Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Barametric Dampers

Jeremy Member Posts: 52
Could someone tell me the proper place to install a barametric damper? I've heard many different ideas and would like to know the correct way. Also is their a code published anywere that I could see regarding correct installations? Thanks in advance


  • keith
    keith Member Posts: 224
    barometric dampers

    should be installed as close to the chimney as possible. I am assuming you are talking about a chimney application. They also should be installed on the side of the smoke pipe with the saddle fitting that is supplied with them.Never install a draft damper in the run of a tee or use the tee as an elbow.
  • Alan R. Mercurio
    Alan R. Mercurio Member Posts: 588
    RE: Barametric Dampers


    A draft regulator shall be provided unless otherwise specified by the appliance manufacturer. The draft regulator shall be installed in accordance with local codes and regulations or in the absence of local codes, with the American National Standard NFPA31. Refer to appliance manufacturer’s instructions for recommended overfire and stack draft.

    Installing the Draft Regulator:

    The draft regulator should be installed in the stack between the chimney and the stack mounted primary control. It should be at least 10" to 12" from the control and preferably 18". If it is installed closer to the primary control, it may affect the proper operation of this safety control because of the possibility of relatively cool air from the open regulator door passing over the stack-heat sensing element (helix) of the control.

    When installed on a horizontal stack pipe, the draft regulator can be installed at a greater distance beyond, toward the chimney, from the primary control if necessary, or if it is desirable to use the stack pipe as a radiator to heat the room. In this case, install it close to the chimney. When the draft regulator is to be installed on vertically running stack pipe, locate as low as possible.

    The higher the draft control is located, the lower the setting needs to be. If located too high, a low enough draft setting may not be possible. The draft regulator is designed to operate properly when the hot combustion products are flowing at right angles to the tee of the draft control. It must be mounted so that it is level.

    The draft regulator also must be located at least 18" from a combustible wall or ceiling, as a fire preventive measure. It is common practice to install a draft regulator that is equal in size to the smoke pipe outlet of the furnace, boiler or water heater that it will service (the stack pipe is also generally that same size). This generally provides adequate capacity unless the chimney is very high or the draft setting to be maintained is very low. In no case should a regulator be used that is smaller in cross-section than the stack pipe.

    To establish low draft with a chimney that develops a high draft, it may be necessary to install two draft regulators to maintain the desired control.

    Your friend in the industry,
    Alan R. Mercurio
    Oil Tech Talk
  • keith
    keith Member Posts: 224

    are stack mounted primary controls still used on oil fired equipment? On new insatallations? Most of the guys in my area remove them and convert to Cad cell relays.
  • Alan R. Mercurio
    Alan R. Mercurio Member Posts: 588

    Hi Keith, Yes sadly enough they are still in use that's the only reason I mentioned them in the post above. I agree with you though I would prefer if one went bad to update the system with our more current technology. And to the best of my knowledge they are not used in new installations, at least not from what I have seen.

    Your friend in the industry,
    Alan R. Mercurio
  • Dale
    Dale Member Posts: 1,317
    Gas or Oil?

    If it's a gas installation for a conversion burner or power gas the damper blade swings both ways, oil only one way so poofs don't push oil smoke into the house. and is adjusted for overfire, instructions with it. If its oil the other guys covered the topic pretty well.
  • Draft Regulator

    placement on an oil appliance would call for it to be installed a minimum of 18" above or away from the boiler. Should be installed in the flow of the pipe and not the bull end of a tee. Attached is a scan of acceptable locations that we place in our installation manuals. Hope this helps.

    Glenn Stanton

    Burnham Corp.
  • PJO
    PJO Member Posts: 140
    Oooops (nm)

  • Alan

    What about using a stack control as a sort of backup to a primary cad cell relay ? It doesnt happen often , but sometimes a cad cell will fail and pump in oil to the boiler without shutting down .

    I remember once we ripped out a boiler with a Beckett and a cad cell relay . And in the flue was a small control that looked like a mini stack relay , but only had a thermostat wire going to it . I didnt look at the inside of it . You think that was some sort of purpose built backup ?
  • e-mail me your

    address and I will send you a book on barometrics.
  • zeb
    zeb Member Posts: 3
    tee used as an ell

    the directions supplied w/ the damper does show an installation using a tee as an ell
  • Jeremy

    The barometric damper on oil boilers should be at least 18" above or away from the boiler and mounted in a postion as shown in the scan attached. This is from one of our Installation manuals. Hope this helps.

    Glenn Stanton

    Burnham Corp.
This discussion has been closed.