If your igniter is getting hot but mot igniting, make sure the damper below the burnpot is closed. If you are experiencing longer than usual ignition times consider replacing your door gasket.
If your igniter is not getting warm, your igniter has most likely failed and should be replaced.
Often, when igniter fails, the ignition fuse inside of the controller blows and should be inspected and replaced if necessary. These models have isolated fuses for each circuit. The ignition circuit should be in position 1. This is a 5 AMP, 125V rate fuse, click here to see the fuse.