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A Steam Odyssey (Part 2): Midco Low-NOx Burner

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Comments

  • Dave in QCADave in QCA Posts: 1,440Member ✭✭
    another article on 2-pipe

    Boiler Pro, aka The Steam Whisperer also did another article on 2 pipe system.  Same ideas as the first paper, but he was proposing the use of orifices to provide even distribution instead of the "slow" vents proposed for 1-pipe.

    I can attest that it has worked for me on my 2 pipe system.   I fire at 75% of the normal recommended rate for the connected EDR.  It works very smooth.
    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
    · ·
  • Dave in QCADave in QCA Posts: 1,440Member ✭✭
    AMAZING!

    Mark, I am somewhat at a loss for words.   This is an excellent groundbreaking project!  The first application of the new Midco that we have seen!  It seems to be everything that everyone has been anticipating.   And, your AMAZING modulating, weather based control panel.  



    WOW!!!!
    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
    · ·
  • Noise

    A nice thing about the noise is that it is mostly from the air intake fan.  You can connect the fan to an intake pipe from outdoors to really quiet the burner down.  You could probably build a sound absorbing box and connect the intake to that with an intake opening to the box appropriately placed.
    The Steam Whisperer (Formerly Boilerpro)

    Chicago's Steam Heating Expert





    Noisy Radiators are a Cry for Help
    · ·
  • MarkSMarkS Posts: 462Member ✭✭✭
    Thanks Dave!

    This has been an incredibly rewarding project, though not without risk. I usually prefer to avoid the "bleeding edge" and let somebody else prove a new technology first, but as a controls guy this was too good an opportunity to pass up. Heck, even coal boilers a hundred or more years ago had mechanical mechanisms to regulate them.



    As with any new applied technology there are a few kinks to work out of the system, both the Midco and my controls.



    Stack temps are still too high, and the Midco folks are working on that. I'm told they have several boilers in their lab, and I'm trying to find out what they're using that's closest to the firing rate of mine. Incidentally, the guys at Midco have been great to work with and are committed to see this succeed.



    On the controls side, it really looks like the temperature override control won't be needed at all given the stack temps we're seeing. It's an opportunity to revisit the current control strategy and add new features that will allow even more flexibility for experimentation.
    Links: EcoSteam | A Steam Odyssey | Odyssey 2 | Odyssey 2014 | A Steam Enthusiast's Outdoor Reset Control
    Royersford PA | 1890 one-pipe steam system | 3009 sf | 3 floors | 14 radiators | Utica SFE boiler
    Midco LNB-250 Modulating Gas Burner | EcoSteam modulating controls | 70 to 300 MBH |
    607 sf EDR connected load | Operating pressure: 0.5 oz | 4 mains, 135 ft | All Gorton vents
    · ·
  • Stack temps?????

    Are you running a chamber liner?  With that burner, it's probably unneccesary and removing it would probably help radiant transfer really improve.    The radiant output for that burner is supposed to be very high compared to standard gas burners.
    The Steam Whisperer (Formerly Boilerpro)

    Chicago's Steam Heating Expert





    Noisy Radiators are a Cry for Help
    · ·
  • MarkSMarkS Posts: 462Member ✭✭✭
    Chamber liner

    Yes, there's a liner in the firebox. Isn't it supposed to protect the castings from flame impingement?



    I'm willing to try removing it, but what's the risk? How do I know if we've done the right thing?
    Links: EcoSteam | A Steam Odyssey | Odyssey 2 | Odyssey 2014 | A Steam Enthusiast's Outdoor Reset Control
    Royersford PA | 1890 one-pipe steam system | 3009 sf | 3 floors | 14 radiators | Utica SFE boiler
    Midco LNB-250 Modulating Gas Burner | EcoSteam modulating controls | 70 to 300 MBH |
    607 sf EDR connected load | Operating pressure: 0.5 oz | 4 mains, 135 ft | All Gorton vents
    · ·
  • JStarJStar Posts: 2,322Member ✭✭✭
    Liner

    I thought about leaving the bottom blanket out. I thought that the small casting space at the bottom would cause too much bubbling and turbulence if it heated a lot faster than the rest of the boiler. It's worth experimenting with, though.
    · ·
  • MarkSMarkS Posts: 462Member ✭✭✭
    Liner

    The liner is just on the back wall and the bottom, correct? Nothing on the sides?
    Links: EcoSteam | A Steam Odyssey | Odyssey 2 | Odyssey 2014 | A Steam Enthusiast's Outdoor Reset Control
    Royersford PA | 1890 one-pipe steam system | 3009 sf | 3 floors | 14 radiators | Utica SFE boiler
    Midco LNB-250 Modulating Gas Burner | EcoSteam modulating controls | 70 to 300 MBH |
    607 sf EDR connected load | Operating pressure: 0.5 oz | 4 mains, 135 ft | All Gorton vents
    · ·
  • Liner

    Yep, it there for flame imingement, but the flame is so tight on that burner it is probably not a problem. I don't know how big the chamber is, but it relatively easy to find out if it will work. In the Slantfins Iv'e put in, I don't run a chamber with the burners I've used, (Heatwise and PF XM) and haven't had a problem.  Thier flame is nice and tight. 
    The Steam Whisperer (Formerly Boilerpro)

    Chicago's Steam Heating Expert





    Noisy Radiators are a Cry for Help
    · ·
  • EastmanEastman Posts: 616Member ✭✭
    cheating

    Don't you want to do a fair comparison?
    · ·
  • EastmanEastman Posts: 616Member ✭✭
    combustion pressure

    What kind of chamber pressures do these boilers run at?  Is it acceptable to have a significantly higher level than ambient?
    · ·
  • MarkSMarkS Posts: 462Member ✭✭✭
    Control Software Features

    Here are some of the key features of the control software:

    1. Outdoor Reset Control using either time-proportional or heat loss mathematical models.

    2. Supports simple on/off burner control and the following types of modulating control: Fixed Voltage, Modulating on pressure only, Modulating with low temperature override. (Based on early results with the Midco burner I will be revising the control algorithms to allow more flexiblity in the modulating control modes)

    3. 7 day, 4 period-per-day temperature setback scheduling.

    4. 7 day, 4 period-per-day Domestic Hot Water heating schedule.

    5. Redundant indoor and outdoor temperature sensors, with configurable sensor selection (High/Low/Average/First Good).

    6. Automatic switchover to a good sensor if one of the indoor or outdoor sensors fails.

    7. Optionally retrieves current local wind-chill temperature over the Internet, and uses it as the outdoor temperature in outdoor reset calculations.

    8. In non-modulating mode, eliminates short-cycling on pressure by entering a pressure lockout mode if an adjustable high pressure limit is reached.

    9. On-demand DHW by pushbutton or when hot water flow is detected.

    10. Highly configurable – many parameters can be adjusted to tune the system to its environment.

    11. Logging of continuous analog data and heating cycle events, with trend charting for analog data.

    12. Logging of fuel consumption data for the preheat, heat-on, and DHW cycles.

    13. Automatically reverts to wall thermostat control in the event of a critical failure, or if selected by the user via a switch on the control panel. With the Midco burner, switching to "Thermostat" mode changes the burner control to a fixed voltage.

    14. The user interface is written in Java and will run on any Java-enabled computer - Windows, Mac, or Linux.
    Links: EcoSteam | A Steam Odyssey | Odyssey 2 | Odyssey 2014 | A Steam Enthusiast's Outdoor Reset Control
    Royersford PA | 1890 one-pipe steam system | 3009 sf | 3 floors | 14 radiators | Utica SFE boiler
    Midco LNB-250 Modulating Gas Burner | EcoSteam modulating controls | 70 to 300 MBH |
    607 sf EDR connected load | Operating pressure: 0.5 oz | 4 mains, 135 ft | All Gorton vents
    · ·
  • EastmanEastman Posts: 616Member ✭✭
    edited April 2013
    What is the address for the

    webcam?  I want audio with that too.  Have you heard anything more from Midco?
    Post edited by Eastman on
    · ·
  • MarkSMarkS Posts: 462Member ✭✭✭
    edited April 2013
    No webcam

    Sorry Eastman, no webcam. Not much to see on the outside anyway, all the action is in the firebox and inside the boiler. Neither of which are conditions that the average Best Buy webcam would survive for long. Would be great to see, though.



    No word yet from the Midco folks.
    Post edited by MarkS on
    Links: EcoSteam | A Steam Odyssey | Odyssey 2 | Odyssey 2014 | A Steam Enthusiast's Outdoor Reset Control
    Royersford PA | 1890 one-pipe steam system | 3009 sf | 3 floors | 14 radiators | Utica SFE boiler
    Midco LNB-250 Modulating Gas Burner | EcoSteam modulating controls | 70 to 300 MBH |
    607 sf EDR connected load | Operating pressure: 0.5 oz | 4 mains, 135 ft | All Gorton vents
    · ·
  • MarkSMarkS Posts: 462Member ✭✭✭
    Instrumentation and Controls

    The control system has two outdoor and two indoor temperature sensors. The pairs can be configured to use the first good sensor, a specific sensor, or the highest, lowest, or average of the two values. The system also fetches the wind-chill temperature from a local WeatherBug.com weather station over the internet; if the wind-chill temp is lower than the outdoor sensor value, the system will use the wind-chill temp in the outdoor reset equations.



    On the boiler there are temperature sensors for the tankless coil and the DHW temperature after the mixing valve, a type K thermocouple in the stack, and a 0-3 PSI, 4-20 ma pressure transmitter on the pigtail.



    Off-boiler there is a temperature sensor on the riser to the farthest radiator, and temperature switches on the steam header and the (newly divided thanks to JStar) large and small mains. There's also a flow switch in the DHW line that will heat water on demand (with a 3-4 minute heatup delay if the boiler's cold) during scheduled DHW "off" periods.



    I had good results with the Phidgets line of sensors on the previous version of this system, and selected their PhidgetSBC2 single-board computer as the platform to host the boiler control software. The SBC2 has an ARM processor and runs Debian Linux as the operating system. The sensors, control outputs, and control software are all on or interfaced directly with the SBC2; the system does not rely on a PC connection as was the case with the previous version. The user interface communicates with the the SBC2 over Ethernet on the home's local area network. While the SBC2 supports wireless, for this application I felt a wired Ethernet connection would be more reliable.



    Safety & Backup Controls



    The boiler is equipped with the usual safety features. On the 120 VAC side there's the Pressuretrol, LWCO, auto-feeder, and emergency stop switches at the boiler & in the cellar stairwell. During the conversion, JStar installed a flame rollout safety in the 24 VAC circuit to the Fenwal ignition control unit in the Midco cabinet.



    Because this is still in the experimental stages, I've included some additional backup features.



    There's a "Control Mode" switch on the front panel that selects between the Outdoor Reset/Modulating control, and the wall thermostat. In the "Thermostat" mode, a fixed voltage is supplied to the LNB burner. The control mode can also be selected from the user interface. And in the (hopefully unlikely) event of a computer or program failure, all of the control outputs are automatically set and held at their OFF state; this forces the system into Thermostat mode, and power must be cycled on the control box to return the system to modulating control.



    A vaporstat is installed on the pigtail, wired to make on cut-out and break on cut-in. It is set to cut out at about 3 ounces of pressure and to cut in at slight negative pressure. On cut-out, an interval time delay relay is activated that cuts power to the burner for 30 minutes. This was added in the previous version of the control software to eliminate end-of-cycle short cycling on pressure, the idea being that if you're building pressure in the boiler then the radiators are probably full of steam and continuing to run the boiler is just a waste of fuel. Now that the new system is controlling on pressure, in theory the vaporstat should never activate, but I opted to keep it in for when the system is running in the fixed-output "Thermostat" mode. This limit control is always active and operates independently of the boiler control software.



    There's also an emergency stop switch at the control box that removes power from the solid state relay that switches 120 VAC to the burner.
    Links: EcoSteam | A Steam Odyssey | Odyssey 2 | Odyssey 2014 | A Steam Enthusiast's Outdoor Reset Control
    Royersford PA | 1890 one-pipe steam system | 3009 sf | 3 floors | 14 radiators | Utica SFE boiler
    Midco LNB-250 Modulating Gas Burner | EcoSteam modulating controls | 70 to 300 MBH |
    607 sf EDR connected load | Operating pressure: 0.5 oz | 4 mains, 135 ft | All Gorton vents
    · ·
  • MarkSMarkS Posts: 462Member ✭✭✭
    User Interface

    I'll close this part of the saga with some pictures of the user interface.



    If you're ever in the Philadelphia area and would like to see the system in operation, send me a message through the forums or to mstayton (at) ieee.org, and we'll see if we can set something up.
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    ESFullScreen.JPG
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    ESClient-Settings-BurnerControl.JPG
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    ESClient-Settings-OutdoorReset.JPG
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    ESClient-Schedule.JPG
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    ESClient-Logs.JPG
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    ESClient-Settings-DHW.JPG
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    ESClient-Settings-Pressure.JPG
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    ESClient-Settings-Temperature.jpg
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    Links: EcoSteam | A Steam Odyssey | Odyssey 2 | Odyssey 2014 | A Steam Enthusiast's Outdoor Reset Control
    Royersford PA | 1890 one-pipe steam system | 3009 sf | 3 floors | 14 radiators | Utica SFE boiler
    Midco LNB-250 Modulating Gas Burner | EcoSteam modulating controls | 70 to 300 MBH |
    607 sf EDR connected load | Operating pressure: 0.5 oz | 4 mains, 135 ft | All Gorton vents
    · ·
  • LarryCLarryC Posts: 331Member
    Electrical surge suppressor and UPS included?

    Mark,



    Is the whole system protected by a decent surge suppressor.  I would be concerned about the solid state relays being taken out by a decent lightning strike in the area.  This is where I prefer mechanical relays for the additional isolation.



    Larry C
    · ·
  • MarkSMarkS Posts: 462Member ✭✭✭
    Surge protection & UPS

    No surge suppressor yet, but will be adding one soon. No plans at this time for a UPS.
    Links: EcoSteam | A Steam Odyssey | Odyssey 2 | Odyssey 2014 | A Steam Enthusiast's Outdoor Reset Control
    Royersford PA | 1890 one-pipe steam system | 3009 sf | 3 floors | 14 radiators | Utica SFE boiler
    Midco LNB-250 Modulating Gas Burner | EcoSteam modulating controls | 70 to 300 MBH |
    607 sf EDR connected load | Operating pressure: 0.5 oz | 4 mains, 135 ft | All Gorton vents
    · ·
  • Maine VentMaine Vent Posts: 117Member
    This is the Best Part of this Web Site

    Hi Mark,

    I want to thank you for such a fun and interesting thread. I have been following this project, and your web site and your software. I love this stuff, computer science programming, along with steam heating technology. You are a very smart and talented engineer. I have gotten so many great tips from the pros on here over the years, and your expertise is right up there with these Pros. My heating season is over here in Maine, I will take your advise and change out my cycle guard for a safe guard LWCO. My biggest complaint, is the same as yours. I have a backup safe guard LWCO.

    Thanks again for your great work.
    · ·
  • EastmanEastman Posts: 616Member ✭✭
    Thank you for sharing this project.

    Is anyone else considering this?
    · ·
  • tim smithtim smith Posts: 2,103Member ✭✭✭
    Re: your project and sharing

    Mark, this project is just too cool. I really appreciate your time in this and the sharing of your process and the results you are getting. If I had the time I would be a mad scientist all the time rather than just when the circumstances allow it.  Kudos to you and also thanks to Midco for this design and their involvement.   Ps, I would lose the blanket with this burner design as you should not see any impingement. Will be interested is if you see any stack temp drop if you do so. 

     The other boiler I would love to see this tried on is the Mega steam from Burnham, I know Steamhead would like that too.  Thanks again. Tim
    · ·
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