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  1. #1

    Question PRO Question: Flame Sense rod

    Hi,
    I am an electrical engineer (new here, but not an idiot) that is adding a smart ignition/control/flame monitoring to a previously primitive (manual) burner type application. It involves adding a valve and controller with ignitor and flame sense rod. A few things came up with this.

    #1. As far as the controller goes, I am using the Honeywell S87 series, they make 2 different units: one is a single rod such as S87J1034 (one high voltage output terminal for combination flame sensing rod and ignitor), and the other type is a dual rod such as S87C/D series (separate connections for ignitor and flame sense rod). They make 2 "different" compatible ignitors for these, one is an Q347A series (which is just an ignitor electrode, designed to be used with a separate flame sensing rod), and the other is a Q347B series (this is a combo ignitor electrode and flame sensing rod in the same electrode, 1 wire connection).

    These controllers use a FLAME RECTIFIED type flame sensor rod, with approx 1.5uA threshold.

    1a. They say the Q347A is ONLY compatible with a dual rod system and controller, and the Q347B is a single rod COMBINATION ignitor/flame sensor in one rod unit.

    1b. The Q347B is discontinued, and honeywell has NO IDEA why they are still selling a single rod controller with no ignitor available for it (as per their tech dept).

    I would probably prefer to go single rod as the application is space constrained, and I may not have room for separate ignitor electrodes and flame sense rods in the burner. I have both controllers, the single rod one has no connection for a flame sense rod, just a single high voltage terminal for ignitor+sense. The dual rod controller has connections for ignition (hv) and sense (low voltage).



    #2. Now from what I gather, there is NOTHING special about a flame sense rod (other than the fact it is made of metal and can withstand immersion in flame), but so can any ignitor [I have heard of people using a screwdriver with a clip lead as a temporary flame sensor], so WHY can I not use their standard Q347A type ignitor, as a combo unit, and just leave out the flame sensing rod, I dont understand the difference.

    #3 Can flame sensor rods be bent/cut without functional ill effects (assuming I can do it without damaging the insulator)?? I have read lots of documentation that says don't bend the rods (but as far as I know they are just a solid piece of metal, no junction, no internals).

  2. #2
    Join Date
    Feb 2008
    Location
    Western NC
    Posts
    2,504
    This is not a DIY site. Read the rules.

    That fact that your an electrical engineer doesn't exclude you from the rules.
    I fully support the military and the War on Terrorism.


    If you don't know, then don't do. If you don't know and still do, then be prepared to pay someone else a lot to undo what you did and then do it right.

    If you do know, then do. But do it right. Otherwise, you may not be doing it long.

  3. #3
    Join Date
    Nov 2000
    Location
    Eastern PA
    Posts
    68,962
    Don't know why you feel the need to tell us you are an electrical engineer when the only professionals we will discuss such a situation with are HVAC professionals.

    This thread is way out of line for this open forum of this site and will not be discussed by any HVAC professional.

    Have you considered that you are altering an UL approved design and by doing so makes you completely responsible if there is a fire from this furnace?
    Government is a disease...
    ...masquerading as its own cure…
    Ecclesiastes 10:2 NIV


  4. #4

    Exclamation

    This is not a DIY post, and *please* stop cluttering the forum with flames when they are not relevent nor productive. I am a professional that works in a related industry that took on a special project for a customer that involves residential combustion products. Someone suggested that we talk to people who work with these products daily for some expert advice. We (possbily mistakenly) thought that this would be a good place to come for advice on equipment we normally don't deal with that many people here would have experience with. If this is truly some "sandbox" that we are not welcome in, that is fine, we thought this was a professionals helping professionals forum, and you could get off your soap box and show a little professional courtesy.

    Thanks

  5. #5
    Join Date
    Feb 2008
    Location
    Western NC
    Posts
    2,504
    Quote Originally Posted by illuzion View Post
    This is not a DIY post, and *please* stop cluttering the forum with flames when they are not relevent nor productive. I am a professional that works in a related industry that took on a special project for a customer that involves residential combustion products. Someone suggested that we talk to people who work with these products daily for some expert advice. We (possbily mistakenly) thought that this would be a good place to come for advice on equipment we normally don't deal with that many people here would have experience with. If this is truly some "sandbox" that we are not welcome in, that is fine, we thought this was a professionals helping professionals forum, and you could get off your soap box and show a little professional courtesy.

    Thanks

    Your gettin off on the wrong foot buddy. So you might want to watch your attitude. We are HVAC professionals that come to help others with general information. And to help other HVAC professionals with technical information.

    We are not here to take money out of our industry by informing all that come how to fix and install their own stuff.....that would be just stupid.


    We are professional and we have been sincere and curteous to you. Don't take it personal.



    And may last comment, if you don't know what you are doing, why don't you sub-contract it out to someone that does??? Its great that you wanna learn new stuff but to put lives at risk to do so is just plain ignorance....
    I fully support the military and the War on Terrorism.


    If you don't know, then don't do. If you don't know and still do, then be prepared to pay someone else a lot to undo what you did and then do it right.

    If you do know, then do. But do it right. Otherwise, you may not be doing it long.

  6. #6

    Smile

    All of our products go through regulatory approval by any governing bodies for markets in which they are used (UL, CGA, CE, etc).

    Quote Originally Posted by RoBoTeq View Post
    Have you considered that you are altering an UL approved design and by doing so makes you completely responsible if there is a fire from this furnace?

  7. #7
    Join Date
    Jun 2004
    Location
    Howell, Michigan
    Posts
    16,181

    Read the rules.

    This is not a DIY help forum.


    THREAD CLOSED!

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