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WM 97+ flame signal

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heidleml
heidleml Member Posts: 34
We have a WM 97+ that was shutting down after 5-10 seconds of successful ignition. Tech called WM tech support and they had us replace ignitor, spark wire and control board. Still having the same result. Tech onsite now and has verified proper grounding, condensate components are free of obstructions etc., etc. My guy is a really good tech and at his wits end. Anyone have any pointers?

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  • pedmec
    pedmec Member Posts: 994
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    are you getting the proper flame signal and then its jumping out? you should be able to see the flame signal on the screen
  • HVACNUT
    HVACNUT Member Posts: 5,870
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    Assuming its showing an ignition fault. 
    Is this a new installation or it's been online and this is a new issue?
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,153
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    How old is the boiler? Is there a blockage in the exhaust vent. Possible condensation build up because the vent is not properly supported causing a low spot for water to collect. To test this disconnect the vent pipe and operate with vent disconnected. DON'T LEAVE IT THIS WAY. THIS IS ONLY FOR A TEST OF ABOUT 2 TO 5 MINUTES OF FLAME TIME with windows and doors open for ventilation.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • heidleml
    heidleml Member Posts: 34
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    @HVACNUT boiler has been in service for several years with no issues. We performed the complete maintenance on it and this is when it started having problems. Combustion analysis was performed and right in spec. Gas pressure in spec.

    @pedmec WM suggested the control, ignition cable and ignitor because the signal was hovering at 50. My guy is currently trying to get it to stay on long enough to see the signal.
  • heidleml
    heidleml Member Posts: 34
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    @pedmec This is after the recommended components were replaced.
  • pedmec
    pedmec Member Posts: 994
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    is an error code showing up?
  • skiereric
    skiereric Member Posts: 66
    edited November 2022
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    Fellow WM97+ owner here.
    There is a service bulletin that might be the cause of this problem - https://www.weil-mclain.com/download/file/fid/3021

    I would try seeing if switching from 155 to 110, if that solves the problem then you need to replace the gasket per the service bulletin.

    If that does not work, I would adjust the minimum fire rate, and see if bringing it up to 2100 fixes it.

    I had this exact issue, and adjusting the fire rate fixed it.

    Before, it would take dozens of attempts to fully ignite as when the flame signal is

    Alan (California Radiant) Forbes
  • skiereric
    skiereric Member Posts: 66
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    And ouch, replacing the control board $$$ ...love this method of diagnosis. Out of curiosity, does the homeowner have to eat that expense? The contractor? Or can you return the part?

    As a homeowner, I would be livid if you were asking me to pay.
  • pedmec
    pedmec Member Posts: 994
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    Electronic components are not returnable, at least at my suppliers. That's why you need to be a good troubleshooter and not a parts changer.
    skiereric