Spark electrode has 2 functions
1) to ignite the main flame
2) PROVE main flame lit
Main flame generates a milivolt signal via flame ionization. This signal goes back to circuit board to PROVE main flame lit (all's OK...no raw fuel)
If electrode is dirty....signal can't be transmitted
If electrode out of position (engulfed in flame)----no signal
If electrode ceramic is cracked...signal goes to ground
If electrode high tension wire loose/dirty...no signal
Remember it is just a milivolt and doesn't take much resistance etc to stop it from getting back to circuit board
Lights flickering when spark electrode firing.......
Low DC Voltage or voltage interrupted
On battery power...check battery voltage
On shore power....check converter DC output (S/B 13.2V Minimum)