Page 1 of 2 12 LastLast
Results 1 to 13 of 22
  1. #1
    Join Date
    Jul 2004
    Posts
    1

    Hmm

    how exactly does a flame sensor work? NOT the old MFS but the single wire ones.

  2. #2
    Join Date
    Jun 2001
    Posts
    3,910
    Do a search for flame sensor.

    Here's one to get you started
    http://hvac-talk.com/vbb/showthread.php?threadid=45541

  3. #3
    Join Date
    May 2000
    Location
    Colorado flatland native
    Posts
    15,067

    well, they put a little electricity in that rod

    if flame is touching it, elect. passes through the carbon in the flame, back to the burner.... Flame sensed.

    If electricity doesn't leave that rod due to no flame or corrosion insulating it, flame not sensed.
    My doctor gave me six months to live, but when I couldn't pay the bill he gave me six months more.
    Walter Matthau

  4. #4
    Join Date
    Apr 2002
    Posts
    11,808
    The flame rod is small compared to the burner.

    Alternating current goes to the rod and it will flow through the flame by "ionization" to the burner head.

    Because the current alternates, current is trying to go back from the burner to the rod.

    It is easy for the little rod to "hit" the big burner with current however it is hard for the big burner to "hit" the little rod with current.

    Because of this, current tends to only travel from the rod to the burner. It is like a half wave rectifier, similar to putting AC current through a diode and only getting pulsating direct current out.

    If the flame signal monitored by the gas control was alternating, it would shut off as it would mean there was a short.

    The way we build has a greater impact on our comfort, energy consumption and IAQ than any HVAC system we install.

    http://www.ductstrap.com/

  5. #5
    I don't understand all of your explanation. My burner is lighting, but the brand-new flame sensor is not sending the signal to the controller unless I run the propane/air mixture excessively rich. Can you elaborate any further.

  6. #6
    Join Date
    Nov 2011
    Location
    St. Louis
    Posts
    3,415
    Quote Originally Posted by seanyb1 View Post
    I don't understand all of your explanation. My burner is lighting, but the brand-new flame sensor is not sending the signal to the controller unless I run the propane/air mixture excessively rich. Can you elaborate any further.
    Call a technician for God's sake. Or we'll see you on the news or the Dark Side of the Moon.

  7. #7
    Join Date
    Jan 2007
    Location
    Stongsville Oh
    Posts
    899
    You asked how a flame rod worked, you got very good explanations of exactly that. There is more to a system than a flame rod. Now we find out why you asked. Call for service.
    ckartson
    I didn't write the book I just read it!

  8. #8
    Unfortunately, there are no service technicians available in my area. The explanation was rather nebulous- I now understand that current flows from the rod through the flame and on to ground via other research. The snarky responses are not appreciated.

  9. #9
    check out the explanation on the site http://hvacwebtech.com/Flame%20Rectification.htm

  10. #10
    Join Date
    Sep 2010
    Location
    Lake Ronkonkoma, New York
    Posts
    570
    This is not a do it yourself site. You got an explanation about how flame sensors works and you also received links for further study. What you won't get here is help blowing up your home and family. Look harder for a service tech.
    http://www.youtube.com/watch?v=M5QGk...e_gdata_player
    If the women don't find you handsome, they should at least find you handy.

  11. #11
    Join Date
    Nov 2011
    Location
    St. Louis
    Posts
    3,415
    "The heater then opens the gas valve. This signals the igniter which, when it hits the gas, will turn into a flame."

    Wrong.

    "However, when these systems use the same hot surface igniter for sensing and ignition"

    Wrong.

  12. #12
    "YE SHALL KNOW THE TRUTH, AND THE TRUTH SHALL SET YOU FREE" I agree that Snarky responses are no substitute for customer relations. It's not the facts (truth) that provides us with answers, It is knowledge of the truth. Unfortunately, the ability to convey knowledge regarding technical facts to a homeowner or customer is limited by the technicians ability to be free in his or her knowledge. As you have discovered, the words Flame Sensor are self explanatory. Flame sensing is a part of the "sequence of and is necessary for proper operation"
    Quote Originally Posted by seanyb1 View Post
    Unfortunately, there are no service technicians available in my area. The explanation was rather nebulous- I now understand that current flows from the rod through the flame and on to ground via other research. The snarky responses are not appreciated.

  13. #13
    Join Date
    Nov 2006
    Location
    Southeastern Pa
    Posts
    18,563
    It looks like another new poster, or two, or three failed to read the rules.

    I'm sorry, is that too snarky for you?
    [Avatar photo from a Florida training accident. Everyone walked away.]
    2 Tim 3:16-17

    RSES CMS, HVAC Electrical Specialist

    AOP Forum Rules:







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