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  1. #1
    Join Date
    Nov 2005
    Posts
    367

    nordyne tripping limit

    model m3rl080a
    ser m3a050301139

    keeps tripping limit on combustion blower
    work alright while i there
    something over heating but what
    any help?

  2. #2
    Join Date
    Jul 2009
    Location
    Columbia, MD
    Posts
    3,855
    is this a 90%?

  3. #3
    Join Date
    Jul 2007
    Location
    Virginia
    Posts
    5,531
    Quote Originally Posted by iowa tech View Post
    model m3rl080a
    ser m3a050301139

    keeps tripping limit on combustion blower
    work alright while i there
    something over heating but what
    any help?
    I would first pull the inducer motor off and check to see if the restrictor plate (inducer orifice as they call it) is damaged, eaten away, or has fallen out.

    If the inducer is pulling too much flue gas through the orifice, the gas is not having enough time to cool off by staying in the HX long enough.

    You can also put a temp probe in to see if the flue temp is above 145f to eliminate the possibility of a bad switch.

    The part number for the orifice on the 80,000 btu unit is #155315R.
    Instead of learning the tricks of the trade, learn the trade.

  4. #4
    Join Date
    Nov 2005
    Posts
    367
    Temp is about 135 in flue
    New c blower install by first tech
    Yes 90%

  5. #5
    Join Date
    Jul 2007
    Location
    Virginia
    Posts
    5,531
    Quote Originally Posted by iowa tech View Post
    Temp is about 135 in flue
    135f flue temp is tripping a 145 limit.

    How far away from the inducer did you measure the temp?

    Assuming you are confident of your temp reading, and the 135f flue temp is stable, I would be installing a new limit.

    A combustion analysis would help in determining if the readings are stable.
    Instead of learning the tricks of the trade, learn the trade.

  6. #6
    Join Date
    Dec 2011
    Location
    somewhere between here and there
    Posts
    478
    i remember my first time with a problem similar....the disc was so rotten that it wasnt there. i was pulling my hair outa head untill some other guy said that the opening should be 1.5 inches.....i said its about 3.... disc wasnt even there or any signs of it...hahahaha

    couple months later i go to similar call....new apprentice was like omg u so smart...lol i told him the long version....he laughed....


    Please, Please Please......keep the Factory Smoke in the Wires!!!!!


    Is it Rum'Oclock yet???

  7. #7
    Join Date
    Jul 2009
    Location
    Columbia, MD
    Posts
    3,855
    135* flue temp.

    combustion analysis would help determine whats going on. 135* is max you want on a 90% furn

    check air supply blower wheel and secondary heat exchanger. Make sure your moving enough return air. usually low airflow or overfired causes flue temp to be that high.

    you need 150cfm per 10,000 input btu with 90% furnace.

  8. #8
    Join Date
    Feb 2010
    Location
    In a boiler room
    Posts
    7,073
    Quote Originally Posted by BigBacardi View Post
    i remember my first time with a problem similar....the disc was so rotten that it wasnt there. i was pulling my hair outa head untill some other guy said that the opening should be 1.5 inches.....i said its about 3.... disc wasnt even there or any signs of it...hahahaha

    couple months later i go to similar call....new apprentice was like omg u so smart...lol i told him the long version....he laughed....
    I find a lot of these m3 furnaces with inducer limit tripped. To date, every one was due to corroded or missing orifice.

  9. #9
    Join Date
    May 2012
    Location
    Upper Michigan
    Posts
    3,588
    Quote Originally Posted by chuckcrj View Post
    I find a lot of these m3 furnaces with inducer limit tripped. To date, every one was due to corroded or missing orifice.
    Invaluable information, thanks, hear of this one time only but the other tech never found the issue that I know of.

  10. #10
    Join Date
    Jan 2011
    Location
    Ottawa, Canada
    Posts
    383
    Orifice.. one for the memory banks...

    Sent from my SGH-I747M using Tapatalk 2

  11. #11
    Join Date
    May 2012
    Location
    Upper Michigan
    Posts
    3,588
    The older Lennox ghr 26 had them also.

  12. #12
    Join Date
    Feb 2010
    Location
    In a boiler room
    Posts
    7,073
    Quote Originally Posted by Joehvac25 View Post
    The older Lennox ghr 26 had them also.
    Yes. Did you ever see one of those corroded? They obviously used better material.

  13. #13
    Join Date
    May 2012
    Location
    Upper Michigan
    Posts
    3,588
    Quote Originally Posted by chuckcrj View Post
    Yes. Did you ever see one of those corroded? They obviously used better material.
    No but I have seen the condensate box come apart and not close ps switch. Inside of it i mean. The old discs always seem fine in the inducer!

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