Enviro Maxx overheating

stecy Posted By stecy, Nov 24, 2017 at 11:17 AM

  1. stecy

    stecy
    Member 2.
    NULL
    

    Dec 4, 2007
    36
    0
    Loc:
    Southern VT
    Ten year old Enviro Maxx. Had various issues, usually POF sensor failing. This time the Hi-limit sensor opened, stove was very hot. First time that this ever happened. Let it cool, turned it off, waited a few minutes and turned it on again. Pellet auger ran continuously - that would certainly cause overheating. Seemed that the control board might have failed. Left the stove off for 24 hrs. Then tried it again, now runs normally. So could this be a one time thing? Replacement control board and membrane $450. Don't want to spend that $$$ if not needed, but also don't want to live with the prospect of a shutdown from overfiring occurring at any time. Especially as we get into the coldest months and there is no other heat source in that part of the house.
     
  2. bob bare

    bob bare
    Minister of Fire 2.
    NULL
    

    Oct 31, 2013
    2,041
    353
    Loc:
    park county montana
    Well,I have spare controls for both my units.10 years,I would really think about spare control.
     
  3. VTrider

    VTrider
    Member 2.
    NULL
    

    Nov 10, 2007
    229
    21
    Loc:
    Northern New England Burlington Vermont
    I'm a Maxx owner - 7 years. I've had my fair share of various / normal stove issues - all of which I've successfully resolved with the help of this great community.

    Do you know if your convection/room blower fan was running when your stove overheated and tripped the Hi-limit sensor? I had a very similar problem like you which was related to the POF sensor and a continuously running auger - If I hadn't corrected it, i'm sure my stove would've eventually tripped the Hi-limit sensor as well.

    When initially started, the Maxx unit (as well as most other stoves i'm guessing) goes through an automatic, preset program which is directed by the control board, much like the BIOS startup on a computer. Its like overdrive...ignitor blazing away, auger spinning on steroids, exhaust fan on full, etc. Once this sequence ends (in about 10 minutes on the Maxx) it checks if the POF sensor has closed, indicating an adequate fire in the burn pot - at which point the convection fan starts up and the stove goes into whichever preset program (auto on/off, hi-low, manual) which is set on the control board.

    As you probably know already, if the POF sensor remains open - the stove shuts down and you get that flashing #3 light, like if you forgot to fill the hopper with pellets. Well, in my case the POF sensor failed to close, yet my stove instead of initiating the shut-down procedure - remained 'stuck' in the startup sequence. So basically, the stove was in full throttle with no convection fan to move the heat out. This happened to me sporadically 4 or 5 times, I eventually replaced the motherboard which did not help. This situation i'm sure would eventually lead to an over-fire / hi-limit scenario in which the stove would then power down (hopefully) - luckily for me, I just happened to be home everytime this happened and manually shut it off.

    I never replaced the POF sensor (which in retrospect, would've been a lot cheaper than a control board), but upon inspection - I did noticed that a hard, crusty layer of carbon would build up on it, I believe this insulated the sensor leading to some mixed signals to the control board? I now periodically remove it and wipe away the build up (5 minute procedure) - I've never had this problem since.
     
  4. reg1952

    reg1952
    Member 2.
    NULL
    

    Sep 5, 2012
    59
    14
    Loc:
    Guelph Ont.
    My Maxx is 5 years old. On my third board. First one fired from lightning. Took out more than just my stove. Second one lasted 2 years and ever since that board was installed the stove would go into a melt down spasm and would just keep dumping pellets causing it to overheat. Luckly I just happened to be home when it happened. Then for what ever reason that board quit. I installed another board and it has never happened since. I believe in jinks so now I have to go check my stove and see if it ok because I just talked about it.lol
     
    bob bare likes this.
  5. bob bare

    bob bare
    Minister of Fire 2.
    NULL
    

    Oct 31, 2013
    2,041
    353
    Loc:
    park county montana
    Best wishes.Appears in the stove industry,weak electronics are never recalled,like autos.
     

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