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Boiler room ventilation

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Lee1234
Lee1234 Member Posts: 1
in Gas Heating

I just moved into a 20 yo home with 2 Slant/Fin 322,000 boilers. The boiler room has high (yellow circle) and low (red circle) vents to outside air. Does this look okay? I'm wondering about the opening in the ductwork (green circle). Should I seal it with duct tape?

The room gets a lot of dust/dirt. How can I minimize that? Can I put a filter on the low vent or would that be unacceptable (and possibly against code)?

Thank you in advance for all help!

boiler-0.jpg boiler-1.jpg boiler-2.jpg

Comments

  • pecmsg
    pecmsg Member Posts: 7,319

    650K BTU’s

    This better be an apartment building!

    Mad Dog_2
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 12,550
    edited July 10

    I think it is a two bedroom Cape Cod with a really big snow melt system for the driveway @pecmsg. The driveway starts in Maine and ends up inn Cape Cod 🤣

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    pecmsg
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 12,550
    edited July 10

    I find this setup to be interesting. It appears to be a finished room, possibly on the first floor. That fan in the ceiling would be there to force air through the confined space. In my opinion, however, that fan should be pushing air into the room to provide combustion air and place the boiler room under a slight positive pressure.

    The question about using an air filter on the lower duct seems to contradict that, since filtering the air leaving the room would make no sense. That would suggest the ceiling fan is actually exhausting air from the confined space, making the lower duct the combustion air intake.

    If that is the case, it would place the boiler room under a negative pressure, and I don't think that is good for proper combustion. Installing a filter that restricts airflow as it becomes loaded with dust would only make the negative pressure in that room worse.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 20,557

    It will not put the boiler room in a negative if the intake duct is large enough.

    Any more than a boiler sending air up the stack will not make the boiler room negative unless the intake is too small.

    They are trying to exhaust heat out of the boiler room with the fan up high. The intake duct would have to be sized for the total boiler(s) combustion air + the air the fan exhausts. Duct looks like it might be 10 x 20"

    In addition the louver for the intake duct must be roughly double the duct area.

    EdTheHeaterMan
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 12,550

    @EBEBRATT-Ed , that is a good point. If properly designed, that intake duct should be able to maintain a neutral pressure. Adding an air filter may change that dynamic.

    I would prefer the fan to be on the inlet side, not the exhaust side, of that combustion air/ventilation system. Kind of like the Fan-in-a-Can concept, where the fan operates whenever the burner operates, and perhaps at a lower speed if it is also needed for heat removal in that confined space.

    That is what I would design. That is why I said it was interesting.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • JimP
    JimP Member Posts: 108

    That room looks to be so carefully done that I would start looking for design plans that might exist. 20 years isn’t that long ago and there must have been plans. Maybe the city has something if they’re not around the home? Where do those PVC pipes go to?

  • JimP
    JimP Member Posts: 108

    By the way…if it’s too hot why aren’t the pipes insulated?

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