Siemens Desigo RXB Technical Manual

43/52Siemens RXB application library (KNX) FNC – Fancoil-Applikationen aus FC-10, FC-11, FC-12 CM110672en_03Building Technologies FNC18 – Two-pipe fan coil (changeover) and radiator 30.11.2007FNC18Two-pipe fan coil (changeover) and radiatorK NX R• Heating/cooling coil: heating only (with LTHW), cooling only (with CHW) orchangeover.• Changeover signal via KNX bus.• Outside air temperature sensor via KNX bus.• Heating with LTHW radiator.• Downdraft compensation• Modulating control of heating/cooling valve and radiator valve.• Automatic or manual fan control.Plant diagramN1 Room controller.R1 Room unit with temp.sensor.B1 Return air sensor.B2 Outside temp. via KNX bus.D1 Window switch.D2 Presence detector.D3 Changeover signal via KNXbus.Q1 Fan (1… 3-speed).YH Heating valve (radiator).YHC Heating/cooling valve (fancoil).10385S21B1YHCQ1N1R1 D1 D2TYHTD3B2TTK N X ROperating diagrams1000TR [°C]Y [%]SpH SpCYHH C1000TR [°C]Y [%]SpH SpCChange-over (Fan-Coil)YHCH C10385D50YHCHeating sequence:The heating coil in the fan coil system operatesin sequence with the radiator, i.e. theheating/cooling valve is only operated after theradiator valve is fully open (thermal valves areoperated in alternation, because fully openhere means 1 second ON / 1 second OFF).Cooling sequence:Control of heating/cooling valve.Y Output signal.TR Room temperature.SpH Effective heating setpoint.SpC Effective cooling setpoint.H Heating sequence.C Cooling sequence.YH Heating valve (radiator).YHC Heating/cooling valve (fancoil).Q14 Fan speed 1.Q24 Fan speed 2.Q34 Fan speed 3.10385D51Change-overTR [°C]YH CQ14Q24Q34SpH SpC