General Functions SiBE04-10136 Main Function1.15 Freeze up Prevention Function in CoolingOutline During Cooling/Dry operation, when the heat exchanger’s temperature falls down excessively, the capacitysupply will be reduced (frequency step down) so as to prevent freeze of the heat exchanger and thecreation of dew on a rotor caused by a excessive capacity supply to the indoor unit.Details of theControl This air conditioner is equipped with a guard timer to retard the anti-freezing control for 6 to 10 min.even when the heat exchange temperature has been lowered, in consideration of unstable conditionwhich may be seen after the operation is started or the thermostat starts to work. When 6 to 10 min. elapses, anti-freezing control is conducted for each zone in accordance with the heatexchange temperature.∗ DTO : Freeze protection temperature of heat exchanger The restriction for frequency is not conducted in the return area by means of freeze protection control. Frequency is increased approximately every 2 Hz/min. in the up-area. Frequency alteration in the steady area is not conducted. Frequency - down is carried out in the step down area approximately every 2 ~ 4 Hz/min.. Compressors stop in the stop area. After compressor stops, fan keeps operating in 700 rpm for H typeand 800 rpm for J type (LL operation), aiming at rising heat exchanger’s temperature.Setting a constant 50 Class 60 Class 70 ClassDTO4 13˚CDTO3 6˚CDTO2 5˚CDTO1 3˚CDTO0 0˚CReturnat the descent ofheat exchanger temp.at the ascent of heat exchanger temp. Return from stop.DTO0DTO1DTO2DTO3DTO4Step down areaSteady areaStop areaUp-area(R1228)SiBE04-101.book Page 36 Monday, October 15, 2001 3:08 PM
