carry steam, are generally quite clean (being steam cleaned constantly! :)  The Wet Return should have been cleaned or renewed when the new boiler was installed. It's a good idea to pipe the wet return with fittings so it can be flushed out occasionally.

     The pictures you posted show two sides of the boiler. Could you post some pictures of the other boiler sides especially it there is piping there?

    - Rod
  • SFbirdSFbird Member Posts: 103
    HI Rod!

    Yes, I am back again...sadly!

    Original installer is back now, I told him to start by flushing that condensate return line going all the way from where it drops from the vent back to that "flow valve check" near the boiler. It appears there is just that one wet return line. I am also having him check our Gortons to make sure they are not gunked up from the boiler flooding.

    I have mixed signals on that flow valve check, asked the major seller of Peerless boilers here about it and got this:

    Regarding the "flow check valve" located on the copper condensate return line running

    alongside the floor.  What is known, is that low pressure steam heating systems are

    sensitive to changes of the "A" and "B" dimensions which affect return water

    and if they are improper, the flow check valve is a solution to prevent boiler water from

    backing up into the return. This is sometimes the result of changing an older boiler

    with one of a different normal water working level."

    So, do I need it or not? If it will only give us trouble I am thinking it's best to toss it?

    Here are more piping shots too....

  • BobCBobC Member Posts: 4,406
    edited December 2012
    Check valve

    The problem with a check valve is it's a great place for a clog that can recur so don't be surprised if it happens again.

    Have your plumber check to see if there might be a problem between the water level of your new boiler and the steam system it's working with. This will give you some information

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • Paul48Paul48 Member Posts: 4,228
    edited December 2012
    Check Valve

    The check valve should go away. The "A" dimension is not suggested, it is required. Without it, you're not getting condensate back to the boiler.
  • RodRod Posts: 2,067
    Need to Find the Second Return

    If the auto water feeder is not leaking, then the problem is most likely a slow return of the condensate to the boiler. This may be due to a partially blocked wet return. Though I first think you need to resolve what happened to the second return as that maybe contributing to the slow return. The situation is this:  You have two steam mains!  The chances are that you have what is called a parallel steam system and therefore each steam main have to have its own return pipe so that the condensate (water) can return to the boiler!  Two Mains = Two Returns!

    I’ve attached a diagram of a typical 1 pipe system. Note the return pipes DO NOT join together until they are below the boiler’s waterline height in the Wet Return.

    As I remember it we talked back in September(?) about a Gorton main vent and how it was very close to the “A” dimension height before and that it needed to  be raised up closer to the ceiling.

    This piping apparently is one of the returns which when it drops down to floor level becomes what is know as the Wet Return.  Between this point on the floor below the Gorton, and where the piping attaches to the Equalizer Pipe on the boiler, there should be another pipe joining the Wet Return. This other pipe is the return from the other steam main.  If this return pipe can’t be found then we have to determine what happened to it as it has to exist other wise how does the condensate (water) get back to the boiler?  

        (There is a slight possibility that the other steam main is configured as what is called a counterflow main and therefore doesn’t have a return pipe though I seriously doubt if this is the case with your system.)

          Wasn’t this basement area renovated recently? If we can’t find another pipe connected to the Wet Return, what are the chances that the return pipe from the other steam main has been connected somewhere in the walls / ceiling to the return piping we see going down to floor?  As mentioned above the return pipes MUST NOT connect before they are below the boiler’s waterline. The big thing is we need to do is find the other return pipe! What does the “second opinion” guy say about the “missing return”?

    As for the check valve, it won’t correct an “A” or “B” problem on a gravity return.

    - Rod

  • Jamie HallJamie Hall Member Posts: 6,653
    I've only just returned

    to the Wall, so it is quite possible that I've missed something which has already been examined.  If so, forgive me -- and ignore me!

    Where is the water line of the new boiler with respect to the old one?  It should be the same, give or take an inch or two.  If it is significantly different -- either significantly higher or significantly lower -- it can really mess up the returns -- turning what was once a wet return into a dry return, or vice versa.  Either situation will cause problems.

    In a very limited sense, Peerless does have a point: a check valve on the return will prevent water from backing out of the boiler.  But as has been noted, it won't help in getting water back into the boiler (which is needed!) and it may get in the way.  It should not be used as a band-aid to fix a misplaced water line.  In fact, it shouldn't be used.  The Hartford loop will prevent catastrophic loss of water from the boiler if a wet return should leak.  Lose the check valve...

    The headers might be a tad low, but probably not -- they'd be about the last thing I'd mess with, as it looks as though they were put together pretty well.

    Do figure out how condensate from the second main gets back to the boiler...

    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England.

    Hoffman Equipped System (all original except boiler), Weil-McClain 580, 2.75 gph Carlin, Vapourstat 0.5 -- 6.0 ounces per square inch
  • BobCBobC Member Posts: 4,406
    2nd main

    I would go over every inch of that other steam main and investigate any pipe that comes down from it. If you find none, put a level on the main and see if it is sloping back towards the boiler. You have one main that is parallel  flow but the other could be counterflow, not usually done but you never know.

    Also consider what everybody is saying about that check valve, it really will be nothing but a perpetual problem because that is a very dirty area in a steam system.

    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • SFbirdSFbird Member Posts: 103
    the other wet return

    Hi Rod,

    Yes! There is another condensate return that joins the one in our garage where that main drops down in the corner. We had that angle you are speaking about returned to it's original 90 degree elbow so that the gorton on top is located almost 3 ft higher than when I sent you those first photos. I will send pics later of the new piping. As to that second condensate line, it is there joining in that corner on the floor, with the one that runs back to the boiler. What I don't know is where it starts, or drops down from the main on that side of the building. There is another garage in that area with storage cubicles that I may or may not have access to because some residents lock them. I will see what I can find out- Do you think a vent should also be on that main where it drops down too?

    The plumber flushed the condensate return line from that gorton in the corner back to the flowcheck valve in the boiler room, and he removed that valve completely.

    He also did some re-piping for the make up water supply line after I told him what the Peerless Sales guy told me. I will send photos shortly so you can tell me if everything looks better. The heat has been working well with no noise at all since this was done yesterday.

    To refresh your memory from September, here is a pic of that corner showing the old "drop angle" where the (possibly too low) vent was. As I said I pushed our guy to reconfigure that so now it is a reg. right angle,  with the Gorton connection up by the ceiling. The other pic shows the other mystery wet return joining in the corner below.

    I will update w/ new pictures soon!

  • SFbirdSFbird Member Posts: 103
    Got Rid of that Flow Check Valve

    We followed your good advice here and also the advice of our Excellent Second Opinion person we had out to look yesterday morning. The one condensate return line also got flushed and they did some re-routing of the make up water line to the boiler. I will send pics soon!

    System is running good and quiet now but I think the real test will be how it is doing in a few days/weeks. 
  • Paul48Paul48 Member Posts: 4,228

    Where's the other return?
  • SFbirdSFbird Member Posts: 103
    gonna go looking for it...

    It might drop down someplace in the front of the building that I can't readily access, like inside of a storage unit, but I will try my best. It probably needs a vent on that main too since I am assuming it is like everything else was before I got input from you folks- neglected, with NO VENTING!
  • RodRod Posts: 2,067
    Main Vents& Wet Returns

    Hi-  Good work! Finding the second return is a big step in getting your system straightened out.

           Main Vents- Each steam main needs to have its own main vent(s)!!!  The vents need to be located at either piping location as shown in the drawing I attached in the previous post.

    On this new "found" return it should be either on the main after the last radiator piping is attached or as you mentioned, on the return piping before it drops down to floor level. Since you have a fairly large steam system, you may need to have multiple main vents at each venting location. I would use Gorton #2 s and arrange them on an "antler" or "menorah". I'm not sure it I sent you this drawing before but have attached a copy to this post. You can start with a single Gorton #2 on each main though I think you will probably want to add at least one or two more

    I didn't know that you had raised the location of the main venting on the first return. I'm glad that this was done as it was very close to the "A" dimension and would easily have flooded out if the pressure wasn't kept low. Having the check valve on the Wet return didn't help this situation either and it's good that you have had it removed.

    Flushing- You need to have the whole Wet Return (included the "found" return) flushed.


    the lowest pipe in the system and being horizontal, this is where all the

    dirt,,rust etc.from the whole system collects. I've attached a drawing

    showing a flush setup for a Wet Return. You would want to remove the

    valve handles and store them so someone couldn't play with the valve and

    shut it off. This setup isn't a "must" but is nice to have as it makes

    it easy to flush the Wet Returns so you might want to install it somewhere down the line.

    i would install a main vent(s) on the second return and have the wet return portion of that return flushed. Hopefully that will speed up the return of the condensate from the system to the boiler so that the auto fill isn't triggered.

    - Rod
  • SFbirdSFbird Member Posts: 103
    pics of "found return" and new make up water line location on boiler

    As promised earlier.  As you will see, I only found the top part of where the other condensate return starts to drop to vertical. It is angled at the top and this is original to the building as far as I know, not moved for our retrofit work. I can't  access the storage area on the other side of that wall where I think the rest is visible, until the owner of that unit unlocks it for me. From what I see so far, unless an old vent is hidden  in the wall someplace, it does not have one at all.

    Also included shot of "fixed" pipe configuration in the corner where it drops down to the two adjoining condensate returns w our new gorton 2. We have two other gorton 2's at the end of the steam mains, front of property, where you advised me to locate them in Sept.
  • SFbirdSFbird Member Posts: 103
    That Second Main is Vented

    We do have a single Gorton 2 at the END of that second main ( before the riser) that I just found that wet return line for. Do we need another where that  condensate line drops down now in that storage area or could we get away with what we have or adding more at just the end of the main?
  • RodRod Posts: 2,067
    Main Vents

    Hi- I seem to be a couple of chapters behind on the saga. I was under the impression that the onluy main vent was the one in the garage that you have moved up since then.  Okay...If I have this right you now have a single Gorton #2 at the end of each steam main?

    You don’t need any vents on the returns as all you are interested in is that steam gets to the last radiator on the main (which means, of course, that it gets to all radiators between the boiler and the last radiator) We don’t car if air stays in the system after the last radiator as it doesn’t affect steam getting intothe radiators. In fact it is a waste of steam having it go all the way along the return to a Main Vent just before the return drops down into the Wet Return. If you notice in the drawing of a 1 pipe system I posted earlier it refers to the vent position at the end of the return as “an alternate” meaning that it for some reason it isn’t feasible to place Main Vents at the end of the steam main they will still work in the “alternate” position”

      Assuming that you now have a single vent at the end of each steam main you may want to remove the vent in the garage and using  an “antler”,add it to the presnt vent on the end of the main.  Have 2 each Gorton #2 (s) at the end of each steam main would probably be very beneficial.

    Wet Returns- Has the whole wet return back to the 2 nd return been flushed ? Was there a lot of dirt in the wet returns?

    Make up water- Okay, let’s see if I have this right– You now have the cold make up water from the Auto Water feeder going into the Equalizer pipe?  If so, this is a Big No - No as it places cold water in with live steam. The cold water will collapse (condense) the steam and you will probably get water hammer!  It would be much better to configure the piping so that the cold water enters the system in the Wet Return as this allows it to mix with the warn water in the return before entering the boiler. (See attached picture)  

    Over all things seem to be improving. I think getting rid of the check valve and flushing the Wet Returns will probably cure most of the “slow” return problems.

    - Rod
  • SFbirdSFbird Member Posts: 103
    Equalizer vs. Return for Make Up Water

    Hi Rod. I'm slightly traumatized now.

    Second Opinion Guy who looked our piping yesterday morning said the same thing you are saying: Pipe the make up water line into the wet return.

    However, the rep at Power Boiler where all the Peerless Boilers come from in this part of the world sent me this in response to my question about it:

    "Regarding the cold water makeup into the boiler - This is a gray area when reading the

    boiler and McDonnell Miller installation instructions. Neither indicate where the makeup

    water should be introduced.  It is however, good engineering practice for this water to enter

    into the boilers "equalizer" (not shown in pictures but was located on the left hand side)

    thus blending the cold with the heated boiler water.  The equalizer connects the steam

    header with the boilers return condensate and is the vertical pipe connecting the two.  The

    systems return and feedwater connection should enter at between 3 - 4" below what's

    known as the normal water level."

    I think my Original Installer followed this advice when he re-routed the pipes yesterday afternoon. Do I need to have him redo this now to the wet return??

    He flushed the condensate return from that garage corner where that Gorton is on the top of the drop-down, all the way back to where he removed the flow check valve (or about 2 feet from the entry to the boiler). Not very specific with me when I asked how much crud came out of the line.

    He did not flush the other portion of the "newly discovered" wet return that snakes through the storage room from that other part of the building. This is the problem with Original Installer: He is very nice and willing to follow up (eventually) but totally not proactive. I have to learn myself and then ask him to do stuff. Was ready to hire Second Opinion Guy and call it a day but everyone here sort of feels like this stuff is part of the original scope of a boiler installation, most of the bill has been paid on that.

  • Paul48Paul48 Member Posts: 4,228

    Given that the Hartford Loop should be 2" below the NWL, that connection should be below that. Is it?
  • RodRod Posts: 2,067
    edited December 2012
    Light at the End of the Tunnel

    Hi- Like the Power Boiler man said, where the new water enters the system, is a "gray" area.  As long as it is a minimum 3 or 4 inches below the waterline you should be okay.  I was a bit worried as normally you don't tee the new water into the equalizer pipe and with the insulation in place, I couldn't see exactly where it joined the pipe.

    (Is the Power Boiler guy the same person who said the check valve was okay?)

    I think I'd just go with what you have at the moment and see how that works. By eliminating the check valve, things should now probably be okay. I would consider in the near future adding more Gorton #2 (S) so you have a pair of them at the end of each steam main. I think this would be very beneficial to getting good steam distribution.

    - Rod

  • SFbirdSFbird Member Posts: 103
    I need to measure that distance....

    To be sure if it is below the Hartford Loop. Can you guys tell me from my pics where the Hartford Loop connection is, I know it's left side of boiler but I am clueless otherwise. I guess I can always refer to the owners manual....
  • SFbirdSFbird Member Posts: 103
    Okay, but.....

    Power Boiler Rep man was the one who gave me that "neither here nor there" response on the flow check valve that I posted earlier. That is why I was freaking out because you (Rod, who helped me so much) seem to be on the same page as Second Opinion Guy, who my husband and I both think knows his stuff, without question.

    I will try and watch the sight glass this weekend and see if the water is still bouncing around but so far the system is quiet (up here on the third floor at least) and we have heat in all radiators.

    If you were to tell me I should absolutely push Original Installer to re pipe into the wet return, then I might. My husband could probably go back and bounce it off of Second Opinion Guy too since he just used his company to install two giant boilers in a 1929 high rise downtown. Too bad we didn't use him over here at our little condo and learn I guess.
  • Paul48Paul48 Member Posts: 4,228

    As long as it appears to be below the NWL, I'd let it go.
  • RodRod Posts: 2,067
    edited December 2012
    System Flooding

    Hi-  I agree with Paul.  As long as it isn’t causing a problem (like “water hammer”) it will be okay. It is a better location than the previous one as the cold water gets a chance to be tempered a bit before entering the hot boiler.

      I can appreciate the dilemma you’re in when you get conflicting opinions especially when they come from people who are supposedly experts in their field. As you have been working your way through this I can see that you are gaining a lot of knowledge and insight as to how steam systems work.  If you don’t have it already, I think you might enjoy reading “The Lost Art of Steam Heating”

    It will fill in and clarify all of what we have been talking about and with that knowledge you have now you should have no problem understanding it. It’s not like a typical text book and once you get into it a bit you'll find, like a good novel, it is hard to put down.

    You mentioned that you are thinking about installing a Tekmar 279 in your building. Be sure to use the Search section to look up past posts on the Wall as there are a lot of good ones on the 279 from people that have it installed.

    Hopefully with the removal of the check valve from the Wet Return and the cleaning, this will speed up the return of condensate to the boiler so that the Auto Water Filler isn’t triggered. If this situation continues, get back to us as there are other alternatives to solve this problem. Ideally you want to make the return system you have (gravity return) work as it is the most simplest and therefore the most fool proof.

    - Rod
  • Paul48Paul48 Member Posts: 4,228
    Just Curious

    What kind of response have you gotten from the other folks in the building? Your efforts goes way beyond what could be expected from an individual owner. What are you going to do with all the spare time you'll have, when you finally get everything straightened out?
  • RodRod Posts: 2,067
    Hartford Loop Measurements

    Hi Again- Sorry, I missed your last post on the Hartford Loop measurements.  Attached are the measurements you need. On the drawing I referenced the page in the I&O manual so you can look it up if you need more information.

    - Rod
  • SFbirdSFbird Member Posts: 103
    Thanks For that Hartford Loop info...

    Regarding the Tekmar: Second Opinion Guy suggested that we will be asking for headaches with that boiler control. He thinks it might be too difficult / complex / tweaky to deal with  We were on the verge of getting going with installing it but he thinks we should seriously consider using Macon One Pipe Steam TRV's and also a more sophisticated timer on the boiler instead. I think you guys had mentioned the TRV's in the past so what do you think?

    I did actually order that other book from this site, the one titled something like "100 Things that can Go Wrong With Your Steam System, with Solutions". I was just going to bill it to our HOA Association and start a little library shelf down in the boiler room. Maybe that other book will be next!
  • SFbirdSFbird Member Posts: 103
    Everyone is Either Happy About It, or Totally Clueless

    I think even our Property Management Team has very little idea how these systems actually work and they rely on the contractors to be on top of it. Let's just say I got pretty fired up when our previous boiler nearly corroded away from lack of attention. Once the HOA Board decided to spend the money to replace the boiler it was pretty irritating when Original Installer started the thing up and all we got was tons of noise, etc. 

    The other two Board members (besides my Husband) really appreciate my efforts as do other neighbors who are actually aware of what has been happening. We also have a few owners here who are so checked out that they never said anything, even when we had steam hammer going through the whole boiler cycle.  I see this whole thing as just trying to protect our investment here, even if it's just a little shoebox condo in Earthquake Land.
  • RodRod Posts: 2,067
    Controls for Steam

    Boiler Controls- For condos and apartments the two controls commonly used are:

     1. the Tekmar 279

     2.  the Heat Timer

       Both are fairly sophisticated units and you would want to make sure that would have adequate tech and service support for either units. One of the features you want to have is “outdoor reset”as this has the potential for saving a lot of fuel. It takes into account the outdoor temperature and adjusts the length of the heating cycle.

       Your  “Second Opinion Guy” seems to be fairly knowledgeable. I would ask him what specific product he would recommend and why?

       The TRVs might be a good way to go but keep in mind that with 1 pipe TRVs  you need the burner to shut off occasionally and the system pressure to go to zero so that air can re enter the radiators. If you use TRVs what ever control you use would need to be able to take this into account.

    - Rod
  • Paul48Paul48 Member Posts: 4,228
    Found Return

    That photo of the elbow as it passes through the wall of the storage unit appears to be "straight on". I'm curious about the height ( "A" Dimension)
  • SFbirdSFbird Member Posts: 103
    Control Options

    Second Opinion Guy suggested TRV's and some sort of more sophisticated timer on the boiler so that individual homeowners would have more control over the temperature in the various rooms with radiators in their condos.

    We were ready to go with the Tekmar 279 + a better, seven-day timer (what we have now is a very basic timer with no range of settings, just AM, PM, on/off times for both).

    I was a little concerned because our building has a "warm side" that faces south and the colder , shady north side. Also the top floors are much more exposed to wind because that part of the building has no neighboring buildings right up against it ( buildings next to us are 2 story, we have 3). Unless we have multiple indoor temp sensors, I don't know how we will be able to get the Tekmar settings right and it sounds like it might be sort of a nightmare?

    Whatever we do, Original Installer is not going to do this part of it, we will use Second Opinion Guy's company or the plumber whose name I got here back in Sept./Oct.
  • SFbirdSFbird Member Posts: 103
    Still Can't See the rest of that Vertical Return

    I have not been able to access the other storage locker on the other side of that wall to look at where the rest of that vertical drop eventually meets the wet condensate return on the ground . The locker can't be opened until Wednesday when the owner gets home from her vacation. What I did see is that there is a concrete shear wall there that was put in during our earthquake retrofit and I am hoping that they didn't enclose the pipe in the concrete. There is a space between that wooden wall you see at back of storage room and the concrete: it is at least 5 in deep so it should be in there. I might need to have the wood removed to see where that diagonal that you see joins the vertical to give you that dimension. I guess I could get an estimate by measuring where that pipe goes into the wood wall, will need to see if the owner of that locker ( who is NOT an easy person) will let me in to do that....

    Either way, I am now obsessing about having that section of the wet return flushed as well, would have been nice if my Original Installer had noticed that maybe it should have been done at the same time as section going to the boiler from the other vertical drop.
  • RodRod Posts: 2,067
    edited December 2012
    Control Systems

    Hi- After reading your description of your building’s temperature variations, I can see that if you were trying to just balance the system using ordinary radiator vents, you would have a hard time achieving a satisfactory result.  In this situation using a control system incorporating TRVs seems like the best way to go. Basically all that needs to be done is make sure the coldest units (the north side) get the heat they need to be comfortable. Obviously this would mean that the warmest  units (the south side) would then be overheated so the TRVs would be used to control this overheating. (Always keep in mind that TRVs ONLY control overheating!)

    Straight timing controls are a bit archaic in this day and age.  Most controls now have timing and also both indoor and outdoor sensors. ( BTW the Telkmar 279 has its own timer) The placing of these sensors in the appropriate location becomes the big question and as the installer knows very little about the day to day variations, the resident’s input on this can help a lot. You might want to get a High /Low thermometer ( the mercury type work the best) and takes some readings in the colder areas of  the building.  You will probably find that although you only need TRVs in the over heated areas, every unit will want to have them. Keep in mind that the sensors can’t be installed in rooms (areas) that are controlled by TRVs as this gives a false reading to the control unit.

     Control systems are somewhat like steam systems in that you need to have someone install them that really knows what they are doing otherwise the results can be a nightmare.  Doing your “homework” goes a long way towards eliminating this predicament. I would get the manuals and brochures on the proposed systems so you can read up on it and also ask the installer where he has installed these units before and then check with the owners of these units as to how satisfied they were with the unit and the service of the installer.

        On the second return the big thing here is that there is plenty of over all drop to the wet return so as to cover the "A" dimension which means it needs to be a height of at least 28 inches above the Boiler's waterline and more is preferable. I wouldn't worry about the flushing of this return at this time as the work you had done so far (flushing the boiler end of the return and removing the check valve) may prove sufficient. I would still strongly suggest you get "The Lost Art of Steam Heating" as we could then reference you to a certain page. Dan's drawings and explanations far better than we could ever provide. This is a very useful book and has saved me well over a 100 times its worth which is why so heavily recommend it.

    - Rod
  • SFbirdSFbird Member Posts: 103
    TRV Question

    For one pipe steam systems do you guys like the Danfoss or Macons better?
  • RodRod Posts: 2,067
    Macon vs Danfoss

    Hi- I have both and both are both good units. Be sure that when you price them out that they are compete. The Macon comes complete but with the Danfoss is priced as components and usually doesn't include the vent. The Macon has an external vacuum breaker where as the Danfoss vacuum breaker is internal..When you order them make sure they are the ones for a 1 pipe steam system. I’ve attached some info on them  Quality wise they are very close though personally I think the Macon has a slight edge

    You will be satisfied with either one.

    - Rod
  • SFbirdSFbird Member Posts: 103

    Your opinion is very helpful! It sounds like we still need a control + timer on the boiler itself along with the TRV's? Anything less complicated than the Tekmar D279 ( and maybe less expensive)?
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