Hayward H-Series H250ED2C Expert Line Natural Gas 250K BTU Cupro Nickel Digital Pool Heater. Hayward H-Series Electronic heaters deliver exceptional performance and economy. An electronic ignition system ensures reliable lighting, and - like all H-Series heaters - they feature a Cupro Nickel Finn Plate heat exchanger and Fire Tile combustion chamber. An easy-to-read LED control panel provides digital temperature readout and diagnostics for quick identification of components that might need service.