Along with one master contactor that controls on/off switching of system and helps increase MTTF, CF series features optional flow switch that requires water demand before unit starts. Individual fusing for all elements protects against breaker tripping due to water supply failure and subsequent element short. Supplied in NEMA 4 enclosures, series includes CF 120 kW and CF 144 kW units offered in 480 V delta configurations rated for 500,000 BTUs of heating capacity per hour.