The Acutemp CN series tankless water heaters from Keltech, Inc., come in a variety of sizes and voltages from 18 to 144 kW. Standard CN heater features include overheat protection, an external "push stop" button, a digital control panel displaying setpoint and actual temperature, a door safety switch, a copper and brass heat exchanger, incoloy elements and a NEMA 4 or 12 enclosure. The heaters also feature temperature modulation to +/-1 deg. F.