215 Commissioning5.1.6 Pre-ventilation periodSelect parameter no. 785If an output channel is set to flue gas re-circulation, attention must still be given to P 427.5.1.7 Recirculation DelaySelect parameter no. 427No FMS ETA Short Text Description Min Max Default785 1 1 ZEIT VO Pre-ventilating time in seconds 0 999 30Set the duration of pre-ventilation in this parameter. The commissioning engineer sets this value.P784 sets the lower limit of the pre-ventilation.No FMS ETA Short Text Description Min Max Default427 1 1 VO Del R Number of points of air channel of recirc. (VMS)/delaytime (FMS)0 999 750/10Number of points of an air channel for recirculation(VMS) / delay time (FMS) in seconds.With VMS it is necessary to couple the recirculation flapdelay with an air channel during pre-ventilation. There-fore an air channel is assigned to the recirculation flap(see P 428). The opening of this air channel now deter-mines the moment, when the recirculation flap shallopen. Set in this parameter the number of digits the airchannel has to reach, before recirculation becomesactive.If the device is an ETAMATIC or a FMS, set the delaytime in seconds before the recirculation flap opens,i. e. during this period only the boiler is ventilated.The total pre-ventilation duration (P 785) has to begreater than the value in this parameter.- VMS opening of the air channel for delay of the recirculation channel (in digit)- FMS delay time (in seconds)0 = recirculation channel remains closed during pre-ventilation1... = Delay/delay time of the recirculation channel
