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Furnace Help

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mbinder
mbinder Member Posts: 6
in Gas Heating
Hello, I’ve got an Airtemp furnace that is just cycling. I see the igniter turn on after a click from the board, then nothing else. I think there usually would be another click when the gas valve opens, but that’s not happening. Not sure if that’s the problem, or if there is something else causing it. Any help or suggestions would be greatly appreciated!

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  • Big Ed_4
    Big Ed_4 Member Posts: 2,785
    edited March 2023
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    We would need to know if there is voltage going to the gas valve during the cycle ..

    There was an error rendering this rich post.

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,859
    edited March 2023
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    @mbinder... There are so many reasons for that. It could be that the control board (usually called a fan timer) is defective. But more likely there is a sensor or other item that is connected to the board that is not doing its job correctly.

    OR

    It is doing it's job and the reason for the failure to light must be fixed; like a blocked vent switch may not allow the gas valve to open until the thing that is blocking the vent is removed

    What model number is your AirTemp?
    This way I can look up what control comes with that furnace and see what the trouble shooting guide says the cause might be.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • mbinder
    mbinder Member Posts: 6
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    @EdTheHeaterMan It’s VG7SA 072C-24B1. Outside says Airtemp, inside the door says Nordyne. Thanks!
  • mbinder
    mbinder Member Posts: 6
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    Big Ed_4 said:
    We would need to know if there is voltage going to the gas valve during the cycle ..
    Checked this and there’s 24v from the board to the gas valve
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,859
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    It appears that your Fan timer control has 3 LED lights, a Green, a Red, and a Yellow. Is there a way to see those lights when the problem is happening?

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • mbinder
    mbinder Member Posts: 6
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    EdTheHeaterMan said:
    It appears that your Fan timer control has 3 LED lights, a Green, a Red, and a Yellow. Is there a way to see those lights when the problem is happening?
    Green and red are solid the entire time. No flashing lights and orange/yellow light never comes on.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,859
    edited March 2023
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    The yellow is Proof of Flame.

    Nothing flashing on the Red or Green. There is a solder connection on the under side of your fan timer that has eroded away. The wire that goes to MV on the gas valve comes from the 12 pin connector. One of those 2 yellow wires is not making contact. If you are handy with a soldering iron and you are comfortable with taking the Fan Timer board off the furnace, I bet you will find a bad connection on the 12 pin socket attached to that board.

    If you are not a DIY then you need a pro to replace the fan timer. It will be pricey

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,859
    edited March 2023
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    The first thing you want to do is to make sure the yellow wires from the 9 pin connector are connected to the board and the gas valve.
    With the power off
    1. To do this you pinch the clip in the 12 pin connector and remove the plug. Then plug it back in
    2. Then look at the yellow wires on the actual gas valve that is on the gas pipe. See that the connection to the gas valve is good.
    3. Then turn the power on and try the heater again.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • mbinder
    mbinder Member Posts: 6
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    EdTheHeaterMan said:
    The first thing you want to do is to make sure the yellow wires from the 9 pin connector are connected to the board and the gas valve. With the power of 1. To do this you pinch the clip in the 12 pin connector and remove the plug. Then plug it back in 2. Then look at the yellow wires on the actual gas valve that is on the gas pipe. See that the connection to the gas valve is good. 3. Then turn the power on and try the heater again.
    Tried this. Nothing different. Still have power from board to gas valve, just seems solenoid isn’t firing. Seems like a bad gas valve?
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,859
    edited March 2023
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    mbinder said:


    Tried this. Nothing different. Still have power from board to gas valve, just seems solenoid isn’t firing. Seems like a bad gas valve?


    As long as you are sure that the gas valve is getting 24 volts and not opening then you have the correct diagnosis. How did you verify the valve did not open with 24 V power to it? with an electric multi meter set to read AC volts?

    The other way is to take 24 volts directly from a transformer and apply it to the valve terminals. When 24 Volts is present the valve should open.

    And finally the real stupid question. Is there an on/off switch on the gas valve? Is it set to ON?

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • mbinder
    mbinder Member Posts: 6
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    EdTheHeaterMan said:
    Tried this. Nothing different. Still have power from board to gas valve, just seems solenoid isn’t firing. Seems like a bad gas valve?
    As long as you are sure that the gas valve is getting 24 volts and not opening then you have the correct diagnosis. How did you verify the valve did not open with 24 V power to it? with an electric multi meter set to read AC volts? The other way is to take 24 volts directly from a transformer and apply it to the valve terminals. When 24 Volts is present the valve should open. And finally the real stupid question. Is there an on/off switch on the gas valve? Is it set to ON?
    Yeah it’s set to On. Tested the power from the board to the gas valve connections with a multimeter and it read 24v
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,859
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    Have you replaced the gas valve yet?

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

  • mattmia2
    mattmia2 Member Posts: 9,672
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    You did check the pressure to the gas valve, right?

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