Zodiac R0457500 Hot Surface Ignitor Replacement for Zodiac Jandy LXi Low NOx Pool and Spa Heaters. Hot surface ignitor replacement. Fits Zodiac Jandy LXi Low NOx pool and spa heater models 250, 300, 400. It is a “glow bar” type silicon carbide unit. It is energized whenever there is a call for heat and the red igniter light on the boiler control is lit. The igniter functions as a flame sensor for the boiler control.