The Wall
Forum / Strictly Steam / TwinBoiler Schematic
  • Post a Reply to this Thread

    TwinBoiler Schematic (27 Posts)

  • vaporvac vaporvac @ 11:41 PM
    Contact this user

    TwinBoiler Schematic

    We've finally finished a plan for the boiler install. These are two stage-fired Slantfin Intrepid TR50s paired with two Riello #G400 series .#C8554115 I'm looking for any feedback concerning the feasibility of this schematic and any changes or problems those experienced with their install can see.

    This is for a two-pipe Trane VaporVacuum system.  The thinking with this layout is as follows:  with this design there is still only one steam main leading up to
    the house supply. It allows us to have the two boilers close together
    with the fronts facing.outwards and gives exactly identical
    piping over to the main steam line.  We shouldn't need a condensate tank
    because the boiler levels will even out because each has its own
    condensate return with each boiler having a  Hartford loop and they are
    both connected together through the condensate return and the level in
    the condensate will even out in the two boilers.This will ensure
    the system is a closed one allowing a vacuum to be pulled. With this we won't need a condensate tank or two separate boiler pumps with boiler
    float level switches, both which would be difficult to seal and maintain
    a vacuum not to mention the increase in cost and complexity.
    The discussion on the consensate tank issue can be found here:  http://www.heatinghelp.com/forum-thread/146003/CondensateTank-Why
    The discussion of SFs piping diagrams as well as the diagrams themselves can be found here:
    http://www.heatinghelp.com/forum-thread/146002/Drop-Header-Which-way-to-Go

    I hope someone replies to this. I know it's late in the heating system, but we'll be working on this over the summer. Thank you everyone for the help thus far. Colleen
     
    This post was edited by an admin on May 27, 2013 12:16 AM.
  • nicholas bonham-carter nicholas bonham-carter @ 12:03 AM
    Contact this user

    twin boilers

    would a Gifford loop, be better at keeping the boiler levels under control?--nbc
  • vaporvac vaporvac @ 5:38 PM
    Contact this user

    More research...

    Thanks, NBC. I'm researching that today...reading through some old posts with queries from you as well as F. Gifford's site. I'd only associated the Gifford loop with one-pipe systems, but it looks like it can be used for two, as well.

    Hopefully, folks can look at all this near boiler piping and compare it to that in my prior post to see what might work best. I have time to get this right . At the moment I'm just try to get good dimensions to pour the new pad.
  • gerry gill gerry gill @ 8:54 PM
    Contact this user

    I dont see any reason

    Why what you sketched out shouldn't work just fine.
    Serving Cleveland's eastern suburbs from Cleveland Heights down to Cuyahoga Falls.
  • vaporvac vaporvac @ 11:33 PM
    Contact this user

    That's great news!

    I'm really happy to hear you think this would work, Gerry. It's a little different from what I've generally seen, but WM had something similar for twinning their boilers.

    Any thoughts on NBC's idea on using a Gifford loop vs. a Hartford loop?  I'm still not clear on how it's better, but if it's simpler or space conserving, I'm all for it.

    Does it look like this design enables us to eliminate the condensate tank?
  • Dave in QCA Dave in QCA @ 11:42 PM
    Contact this user

    comments

    Colleen,  This is looking pretty good but I have a couple comments.  Regarding the condensate tank, I think you mean the reservoir?  You won't know whether you will need that until you operate the system and see how slow you condensate comes back from the system and whether it causes a drop in your boiler water to the level that more water must be added, that eventually causes the boiler to be flooded when all of the water finally returns.

    Regarding the piping, I think you have got this very close, and if you did the drawing.... I am impressed indeed!  The problem that I see is that when looking at this drawing, and you are view the boilers from the back, each boiler has 2 risers, a header and an equalizer.  This is all good.  Then, each boiler has a steam supply the goes up and then drops into a pipe that I'll call the building header.  This head drips down and connects to the return of the boiler on the left.  This will cause the left boiler to over fill over time.  I don't seen any piping that will allow the water level of the boilers to equalize.  It seems to me that the return piping of the left boiler should continue on over to the right boiler, so as to tie them both together.

    I'm sure one of the pros, especially Dave Bunnell will jump in and comment on this if I am wrong.

    On  a few other notes, I owe you a few emails and hope to catch up soon when I am back home at my own computer.
    Dave in Quad Cities, America
    Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
    System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
    Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.
    http://grandviewdavenport.com
  • vaporvac vaporvac @ 12:56 AM
    Contact this user

    Piping,Reservoir tank

    Just lost everything I wrote! Ok. Thanks all. So I did mean reservoir tank. Will the boiler still flood without an autofeed as I don't plan on having one, at least to begin with? How do I plan for one as in placement and ensuring it feed the boiler evenly?

    Can I eliminate the returns coming off the mains since I already have equalizers on each boiler or should I just continue the line to the RH boiler. Concerning the condensate return line...would it be better to for a "T" between the two boiler to ensure they're fed evenly. I'm also just noticing I have the condensate going uphill at the end so I'll have to make sure it's head downhill instead.

    Dave, I just thought you'd gone MIA now that the warmer weather is here! Hope this is all making sense. Thank you again.  Colleen
  • vaporvac vaporvac @ 7:04 PM
    Contact this user

    ready to pull the plug...

    The new fireproof ceiling has been hung and the concrete pad will be poured on Thursday. Just thought i'd see if anyone had any last minute suggestions or comments concerning the piping diagram attached above, and the thinking leading to it.Se had tried to configure something with the boilers facing away from each other to have only one drop header feed, but couldn't figure out a take-off for the two equalizers or Hloops (although they may go gifford, the jury's still out on that). BTW these are two slantFin tr50s with Riello power gas burners, stage-fired.

    Thanks ahead for any comments.
  • Dave in QCA Dave in QCA @ 11:53 AM
    Contact this user

    Simplification

    Colleen, I have been wondering how your project was coming along. Glad to hear from you again!
    I have made some edits to your drawing as a suggestion to simplify the piping. Also, I think when you compare it to the Slantin documents you will find that it is consistent with their recommendations.
    Dave in Quad Cities, America
    Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
    System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
    Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.
    http://grandviewdavenport.com
  • vaporvac vaporvac @ 4:58 PM
    Contact this user

    Thank you, Dave!

    A much too belated THANKs for that schematic. It really got us thinking in a new direction as I didn't realize each boiler didn't need its own equalizer. I've sent your drawing with some changes to SF for approval. We have to reorientate the boilers as there wasn't enough space for servicing them in the original plan. No biggie and will make it much nicer to access. Consequently, we'll be dropping the heading in the other direction OVER the boiler. At least we hadn't poured the pad.
    SF is good in the tech dept, but it would have been nice if the piping diagrams for stage-fired boilers were a bit more explicit and easily found without have to fish around. Some diagrams aren't even on the site and nothing comes with the boilers. Probably the pros know their way around the system, but trying to design one is no cake walk. I guess that's why they're call PROs.
  • vaporvac vaporvac @ 8:56 PM
    Contact this user

    latest schematic, and hopefully last...

    So after fiddling around with sizes we've changed a few things around using Dave's schematic as the base. SF liked that one and said it would allow for a stable water line. Thanks again, Dave..
    These new ones have a few advantages and look more similar to SFs designs. Does anyone see any problems with either one? We're a little perplexed as to where to put the king valves to allow draining/cleaning so that's not set in stone. I'm also attaching a little scale drawing so you can see approximately where this fits into the scheme of the boiler room. 1sp=3".
    The risers are 3" dropping into a 3 or maybe 4" header. I have lots of 4" ipe from the old install. We wont pipe down the equalizer until further down than shown. Thanks all for taking a look at this. Hopefully SF approves as well. Colleen
  • MarkS MarkS @ 7:27 AM
    Contact this user

    King Valves

    Hi Colleen,

    If space permits, I'd suggest mounting the king valve for the left boiler in the vertical position, like the right one. Depending on the valve's internals, you might get a small amount of water pooling with the valve in the horizontal position.

    You're also going to need an isolation valve between the two boilers on the common return line. Otherwise, when you go to blow down the boiler on the right, you'll end up pushing the water to the left boiler. Also note that with the common return, you won't be able to blow down the left boiler while the right boiler is running. It's not a big deal, I just wanted to make sure you're aware of it.
    Homeowner, Royersford PA | 1890 one-pipe steam system | 3009 sf | 3 floors | 14 radiators | Utica SFE5200S boiler
    Midco LNB-250 Modulating Gas Burner | EcoSteam modulating controls | 70 to 300 MBH |
    607 sf EDR connected load | Operating pressure: 0.5 oz/in2
    Four main runs (insulated) totaling 135 ft in length | All Gorton vents on mains & rads |
    A Steam Odyssey | Odyssey 2 | Odyssey 2014 | A Steam Enthusiast's Outdoor Reset Control
  • vaporvac vaporvac @ 5:40 PM
    Contact this user

    45degs

    Thanks Mark. That's something i wouldn't have thought about. Just to be clear the drop is at SF's suggested 45deg angle, but it should work the same. I'm pondering the isolation valve...we just didn't want to screw with the original piping too much and wanted to maintain equal pressures and water lines. p.s. How's the midco working out?
  • MarkS MarkS @ 7:28 PM
    Contact this user

    Isolation valve

    Under operating conditions you'd leave the isolation valve open, so there shouldn't be any impact to pressure or water lines. You'd only close it when you were blowing down one of the boilers. I've edited your drawing to show the location of the valve in red.

    The Midco is running great. Had our first real heating day today, ran seven heat cycles with one or two more to go tonight. I'm collecting lots of data on system performance and will be posting reports periodically throughout the heating season.

    When's installation day?
    Homeowner, Royersford PA | 1890 one-pipe steam system | 3009 sf | 3 floors | 14 radiators | Utica SFE5200S boiler
    Midco LNB-250 Modulating Gas Burner | EcoSteam modulating controls | 70 to 300 MBH |
    607 sf EDR connected load | Operating pressure: 0.5 oz/in2
    Four main runs (insulated) totaling 135 ft in length | All Gorton vents on mains & rads |
    A Steam Odyssey | Odyssey 2 | Odyssey 2014 | A Steam Enthusiast's Outdoor Reset Control
  • Dave in QCA Dave in QCA @ 8:03 AM
    Contact this user

    looks good

    Colleen, the drawing both look good to me.
    Dave in Quad Cities, America
    Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
    System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
    Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.
    http://grandviewdavenport.com
  • Rod Rod @ 8:55 PM
    Contact this user

    Isolation Valves

    Isolation valves-  Mark's comments got me thinking that if you ever needed to take one of the boilers completely off line but still operate the other, you could do so by using each boiler's King valve but would also need a valve on each boiler's individual return line off the common return pipe (see attachment) . As it's very easy to over complicate things by coming up with contingencies for scenarios that are unlikely to happen, the isolation valves may not be needed /desired. I just thought I would mention it in case it might be useful to you.
    - Rod
  • vaporvac vaporvac @ 6:20 PM
    Contact this user

    Soon!!!

    Thanks for your comments and edits. Good points all and easier to incorporate now than as a retrofit. No date set yet...still trying to get everyone's schedules to jive. It will be a joint project between the pipe-fitting, burner install, venting and controls. I still have to order the vaporstat and Tekmar control mentioned in my other post. That seemed the easiest solution. We're also having the asbestos removed from the old Ideal coal behemoth. It's too near the new boilers to risk bumping into it all the time. Better to do it now than later.

    Did we ever get to see a pic of the installed Midco? I wasn't checking in as often over the summer. I have to live that dream vicariously!
    This post was edited by an admin on November 5, 2013 7:00 PM.
  • MarkS MarkS @ 8:16 PM
    Contact this user

    Midco

    Lots of pics of the Midco in April here: Midco

    Incidentally, I've recently decommissioned the Vaporstat I had on my system as a control (not safety) limit. It's a 0-16 oz model with a SPDT switch that I calibrated to be more accurate at the low end of the scale (0-4 oz). It's a little over 3 years old, and hasn't been tripped very often since I put in the pressure transmitter a couple of years ago. If you're interested drop me an email through the Wall.
    Homeowner, Royersford PA | 1890 one-pipe steam system | 3009 sf | 3 floors | 14 radiators | Utica SFE5200S boiler
    Midco LNB-250 Modulating Gas Burner | EcoSteam modulating controls | 70 to 300 MBH |
    607 sf EDR connected load | Operating pressure: 0.5 oz/in2
    Four main runs (insulated) totaling 135 ft in length | All Gorton vents on mains & rads |
    A Steam Odyssey | Odyssey 2 | Odyssey 2014 | A Steam Enthusiast's Outdoor Reset Control
  • vaporvac vaporvac @ 1:11 PM
    Contact this user

    Pressure Transmitter?

    OK...I'm definitely interested in that  Vstat, but what the heck is a pressure transmitter? You have the coolest stuff!
    Don't know how I missed those postings...a lot to see. I'll have to devote some some to that.  Again, the coolest stuff.
    This post was edited by an admin on November 6, 2013 1:15 PM.
  • Dave in QCA Dave in QCA @ 8:38 PM
    Contact this user

    I didn't mean to recommend

    TEKMAR. I have a tekmar in my building and for various reasons it works great. But, it does not give you 2 stage control. if you only have vaporstats to control hi-lo, it will start out on hi an run on hi until you build pressure. So, that means every single cycle will run both boilers. Now, another way to do this, if you have your heart set on the Tekmar is to add a single pole double throw switch into the circuit. I did, because I need it. In the auto position it allows the vaporstat to run the high fire according to it setting. In the LO position, it does not allow hi fire to operate. In the HI position, it hold the burner in high fire as long as it is firing. Of course, it will quickly shut off on the controlling vaporstat.

    Colleen, if I was hooking your system up I would do it the way Dave Bunnell did with a 2 stage thermostat. I simple 2 pole double throw switch can be used to switch boiler is lead and which is lag. It would just be wired in the thermostat wiring to reverse the connections with the flip of a switch.

    If you leave your thermostat setting alone, the only time the second boiler will run is when one won't keep up. That is the best for efficiency. Of course, if you have the t stat turned down and turn it up, then they would both run in this scenario too, until the temperature is satisfied, then one would shut off.... then eventually the other.
    Dave in Quad Cities, America
    Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
    System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
    Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.
    http://grandviewdavenport.com
  • vaporvac vaporvac @ 12:27 AM
    Contact this user

    Ooops! Taco, not Tekmar

    This is what happens when i rush. Total brain cramp there...this is what I meant to write concerning the controls re: Jstar   He advised using the Vaporstats to control staged pressure, and a two-stage
    thermostat coupled with a TACO 2-stage switching relay to control the
    boilers. I meant to write TACO , not Tekmar!  Do you think that is a good choice to switch from on boiler to the other?
  • Dave in QCA Dave in QCA @ 7:23 AM
    Contact this user

    Lead/Lag

    Ha ha ha. I know what you mean. Yes, while I am not familiar with the taco device, Jstar recommended it and he knows what he's doing. (understatement) I am sure it is a package device that allows you to switch which boiler is lead and which is lag.

    Perfect!
    Dave in Quad Cities, America
    Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
    System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
    Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.
    http://grandviewdavenport.com
  • Eastman Eastman @ 12:43 AM
    Contact this user

    Will steam find its way from

    one unit into the other?
  • JStar JStar @ 7:52 AM
    Contact this user

    TACO

    Here's the TACO 2-stage switching relay.

    http://www.taco-hvac.com/uploads/FileLibrary/102-418.pdf
    - Joe Starosielec
    732-494-4357
    j.star@thatcherhvac.com
    http://thatcherhvac
    http://facebook.com/thatcherhvac


    Guaranteed performance. Guaranteed energy savings.

    Serving all of NJ, NYC, Southern NY State, and eastern PA.
    Consultation anywhere.
    (Formerly "ecuacool")
  • vaporvac vaporvac @ 4:23 PM
    Contact this user

    Taco says "No"!!!!??????

    Jstar. I sent you an email.
  • JStar JStar @ 6:23 AM
    Contact this user

    TACO

    I responded to your email, but I'll make my opinion public, too.

    They would be fools to think that the control is only applicable to hot water systems. A relay is a relay is a relay. I don't care if it's running a pump, a boiler, or a hair dryer. If the electrical ratings are within spec, it'll work.

    We have 2 of these relays in commission and working perfectly. If we always listened to the manufacturer, we would be stuck 50 years in the past.
    - Joe Starosielec
    732-494-4357
    j.star@thatcherhvac.com
    http://thatcherhvac
    http://facebook.com/thatcherhvac


    Guaranteed performance. Guaranteed energy savings.

    Serving all of NJ, NYC, Southern NY State, and eastern PA.
    Consultation anywhere.
    (Formerly "ecuacool")
  • vaporvac vaporvac @ 9:05 PM
    Contact this user

    Thank you for your public and private response

    Thank you for your public and private response, but are you sure you weren't listening in on my conversation to Taco? Thanks for setting my mind at ease... it just didn't make sense what they were saying. However, I've had some folks refuse to believe that wet-based boilers can be used with a gas gun, even when the manufacturer says so!
    I think it's steam that's the problem...so few companies want to deal with it. I don't understand why as it's not like the the mod/cons are a piece of cake to install or maintain either. In the end, the American manufacturer loses as we seem to end up importing our technology instead of being the innovators. OK...off my soapbox!
  •  
Post a Reply to this Thread