Siemens LMV5 Series Basic Documentation

Also see for LMV 5 Series: User manual Manual Technical instructions Quick start guide Manual

58/278Siemens Building Technologies Basic Documentation LMV51... CC1P7550enHVAC Products 5 Fuel / air ratio control (FARC) 01.10.2003In Phase 36, all actuators are driven to their ignition positions. For that purpose - like inprepurging - a maximum time is available within which the ignition position must bereached → position check.Ignition takes place only when the required position is reached. The ignition positioncan be adjusted for all actuators, depending on the type of fuel.Parameters: LMV51... LMV52...IgnitionPosAir x xIgnitionPosGas x xIgnitionPosOil x xIgnitionPosAux x xAux2 xAux3 xVSD xWhen ignition has taken place and the flame has stabilized, the actuators must bebrought into line. For that purpose, the control unit drives the actuators to their basicpart load position (low-fire) as defined by the curves.The actuators which, for ignition, have assumed a special position, travel at individuallycalculated speeds to ensure that all of them will reach the part load position at thesame time.FuelAirAux25 % 50 % 75 % 100 %7550d03E/02020°90°Low fire Ignition positionsPositionLoadTraveling to the low-fire position after ignitionNote: The system also permits ignition positions that lie outside the range defined byfuel / air ratio control, that is, not between high-fire and low-fire.In the operating position, the dampers are adjusted according to demand. The ratiocurves are defined for gas and oil.For modulating operation, the output can be adjusted in increments of 0.1°.The actuators travel to the defined ratio curves.In multistage operation, 2 or 3 load points can be approached.For more detailed information, refer to section «Operating position».After there is no more demand from the controller, the fuel / air ratio control system firstchanges to low-fire (Phase 62) before the fuel valve close. For that purpose, amaximum time is available which can be parameterized → part load shutdown.IgnitionTraveling to theoperating positionOperationEnd of operatingposition