Rinnai Spark Kit for 26iV & HD50i – Genuine Replacement The Rinnai Spark Kit - it's the real deal for the 26iV and HD50i water heaters. This is a top-notch ignition component its sole job : to light the spark that gets your burner firing every time the hot water tap is turned on. And its crucial because this is part of the electronic ignition system that makes sure everything runs smoothly without any hassle. When you turn on a tap to get some hot water - the heater automatically fires up the electronic ignition and lights the burner. But the spark kit does all the heavy lifting - generating the high-voltage spark that actually gets the gas going in the first place. And because of this - the system can deliver hot water on tap all the time, no problem. But things get a bit tricky if the spark or ignition bits go bad - y