I have been igniting manually with a lighter. I turn up the thermostat, turn the gas switch on, and turn the electricity on to the unit. I listen for the gas to cycle on and light it. This works but, I would like to see if I can fix the problem. Any information on how to begin fixing this problem would be much appreciated. Thanks.

There is no ignition you need to post more info:if its gnition off the control board you can put a universal ignition starter on and wire it one side on common and the other side on w terminal or tap into gas valve wires so when gas valve energizes it make the ignition also. Mikie D

Do NOT do what the poster named Mikie D said. You will compromise the safety of your furnace and this can create VERY SERIOUS HAZZARD.

According to your model your system is a 90%+ style furnace and the ignition system and control circuit board should NEVER be compromised.

You probably have a defective HSI (hot surface igniter) or a defective circuit board.

By adding in a separate non compliance ignition system you take the chance of having one big explosion since the system control board is not designed to work correctly with a add on style spark box.

I agree with hvac1000. Check to see if the ignitor is cracked or any defects, if so replace it. Check to see if you are getting power to the ignitor. Unplug the ignitor and connect a volt meter to the furnace ignitor plug. Turn on the furnace and wait for the startup sequence. Within a couple seconds after you hear the gas valve turn on you should be getting the required voltage (110v or 24vac not sure which one). If you have no voltage that means you have a bad board, if you do then replace the ignitor.
P/N B1401015S

Xx

Xx