reliance water heater pilot assembly 100109295 genuine original equipment manufacturer (oem) replacement part natural gas compatible with reliance, a.o. smith, and state branded tanks variety home supply ao smith replacement water heater pilot assembly. it is designed for natural gas and has a temperature setting of 190 degrees. the purpose of an ignitor is to ignite the gas after the gas valve opens up. it most cases, the ignitor turns off after ignition has occurred.