NPS40 stops running after approximately 10mins after getting up to temp

verbage65 Posted By verbage65, Feb 13, 2013 at 2:51 PM

  1. verbage65

    verbage65
    New Member

    Feb 7, 2013
    3
    0
    Hi all,
    Hope you can help.I just recently cleaned the exhaust blower (installed new gasket) and the surrounding structures.Nothing was exceptionally dirty.After cleaning the stove comes up to temp but once there I will hear a mechanical "click" then about 10mins later the stove shuts down.Any ideas would be appreciated.

    Thanks!
     
  2. SmokeyTheBear

    SmokeyTheBear
    Minister of Fire

    Nov 10, 2008
    13,363
    1,662
    Loc:
    Standish, ME
    Check your low limit switch, it maybe dirty or worse.
     
  3. verbage65

    verbage65
    New Member

    Feb 7, 2013
    3
    0
    Hi Smokey,
    Thanks will do it should read open right ?
     
  4. SmokeyTheBear

    SmokeyTheBear
    Minister of Fire

    Nov 10, 2008
    13,363
    1,662
    Loc:
    Standish, ME
    When cold, then apply some heat and it should read closed.

    I don't know about the NPS40 Low limit but I personally prefer a ceramic one, the "plastic" like ones are subject to deformation and false opening when heated.

    You might need to clean the switch or the location behind where it attaches of ash build up.
     
  5. verbage65

    verbage65
    New Member

    Feb 7, 2013
    3
    0
    Hi Sm
    okey,

    Hi Smokey,
    So just an update.I Ohmed out the low limit switch and it was open until I heated it then it closed.It appeared fine so I went looking elsewhere for the issue.I checked the ignition switch and when I went to pull the connection the device broke off in my hand so it was "cooked".I replaced it and still has the same issue so I jumped the low limit switch after the fire got going and it fixed the issue so I replaced the low limit switch and the issue is now resolved.I suspect the low limit switch must have worn out over the years and became less sensitive to the 140 degree threshold and thus the issue.Thanks for the assist!
     

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