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Solved Thermal Runaway, never seen this problem before. (R1 Plus)

Discussion in 'Troubleshooting' started by erer1243, Mar 26, 2017.

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  1. erer1243

    erer1243 Member

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    Hi, fun to be back on the forums, though unfortunately with a problem. Starting yesterday, on all my prints, at about 5 to 10 minutes in there is a quick dip in temperature and it halts for thermal runaway. It always looks exactly the same on the temperature graphs. Not just a quick dip, but the exact quick dip every time. Check the screenshot of octoprint temp graph and see the actual dip recorded. Ignore from -9 mins and prior, the target temp line is wrong. This is a problem I have when octoprint has an unhandled error. The print actually started at about -9-7 mins. I have dual fans on my printer but otherwise everything is stock. The dual fans have been on for months, but this problem is very new. I'm at a loss here and prior forum threads I read about thermal runaway seem irrelevant to my problem. Thanks in advance.
     

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  2. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    More likely a loose thermistor or a flaky thermistor or a bad connection to the thermistor.

    When it starts moving around it jostles itself...
     
  3. erer1243

    erer1243 Member

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    The thermistor is in place and the wires look good. I don't know what you mean by flaky.
     
  4. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    I mean it is intermittent. try heating up the hotend, watching the temperature graph and move the X platform around and wiggle the wires.

    If the thermistor is cracked or the wires to it have a bad solder joint then moving things around would make the readings go to crap.
     
  5. erer1243

    erer1243 Member

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    I just cleaned the head and reseated all the connectors that ride around on the carriage. I don't know exactly how to test this without just wasting 10 minutes of printing, but at the moment (just like previously) everything seems to be working 100% fine.
     
  6. erer1243

    erer1243 Member

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    Alright I will try that.
     
  7. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    You are going to have to either make assumptions or do the testing :)
    You can rest assured that something is wrong with the thermistor circuit or the temperature would stay steady.
    All you can do is isolate what it wrong.
     
  8. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    The R1+ at least has a cartridge style thermistor that is firmly mounted into the heater block so "loose" is not likely the issue with the thermistor itself. However internally it could be cracked or loose wire connections will bite you as well.
     
  9. erer1243

    erer1243 Member

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    I don't think the problem is wiring. When the wire is disconnected, it immediately pushes a mintemp error and halts, not thermal runaway. If the wire got jostled in the middle of a print, I believe this is what would happen. You might be right, its broken inside, because I don't know what sort of symptoms that would entail. I've been jiggling the wire and carriage as well as trying random g1 movements at different speeds. I can't get it to give any sort of error. It heats consistently and stays there.
     
  10. erer1243

    erer1243 Member

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    I think I might've just found the problem. When the fans switch from 100% (what they always start the print at) to 255% speed, the temperature dips. When they switch off, it also continues compensating for them even though they're not blowing. I wonder why this is happening now and never has before. I guess I have to change the maximum differential in the firmware or something. I think one of the old forum posts is about that, so I'll go look for that.
     

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  11. mark tomlinson

    mark tomlinson ༼ つ ◕_ ◕ ༽つ
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    A larger heater core (40w) would help if you still have the stock one (30w) or the one with the E3D (25w).

    They are very cheap.
     
  12. erer1243

    erer1243 Member

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    If there's no actual problem then I probably won't spend any money. It seems to just be a pid setting issue. Don't know why it happened but after some adjustments and manually stepping up the fan to full speed in increments, the printer is doing fine.
     
  13. erer1243

    erer1243 Member

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    Got it working by doing some PID tuning. Mysterious that it just appeared as a problem, but it's fixed now.
     
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