Page 1 of 2 12 LastLast
Results 1 to 13 of 15
  1. #1
    Join Date
    Jul 2007
    Location
    Minnesota
    Posts
    21

    Fuel Oil and Gas

    I apologize if this is the wrong thread, but its the closest for my question. Are there any codes for the sharing of a fuel oil boiller flue and LP boiler flue within the same stack? Both flues go above roof line, but share the same rain cap. The LP is primary and fuel oil is back-up only. Any verification from NFPA or ASHREA would be helpful.

    Thank you,
    Attached Images Attached Images   

  2. #2
    Join Date
    Aug 2004
    Location
    S.E. Pa
    Posts
    6,164

    Cool maybe

    NFPA 211 and the 2009 IRC both allow common venting or interconnection between gas and oil. Solid fuel must have its own separate flue.

    You refer to same 'stack', which is confusing. They appear to share the same flue. Are there two separate flues within this one chimney-one for the oil and one for the LPG but both terminating under one large multi-flue cover?

    Those connectors look pretty big. A common vent or flue must be sized for the combined BTUs. Both appliances must have primary safety controls. Both have very little vent rise. I don't see a listed liner but I do see galvanized steel cemented into the wall which is not approved in 211.

    I would install a listed liner sized both both appliances and bring it in closer to the ceiling while maintaining clearances to combustibles. You would use type L vent near the ceiling for a 9" clearance to combustibles, manifold it, install separate barometric dampers with spill switches, etc.

    Any pics of the top of the chimney?

    Move this to Pro section and we can discuss sizing and other details.

  3. #3
    Join Date
    Apr 2011
    Location
    Coastal Maine
    Posts
    819
    This looks like a commercial or institutional installation. If that is the case, there may be other codes or standards that come into play by municipality and state.

    What is the building's usage?

  4. #4
    Join Date
    Jul 2007
    Location
    Minnesota
    Posts
    21
    Hearthman and Meplumber,
    Thanks for your timely responses. I will post a couple more photos for referencing; though crude.. they may assist with increased defining of use. The heating water is used for a large garage with docking access.

  5. #5
    Join Date
    Jul 2007
    Location
    Minnesota
    Posts
    21

    More photo's

    Here are a couple more photos of installation;
    Attached Images Attached Images    

  6. #6
    Join Date
    Aug 2004
    Location
    S.E. Pa
    Posts
    6,164

    Exclamation

    You have a problem there with that draft inducer/ power venter. It can generate positive vent pressure, which is not allowed in either vent system. Positive vent pressure can only be on one appliance regardless of fuel type and the venting must be listed for positive vent pressure. Just gooping joints with red RTV silicone does not count. Besides, in this application, it could easily vent from the WH back through the boiler into the room if the top of the chimney is blocked.

    Do you have a photo of the chimney taken from this county? A little far away...

  7. #7
    Join Date
    Dec 2007
    Posts
    4,685
    Quote Originally Posted by hearthman View Post
    You have a problem there with that draft inducer/ power venter. It can generate positive vent pressure, which is not allowed in either vent system. Positive vent pressure can only be on one appliance regardless of fuel type and the venting must be listed for positive vent pressure. Just gooping joints with red RTV silicone does not count. Besides, in this application, it could easily vent from the WH back through the boiler into the room if the top of the chimney is blocked.

    Do you have a photo of the chimney taken from this county? A little far away...
    not to hijack, but a similar question/situation;

    a NG natural draft H2O heater with an Iron Fireman oil furnace. Is the I.F. considered a power venter or induced draft and therefore okay? I have questioned this for years, have 3 homes this way of which 2 are former company owners homes.
    The Food Stamp Program, administered by the U.S. Department of Agriculture, is proud to be distributing the greatest amount of free meals and stamps EVER.
    Meanwhile, the National Park Service, administered by the U.S. Department of the Interior, asks us to "Please Do Not Feed the Animals". Their stated reason for this policy "... the animals become dependent on handouts and will not learn to take care of themselves."
    from an excerpt by Paul Jacob in Sun City, AZ

  8. #8
    Join Date
    Aug 2004
    Location
    S.E. Pa
    Posts
    6,164

    Cool

    PAC, your answer is not from the mfrs. propaganda but your manometer. If you read positive pressure in the vent connector, then you must treat it that way. This is under 'steady state' (as if that truly exists) or after 5-10 min. of firing.

    Note in the pic all the red RTV downstream of the inducer/ blower. Shouldn't be needed if nat. draft. If it truly just induces and vent pressure goes neg. then its ok for a minute or so......unless its dumping gobs of CO into the CAZ.

  9. #9
    Join Date
    Apr 2011
    Location
    Coastal Maine
    Posts
    819
    pac. The I.F. oil furnace is not positive draft. At least I have never seen one that was. As long as the flue is of the appropriate size and the smaller btu appliance (the water heater) connects to the chimney above the larger, then you are alright.

  10. #10
    Join Date
    Aug 2004
    Location
    S.E. Pa
    Posts
    6,164

    Cool neg draft pressure from I.F. 'furnace'?

    Apparently, we need some more info. here.

    Pacnw, can you provide a model I.F. burner? Also, this burner is on a furnace and not boiler?

    MEPliumber, all but one of the burners I saw on the I.F. site were forced draft according to the mfr.

    I have seen plenty of power burners and induced draft burners that end up with a negative draft pressure.

    I still say always test with a manometer to be sure then full combustion analysis to ensure it is burning properly and venting effectively.

  11. #11
    Join Date
    Apr 2011
    Location
    Coastal Maine
    Posts
    819
    All of the iron fireman oil products are considered unassisted draft. According to NFPA 31, if the burner provides all of the necessary draft to overcome the static pressure of the vessel, then it is not considered to be a positive draft situation.

    There are literally thousands of this combination all over New England. All legally installed and operated. Oil fired Furnaces with regular old tank type natural draft gas water heaters venting into the same flue. As long as it is common vented as I mentioned before, it is legal per NFPA 31, 211, and 54.

  12. #12
    Join Date
    Aug 2004
    Location
    S.E. Pa
    Posts
    6,164

    Smile

    Not looking to pick a fight meplumber--just curious about your source of info. on the I.F. being nat. vent. As I stated, I went on their website and about 90% of their units were listed as "forced draft" which means positive vent pressure. If you have a reference that contradicts this such as possibly for older units in the field, that's fine.

  13. #13
    Join Date
    Apr 2011
    Location
    Coastal Maine
    Posts
    819
    No reference on their newer stuff. All of the I.F.'s that I service are at least 15 years old. Many much older. The only reference that I have is just my experience. I will try and take a couple of pics the next time I service one. I might get lucky and find an old I & M lying around.

    I just looked at their newer specs. Your right. Learn something new everyday. To be honest I wasn't sure that they were still in business.

    Thanks.

Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event