The flame roll-out switch is located on a Carrier furnace.

The electrical characteristic of a flame is mimicked by this board.It is important to detect when the gas furnace is producing a flame.If the gas valve is open but there is no flame, gas will continue to flow and build up, and if it finds an ignition source, it may explode.The flame detection system is the most common problem with gas furnaces.Sometimes the flame rod needs to be cleaned because it has become dirty.The wire going to the flame rod can be a problem.The other wires are usually bundled with this wire.The small signal produced by the flame rod can be overwhelmed by this.Ground and Neutral are not connected.This is required in order for the system to work.It is barbaric but I did not design it.Ground and Neutral can only be connected at the service entrance to the building and no place else.Even though there is no problem in the furnace itself, an electrical connection problem outside the service entrance may cause the flame sensor circuit to malfunction.The furnace control board is expensive to replace.The electrical characteristics of the flame are mimicked by this board.You connect the hot wire to the control board instead of the flame rod.The cabinet ground/combustion burner ground is connected to the Ground wire.The control board signal ground might not be the real ground.If the furnace control board recognizes a valid flame then the problem is not with the board.There is a warning.The un-isolated Mains will be on this board.1.It should be in an insulated box.An electrical box works well.Put something under the box to protect it.I haven't done that yet.You can make the wires longer.2.This device is not used for fun.It is only used by experienced technicians.You can kill yourself and other people if you don't know what you're doing.As soon as you see the flame, turn the switch on.Do not turn it on if there is no flame.Don't use it to make the furnace run with a bad system.If you leave the furnace running after you get it to run, the flame will go out and the gas valve will remain open, killing everyone.If the control boards detect a flame before the gas valve is open, they should refuse to start the turn-on cycle.The D1 Diode 1N4007 R1 2.2M Resistor is one of the parts listed.I tried to make this safe.You must use the project at your own risk.Ok?If you're interested in learning more about gas furnaces, you can read my article What I Have Learned About Propane Furnaces (The Hard Way) or The Mystery of the Flakey Furnace at www.jmargolin.com/furnace/index.htm.There is a person named JM.

The electrical characteristic of a flame is mimicked by this board.

It is important to detect when the gas furnace is producing a flame.If the gas valve is open but there is no flame, gas will continue to flow and build up, and if it finds an ignition source, it may explode.The flame detection system is the most common problem with gas furnaces.

Sometimes the flame rod needs to be cleaned because it has become dirty.The wire going to the flame rod can be a problem.The other wires are usually bundled with this wire.The small signal produced by the flame rod can be overwhelmed by this.Ground and Neutral are not connected.This is required in order for the system to work.It is barbaric but I did not design it.Ground and Neutral can only be connected at the service entrance to the building and no place else.Even though there is no problem in the furnace itself, an electrical connection problem outside the service entrance may cause the flame sensor circuit to malfunction.

The electrical characteristics of the flame are mimicked by this board.You connect the hot wire to the control board instead of the flame rod.The cabinet ground/combustion burner ground is connected to the Ground wire.The control board signal ground might not be the real ground.If the furnace control board recognizes a valid flame then the problem is not with the board.

1.It should be in an insulated box.An electrical box works well.Put something under the box to protect it.I haven't done that yet.You can make the wires longer.

2.This device is not used for fun.It is only used by experienced technicians.You can kill yourself and other people if you don't know what you're doing.

Don't use it to make the furnace run with a bad system.If you leave the furnace running after you get it to run, the flame will go out and the gas valve will remain open, killing everyone.

If the control boards detect a flame before the gas valve is open, they should refuse to start the turn-on cycle.

I tried to make this safe.You must use the project at your own risk.Ok?Say "Ok"

If you would like to learn more about gas furnaces, you can read my article What I Have Learned About Propane Furnaces (The Hard Way) or The Mystery of the Flakey Furnace at www.jmargolin.com/furnace/index.htm.