I'm pretty sure that the 80mgf has whats called a hot surface ignitor. It glows red hot and directly ignites the gas. These do break on occasion. If I am wrong and it is a spark, listen to it as it tries to light. If it makes no sound then the spark igniter is defective. if it does spark and light up but then goes off it might be the flame sensor needs to be cleaned off. Either way it is not something you should play around with yourself. Gas is very dangerous stuff and if you screw up you could blow your house up. That's why there are professionals.