Dead furnace humidifier

Discussion in 'Non-Automotive Stuff' started by Clark, Nov 26, 2019.

  1. Clark

    Clark In Maximum Overdrive

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    So the furnace Skuttle humidifier is bone dry. I assumed the solenoid water valve was done after 18 years as was the sister-in-laws which I fixed.

    When replacing the solenoid valve I checked the 24V power to the solenoid with the furnace running and - nope - no power. There is water but no power.

    Dismantling reveals that the 24V comes off the Heil furnace circuit board - $150 for the replacement board.

    Anyone else experience this? I'm not looking forward to replacing that $150 board. I could install a sail switch and and external 24V power supply for considerably less but this is a p*sser.
     
  2. Rancherous

    Rancherous Administrator Staff Member

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    So Clark we wire them off of the furnace EAC Electronic Air Control circuit of the furnace. Most times the EAC is 120V so we add a 24v step down transformer, so when blower motor starts the solenoid opens. Is this the way yours is wired? It will be labeled EAC with terminals on the Heil board.
     
    Last edited: Nov 26, 2019
  3. Clark

    Clark In Maximum Overdrive

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    Thanks Rancherous. There is no separate 24V step down transformer so that must be built into the board. I will look for an EAC label on the board. My one concern is that if the 24V circuit failed, will the board fail in some other manner - at the worst time such as right now in the Denver Metro area.
     
  4. ForistellFord

    ForistellFord In Maximum Overdrive GOLD MEMBER

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    You could tap off the line to the step down and add an external one, but you pointed out the big problem there. Can you confidently trust that repairing that component will rectify the issue in the long term? Ounce of prevention and all that... I'd replace the board but that's me.
     
  5. Rancherous

    Rancherous Administrator Staff Member

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    How old is the furnace? Don't see a ton of board failures but they do happen. So I guess its up to you on replacement, Look for that EAC and buy cheap 120 to 24V step down if EAC is present. Heil may have the 24V HUM connection and that may have failed, most components on those boards are independent so you may still get a long time from the board. We do a lot of York, Rheem and Trane and they all have the EAC terminals but Heil may not.
     
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  6. Clark

    Clark In Maximum Overdrive

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    Location:
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    Checked the danged humidifier yesterday and it's wet like it should be! How is beyond me. I would have thought anytime the furnace is running there should be 24V power to the humidifier - and there wasn't when I replaced the solenoid valve.
     
  7. Rancherous

    Rancherous Administrator Staff Member

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    Location:
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    You will only get 24v power on a heat call, if its wired into the HUM terminal, once burner goes out power is off.
     

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