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Low pressure steam plumbing

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douglas1
douglas1 Member Posts: 1
Any advice would be appreciated. We run wein McClain boilers @ 15psi to steam seafood. What is the best way to plumb the system? Stay at 2.5" or go larger. Should I increase distance greater then 24 inches? Thanks in advance 

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  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,840
    edited March 21
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    You need swing joints. That piping design will cause the boiler to pry itself apart at the seems. Literally
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
    Mad Dog_2
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,840
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    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
    Mad Dog_2
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,840
    edited March 21
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    Since this is process steam, (not space heating steam) you may want to modify the recommended piping since there is no return condensation from the heating system. I have faded out the pipes that you do not need. I also recommend that you install the feed water on the equalizer piping to the bottom of the boiler below the water line.
    Since you will be running lots more fresh water thru this system, and you do not want to add chemicals to keep the corrosion to a minimum, this type of boiler system may need replacing more often than the ones we find in old homes that operate at less than 1 PSI for 40+ years or so..

    You may want to pretreat the fresh water before you feed it into the boiler in order to reduce the corrosion effect without chemicals. You do it with a 30 or. 40 gallon water heater and set the thermostat to 140°. Then you pipe the hot water to the boiler feed valve with a microbubble air vent to remove as much oxygen from the water before it enters the steam boiler. This may help the boiler last a few years longer. and water heaters are cheaper than replacing boilers. @DanHolohan offered up an article on this trick many years ago, and @Erin Holohan Haskell was able to find it for me the last time I told someone about it. The process steam was for baking bread or pretzels or something like that. Perhaps Erin can find it again for us?

    EDIT. I found it here. @Erin Holohan Haskell

    https://heatinghelp.com/systems-help-center/steam-boilers-in-food-processing-applications/
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
  • Erin Holohan Haskell
    Erin Holohan Haskell Member, Moderator, Administrator Posts: 2,286
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    Thanks @EdTheHeaterMan.
    President
    HeatingHelp.com
  • Sylvain
    Sylvain Member Posts: 125
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    Reading the text in the link, why not put the automatic water feeder at the inlet (cold side) of the water heater?
    EdTheHeaterMan
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,840
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    Sylvain said:

    Reading the text in the link, why not put the automatic water feeder at the inlet (cold side) of the water heater?

    That makes sense, but as the cold water in the water heater expands, it will increase in size. That increase in volume would raise the water line in the boiler like it does in an expansion tank in a closed system. If that increase in volume is not an issue then it would probably work.

    The other thing that causes water to release air is reducing the pressure. If the pressure in the water heater is kept at the inlet water pressure, the sudden drop in pressure would release more dissolved air microbubbles at the location of the valve as soon as the valve opens. If the air separator was located in the discharge side of the feed valve, AND at the location of the hottest water, that will be the most effective air removal location.
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,840
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    The original Question about the pipe size actually has not been answered. Should the header be 2-1/2" piping? That depends on the quality of the steam needed. If you need DRY steam to exit the boiler then you need larger pipes than 2-1/2" for the header. The process of opening a valve with 15 PSI of pressure (steam or otherwise) to the atmosphere, (like inside a cooking vessel that is not sealed like a pressure cooker) will cause a rapid flow of gasses and liquid to move at an accelerated rate. This illustration of the Weil-Mclain boiler with glass piping illustrates that the velocity of the steam leaving the boiler, to a valve open to the atmosphere will entrain much of the hot water from the surface of that boiling water https://www.youtube.com/watch?v=6kMzg05dh5A
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
    Intplm.
  • Sylvain
    Sylvain Member Posts: 125
    edited March 22
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    We don't know how the steam is used.
    continuously? or by spurt like in the bakery.

    In case of spurt, would some kind of a buffer steam tank be of any help?

    Working at 15 psi? that would open the pop up safety valve.

    https://brewingwithsteam.com/brewing-with-steam-blog/f/the-case-of-the-popped-relief-valve
    good story:
    https://brewingwithsteam.com/brewing-with-steam-blog/f/the-case-of-the-over-pressurized-boiler