Burner ignition leads connect the Electrode to the Ignition transformer, they are usually made from HT cable which has a silicone sheath and high-temperature resistance. HT Leads can fracture internally and inhibit the transfer of current to the spark electrode resulting in a weaker spark, or intermittent issues with start-up.

It is recommended that the spark electrode leads are replaced every time your burner is serviced to ensure reliable operation, the timing of this depends on the burner duty cycle and the frequency at which the burner is started. The environment that the burner is in can also affect the replacement intervals.