Page 1 of 3 123 LastLast
Results 1 to 13 of 27
  1. #1
    Join Date
    Nov 2004
    Location
    Colorado Springs
    Posts
    51
    Hello all,

    My ICP Comfortmaker furnace is well maintained (even the blower bearings are oiled!!), and I am extremely happy with its dependability, but every couple of years, it develops a false start problem, and its always the same reason -- the flame sense rod has finally become dirty. A quick cleaning with fine steel wool, and everything's great again. I do have some curiosity-type questions however:

    1. What exactly is the material building up on the rod? Is it just normal byproducts of combustion of natural gas? Or is it an indicator of some type of impurity in the gas/air?

    2. Is the flame sense rod solid all the way through, or is it plated with some special metal (and will I eventually wear through that metallic plating?)

    thanks,

    novice 39


  2. #2
    Join Date
    Mar 2005
    Location
    Suppy NC
    Posts
    4,516
    a combanation of everything
    as long as the the porsilan isnt cracked steel wool wont hurt
    the rod is solid

  3. #3
    Join Date
    Nov 2004
    Location
    Colorado Springs
    Posts
    51
    Thanks tinknocker!

    I had read up on flame rectification (cool stuff!) but had never seen any info on whether there were any special properties of the rod itself.

    If only igniters were as tough... that's the only other thing that has ever needed replacement on this furnace, which is understandable considering the environment they operate in.

    thanks again

  4. #4
    Join Date
    Feb 2006
    Posts
    362
    Steel wool is correct to use, not sandpaper, but to be honest with you I have never offered this to a customer. I am in the repair business, not in the "temporary" repair business and to protect myself from callbacks that I cannot charge back to someone - either customer or manufacturer, I will not just clean it up and hope it works.

    And to comment on what causes them to go bad, oxidation will form on them from the by-products of the fuel being burned and will start to crystalize from the heat sort of like glass which will block the proper flame rectification back to the control board. What i find really funny about flame sensors and thermocouples is that no one that I know of regularly practices sanding down thermocouples but will sand down flame sensors on a regular basis. Two different bi-metals in the thermocouple, not exactly the same as flame sensor but close enough.


  5. #5
    Join Date
    Nov 2004
    Location
    Colorado Springs
    Posts
    51
    Thanks precise!

    Sounds like the oxidation buildup and eventual no-op of the sensor is inevitable.

    I can appreciate your stance, as a businessman, on replacing rather than cleaning the sensor, but I'm curious -- are the sensors ever really bad if the deposits can be removed, the insulator is not cracked, and electrical continuity is still there? Are they good as new after cleaning, or will they re-oxidate faster than a new part? Or does the activity of removal, cleaning, and reinstalling the sensor weaken/degrade it, loosen bonded connections, etc., causing it to permanently fail? (that would concern me if I was the technician.)

    I'm not challenging you, I'm just wondering if next time mine gets dirty, I should insist the technician replaces it rather than cleaning it.


  6. #6
    Join Date
    Sep 2002
    Posts
    186
    If your combustion air comes from a laundry room or close to one .Quit using dryer sheets softner. they will coat a flame rod in no time.
    Because chicks dig it.

  7. #7
    Join Date
    Feb 2006
    Posts
    362
    I would think that it would weaken the sensor from its original state after you use steel wool on it. Not 100% sure on this but I am just using theory here. It makes sense to me that even more oxidation would occur once it is sanded due to more grooves in the rod to pick up more particles. That is my thoughts on it, but you should be ok by just sanding it down even though I wouldn't practice this unless it was 2:00 in the morning and my customer had no heat and I did not have a new sensor.

    One good thing about it is that it is an easy fix and if it goes down again you know exactly what to do

  8. #8
    Join Date
    Feb 2006
    Posts
    5
    The only flame sensors I clean are in older neighborhoods that still have old steel gas mains. The same furnace in newer subdivisions with plastic gas mains never quits because the flame sensor is dirty.

    Conclusion: The culprit is dirty natural gas.

    I have several LP furnaces in rural areas which flame sensors' never give me any problems.

    I have not seen where laundry rooms make a difference on flame sensor callbacks. HSI's definately, but not flame sensors. The only commonality between all of my FS callbacks is old steel gas mains.

  9. #9
    Join Date
    Nov 2000
    Location
    Memphis TN USA
    Posts
    6,969
    I clean every flame sensor on furnace maintenence agreement. On a breakdown, I usually try to sell them a flame sensor. Its only $50 difference and less chance of callbacks.

    I clean them with sandpaper. I figure if it is a solid rod why not do it the faster way.

    Note: Talked to a rep about flame sensors. He said voltage to flame sensor is not reliable becuase you need a true RMS meter. But he said any microamp reading at all says the flame sensor is good and its a bad board.
    If the superheat ain't right it ain't charged right.

  10. #10
    Join Date
    Apr 2004
    Posts
    7,680
    I've never seen a flame rod need replaced unless the procelin is cracked or the rod was burnt. Selling a replacement does not solve anything other than you have a new rod and a bigger bill.

  11. #11
    Join Date
    Nov 2000
    Location
    Memphis TN USA
    Posts
    6,969
    Its all about the warrenty.
    If you try to sell them a new one and they opt for a cleaning, the next call is billable.

    If the superheat ain't right it ain't charged right.

  12. #12
    Join Date
    Jan 2004
    Location
    PA
    Posts
    68,784
    Originally posted by docholiday
    I've never seen a flame rod need replaced unless the procelin is cracked or the rod was burnt. Selling a replacement does not solve anything other than you have a new rod and a bigger bill.
    You can bend the FS and it will still work, its just a piece of metal.

    OK, you shouldn't bend them.
    Contractor locator map

    How-to-apply-for-Professional

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

  13. #13
    Join Date
    Apr 2004
    Posts
    7,680
    You could probably rig a coat hanger to work. Yeah, dont bend them

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