Suburban furnace blower running constantly(cold)

Discussion in 'Miscellaneous Repairs & Maintenance' started by Jonson01, Jun 27, 2019.

  1. Jonson01

    Jonson01 Member

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    I had the camper unplugged most of the winter from the battery. Ended up replacing the battery earlier this year when I determined it was bad. When I plugged everything back in last week I heard the furnace running. So pulled the fuse on pos cable until I could get it popped up and investigate.

    Double checked and made sure thermostat was clicked off.

    The furnace just blows constantly as soon as it has power. I tried turning thermostat on to run a cycle, wouldn't ignite even after filling lines by igniting stove. My hvac buddy thinks it may be in a perpetual "cool down" mode. I plugged into shore power and let it run a long time but still persists. Another tidbit is when I have the fuse (at panel) pulled a red light lights up. Don't know if that means anything or not. I think that is everything I have thought of/tried so far. Any thoughts?

    received_433645487480225.jpeg received_343472179661162.jpeg received_2354679874747202.jpeg
     
  2. eoleson1

    eoleson1 Well-Known Member

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    I don't mean to be condescending, but does your t-stat have a separate switch for the fan? Mine does - Auto - Off - On
     
  3. Jonson01

    Jonson01 Member

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    I do not think so, I even had the cover off(stat) during troubleshooting and didn't see any other switches other that the slider for temp.

    This is what I have except brown or black. Screenshot_20190628-062813.png
     
  4. gladecreekwy

    gladecreekwy Well-Known Member

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    I’d replace the t stat first. Those are junk. Cheap easy upgrade
     
  5. Jonson01

    Jonson01 Member

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    Unhooking it should confirm that, right? Because I could try that.
     
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  6. tfischer

    tfischer Well-Known Member

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    Yeah your symptom is definitely not something a new stat will fix. You could unhook just to be sure.

    Also the red light on your converter just means a fuse is pulled or bad.
     
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  7. tfischer

    tfischer Well-Known Member

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    I agree with your HVAC buddy that it seems to be stuck in cool-down mode. Not sure how that works on these but there must be some sort of timing circuit... I know at least on mine if I turn it on and immediately turn it back off, even before it lights, it still runs for the same amount of time, so it has to be a timer and not an internal t-stat for cool-down mode.
     
  8. tfischer

    tfischer Well-Known Member

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    This is relevant:



    Guessing you need a new time delay relay.
     
  9. Jonson01

    Jonson01 Member

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    My friend and I did some exploratory surgery last night! Come to find out my model does not have the time delay relay. The module board was the other option/culprit according to the manual I found online. Sure enough we would tap on a particular part on the board and get it to shut off after the 90sec cool down window was over. The new(upgraded) part is $81 on amazon. Glad it is not needed right now, but will need it later in the year!

    Thank you all for your help.


    P.S

    Again another tidbit about the converter/fuse: With the blower on the furnace drawing power and pulled 15amp fuse at converter, it would sound a beep for a sec and quit with a low groan(like a low battery on a toy) and the light would come on. But with the blower completely off and not drawing it would continue to beep and not quit. Just seemed odd that the blower drawing power or not would make that difference.
     
  10. Jonson01

    Jonson01 Member

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    Update:

    Over the long weekend went camping and changed the control board(this particular model doesnt have a time relay or at least not a separate part from the control board) and that was the fix. Furnace is in and ready for cooler camping. Thanx to everyone for your input!!
     
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