Forum Discussion

Bird_Freak's avatar
Bird_Freak
Explorer II
Aug 28, 2013

New Atwood furnace problem.

Ok guys here it is. I had a problem with furnace not staying lit and would lock out after third try. Board showed 3 flashing lights that said igniter. I pulled and cleaned igniter and wire connections with same results. I determined it must be board. Just for kicks I turned it on before ordering new board and it worked fine. Tried it the next morning and back to the same problem. Tried again that evening and worked fine. Same thing today. It is like me. Don't do mornings! Ideas?
Thanks for any help.

14 Replies

  • Bird_Freak's avatar
    Bird_Freak
    Explorer II
    Aug 29, 2013
    enblethen wrote:
    If you need to replace the circuit board, I would recommend replacing with a board from Dinosaur electronics.
    Dinosaur electronics
    That's who I was looking at. Thanks.
  • Bird_Freak's avatar
    Bird_Freak
    Explorer II
    Aug 29, 2013
    Some great info here. I pulled the electrode and checked with ohm meter and all looks good. Cleaned all connections, pulled screen out beside igniter and it was very dirty so I bead blasted that and cleaned up like new. Put everything back together and it worked tonight with a better exhaust output than it was. Now we will see in the morning. Nothing really left but the board I think.
  • mchero's avatar
    mchero
    Explorer
    Aug 29, 2013
    Thanks for the excellent post Chris! Very informative!

    Chris Bryant wrote:
    Heat really has nothing to do with the flame sensor- it uses ionization of the flame to pass a small current through the flame (it is just a "wire in the fire"). This current has to go through the ignitor cable and ignitor, then the flame to the ground, then back through the sheet metal to the ground connection to the board.
    Another failure that can happen in the ignitor is that the wire can become disconnected from the rod- the spark can easily jump a small gap, but the sensor current cannot.
  • enblethen's avatar
    enblethen
    Nomad
    Aug 29, 2013
    I say heat as the flame sensor must be directly in the flame to get the electrical signal.
  • Chris_Bryant's avatar
    Chris_Bryant
    Explorer II
    Aug 29, 2013
    Heat really has nothing to do with the flame sensor- it uses ionization of the flame to pass a small current through the flame (it is just a "wire in the fire"). This current has to go through the ignitor cable and ignitor, then the flame to the ground, then back through the sheet metal to the ground connection to the board.
    Another failure that can happen in the ignitor is that the wire can become disconnected from the rod- the spark can easily jump a small gap, but the sensor current cannot.
  • enblethen's avatar
    enblethen
    Nomad
    Aug 29, 2013
    That still could be the ignitor circuit as it has the flame sensor. If the flame sensor does not feel the heat it will shut the gas off.
  • Bird_Freak's avatar
    Bird_Freak
    Explorer II
    Aug 29, 2013
    enblethen wrote:
    Inspect it first!
    Look for cracks or chips in porcelain.
    Look closely at the wire from the ignitor board to the ignitor. Look for small black pin holes where it may have arced to ground.
    OK, I will check it but you do understand the furnace lights, it just shuts the gas valve off when the igniter stops the arc cycle.
  • enblethen's avatar
    enblethen
    Nomad
    Aug 28, 2013
    Inspect it first!
    Look for cracks or chips in porcelain.
    Look closely at the wire from the ignitor board to the ignitor. Look for small black pin holes where it may have arced to ground.

About Technical Issues

Having RV issues? Connect with others who have been in your shoes.24,348 PostsLatest Activity: Jan 13, 2026