... 230V(AC110V/AC24V) 220V LCD Display FCU thermostat E51.42 1. 2-pipe FCU thermostat2. Auto, low, mid ... speed fan and an on/off valve actuator in 2-pipe/4-pipe FCU system, to ... fans and valves, E51.42 is designed to control the valve in heating or cooling systems to ... maintain the desired setpoint temperature in Commercial buildings, Residential buildings, Light industrial buildings... ...