Natural Gas Furnace - no heat

Discussion in 'HVAC' started by madrussian, Dec 20, 2016.

  1. Dec 22, 2016 #21

    nealtw

    nealtw

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    That could be a problem.:)
     
  2. Dec 22, 2016 #22

    kok328

    kok328

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    Check around on the transformer. Sometimes they have a manual overload reset button on them.
    Leave your meter on the hsi wires or at board during ignition and see if it ever gets that far.
    Are you still showing 3 blinks?
     
  3. Dec 22, 2016 #23

    kok328

    kok328

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    If you do replace the transformer put an inline fuse on the secondary.
    Short in the system may have burned it up.
     
  4. Dec 24, 2016 #24

    Jeffh

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    Does the hsi glow red hot during the operation? That should happen next. Then, gas valve clicks open, flame sensor keeps gas valve open, low limit initializes, blower kicks on...
     
  5. Dec 26, 2016 #25

    madrussian

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    It was the transformer. As soon as it was replaced, turned the system on, the HSI got red hot and gas flowed.
     
    oldognewtrick and nealtw like this.
  6. Dec 26, 2016 #26

    oldognewtrick

    oldognewtrick

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    We love happy endings.
     
  7. Dec 27, 2016 #27

    madrussian

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    I actually stumbled across the fix. When schematic was reading 24V, I was measuring in DC, not AC. Doh.

    the flow chart led me to replace the xformer but I dont think it was the 24v side, I think the 120V side wasn't completely operational.
     
  8. Dec 27, 2016 #28

    nealtw

    nealtw

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    You must of had 120 volts on that side and that is really all you can check on that side. After that anything that prevents you from getting 24 volts is the problem with the transformer.
     

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