Page 1 of 3 123 LastLast
Results 1 to 13 of 37

Thread: flame sensor?

  1. #1
    Join Date
    Nov 2012
    Location
    Royal Oak, MI.
    Posts
    8

    flame sensor?

    First off I am fresh out of school so pretty green but would like a few opinions on a furnace I'm trying to get going for a friend.
    Lennox 90% Furnace starts up normally but flames get sloppy within a few seconds then go out and starts over. the code says flame sensor but the flame on burner the sensor is on gets sloppy very fast and not sure sensor has time to heat up. I have cleaned it with brillo, same outcome and sensor looks really good. combustion air switch checks out good.

    orderd new flame sensor so figured I would run by y'all while I wait.

    Thank you for your time, Scott

  2. #2
    Join Date
    Jan 2007
    Location
    N.E. Ok.
    Posts
    1,370
    Clean the burners and crossovers and check gas pressure.

  3. #3
    Join Date
    Jun 2004
    Location
    Eugene, Oregon
    Posts
    1,018
    Does the flame get sloppy when the fan comes on?
    "The bitterness of poor quality remains long after the sweetness of low price is forgotten". --Benjamin Franklin
    "Don't argue with an idiot, they will drag you down to their level and beat you with experience". --Mark Twain
    http://www.campbellmechanical.com

  4. #4
    Join Date
    Feb 2008
    Location
    Altmar, New York, United States
    Posts
    4,653
    have you checked the air intake? you should not use a brillo to clean a flame sensor. use a bill. if the flames are getting sloppy i wouldn't think the flame sensor is at fault. what was the gas pressure?

  5. #5
    Join Date
    Nov 2012
    Location
    Royal Oak, MI.
    Posts
    8
    Flame gets sloppy almost immediately

  6. #6
    Join Date
    May 2012
    Location
    Upper Michigan
    Posts
    3,588
    The flame sensor is the safety not the problem, what model?

  7. #7
    Join Date
    Nov 2012
    Location
    Royal Oak, MI.
    Posts
    8
    that is what I thought, G26Q3-75-6

  8. #8
    Join Date
    Jun 2004
    Location
    Eugene, Oregon
    Posts
    1,018
    My guess is that you're not getting a good draw through the heat-exchanger. Either your inducer draft motor is not working right or you have a restriction in the combustion air path. Check your intake, exhaust and heat-exchanger. Could also be a breach in the heat-exchanger not allowing the inducer fan to create the necessary draw.
    "The bitterness of poor quality remains long after the sweetness of low price is forgotten". --Benjamin Franklin
    "Don't argue with an idiot, they will drag you down to their level and beat you with experience". --Mark Twain
    http://www.campbellmechanical.com

  9. #9
    Join Date
    May 2012
    Location
    Upper Michigan
    Posts
    3,588
    Quote Originally Posted by addiscott View Post
    that is what I thought, G26Q3-75-6
    I've seen the secondary's plug on these and there under warranty. Pull the inducer and make sure the wheel is good and maybe the cover on the secondary side.

  10. #10
    Join Date
    Feb 2010
    Location
    Calgary, Alberta
    Posts
    1,111
    I'll bet the secondary is plugged from years of poor drainage.
    Pull the collector box and have a look.

  11. #11
    Join Date
    Nov 2012
    Location
    Royal Oak, MI.
    Posts
    8
    Thanks alot! As I said I'm a little new but I shouldn't have second guessed myself. This is the track i was taking but supply house said flame sensor.

  12. #12
    Join Date
    May 2012
    Location
    Upper Michigan
    Posts
    3,588
    Quote Originally Posted by addiscott View Post
    Thanks alot! As I said I'm a little new but I shouldn't have second guessed myself. This is the track i was taking but supply house said flame sensor.
    Idiots!

  13. #13
    Join Date
    Mar 2005
    Location
    burlington county n.j.
    Posts
    9,743
    if the flames are sloppy right after ignition look for intake or exhaust restrictions.
    if flames get sloppy when blower starts look for a big crack in the primary heat exchanger just inside of the burners.
    early G26 furnaces had a burner alignment issue that let flame impinge on wall of heat exchanger, new HX comes with burner assembly that MUST be used.

Page 1 of 3 123 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