That could be a symptom of the control board, or the ignitor, or a wiring failure (assuming it had worked). Look for obvious things like a loose or corroded, or broken wire to the ignitor. Watch the thing through a full cycle to verify it never gets hot. It doesn't stay hot once the system determines it has actually lit the burner. On some, the ignitor is also the flame detector. If it does get hot, when the gas should then come on, if it doesn't detect that it actually got hot because of the flame, rather than applying electricity to make it glow, it will shut the gas off. So, if it does come on, it could be the gas valve is not opening. This again, could be the valve or the controller. If you are comfortable with a meter, you can verify that the parts are getting their proper voltages at the proper time. Also, if this is a closed combustion device, the fan may not have come on and the vacuum switch interlock may be preventing it from going through the proper cycle since it is sensing some problem with the flue.