Results 1 to 10 of 10
  1. #1
    Join Date
    Jan 2008
    Posts
    23

    Negative chimney draft after radon fan installation

    What do you think the best solution for this is? I dont want to arbitrarily instal a make up air kit that dumps outside air into the boiler room. I would like to find a set up that connects directly to the boiler to control the ambient room temp. and corrects the draft issue.

    Do you know if anyone makes such a unit to mount to a Viessmann boiler?

  2. #2
    Join Date
    Apr 2002
    Posts
    11,808
    http://www.tjernlund.com/commercialInforcer.htm

    maybe a cool building is making air fall down the chimney right now also

  3. #3
    Join Date
    Jan 2008
    Posts
    23
    Quote Originally Posted by Carnak View Post
    http://www.tjernlund.com/commercialInforcer.htm

    maybe a cool building is making air fall down the chimney right now also
    Thanks for the reply, but this is in a residential aplication, and I dont want to flood the room, but rather feed the boiler directly.

  4. #4
    Join Date
    Apr 2002
    Posts
    11,808
    condensing boiler piece of cake, but yours goes up a chimney

    here is the residential model, you set it to bring in how much air you need, it tempers the cold air with room air

    http://www.tjernlund.com/combustionairintake.htm

    it brings in air when the boiler fires and is off when the boiler is not firing

  5. #5
    Join Date
    Jun 2008
    Location
    Surrey, BC, Canada
    Posts
    35
    Hoyme out of Canmore Alberta makes a automatic vent damper that opens on a call for heat from the boiler. Once the damper is open, it triggers a end switch that allows the gas valve on the boiler to open. This system prevents cold outside air comming into the boiler room unless the boiler is on.

  6. #6
    Join Date
    Jul 2000
    Location
    Northern Wisconsin
    Posts
    2,006
    Quote Originally Posted by KTM-MIKE View Post
    What do you think the best solution for this is? I dont want to arbitrarily instal a make up air kit that dumps outside air into the boiler room. I would like to find a set up that connects directly to the boiler to control the ambient room temp. and corrects the draft issue.

    Do you know if anyone makes such a unit to mount to a Viessmann boiler?
    The first thing you should do is contact a Viessmann contractor and have them research whether the company has an authorized "fix" for your problem. Manufacturers frown (will sometimes void the warranty) when an aftermarket appliance is added directly to their product.

    As we don't have a radon problem in my area I haven't seen first hand what they do to deal with it, but I would think that pulling the entire structure into a negative would solve one problem while creating others as in your case.
    Use the biggest hammer you like, pounding a square peg into a round hole does not equal a proper fit.

  7. #7
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,929
    Interesting. Creating a second problem to cover up the symtoms of the first problem.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  8. #8
    Join Date
    Aug 2004
    Location
    S.E. Pa
    Posts
    6,180

    Exclamation

    Usuallly radon mitigation is subslab suction. If it is depressurizing the house, I would send them a certified letter return receipt and asking them what do THEY plan to do about the problem THEY caused. Most likely, all they have to do is find the leaks and seal the slab better. However, it does point out how sensitive this heater is so you will still need to determine the house depressurization limits through a Worst Case Depressurization Test and combustion analysis.
    As previously noted, MUA kits attached directly to a unit may void the warranty just as placing the unit in a negative pressure zone will. If they do not have a listed MUA kit, then you must provide MUA into the CAZ as prescribed in the codes then repeat your testing to verify it works.
    HTH,
    Hearthman

  9. #9
    Join Date
    Jan 2007
    Location
    Minneapolis, MN
    Posts
    415
    Turn off the radon mitigation system. The carbon monoxide from a back drafting appliance will KILL you way before you will ever need to worry about radon. Install a CO detector and get the venting/draft corrected ASAP.

  10. #10
    Join Date
    Sep 2007
    Location
    Chicagoland
    Posts
    46
    Call the radon mitigation co and find out what they say. From what I recall, the fans used in radon mitigation are not very powerful, especially compared with kitchen hood fans. The radon system is supposed to relieve pressure under the foundation slab, so unless your slab is very leaky, I find it hard to believe that you would get a bunch of negative pressure from just the radon fan. Typical installation of the radon system calls for sealing up most cracks, and sealing sump covers, etc to minimize this effect. Also, if they don't seal the sump covers, and larger cracks,the radon system will not work as well.

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