General Functions SiBE04-10138 Main Function1.174-Way Valve Function CompensationOutline When the initial start of compressors is required after power is on or at operation mode’s alteration(Cooling/Dry ↔ Heating) that the a switch-over of a 4-way valve takes place, it secures the necessarydifferential pressure by restricting the operation frequency in the lower limit in a certain period, and theswitch-over action is ensured.Caution To avoid the temperature rise of the 4-way valve coil, the 4-way valve coil is energized in heatingoperation.Details of theControl1. If a 4-way valve is OFF when compressors stop, it will be ON at this time.2. If a 4-way valve was ON when compressors operated in the last time, it will be ON at this time.3. At the start of compressors.4. At the initial start of compressors after power is reset.In case 1. and 3. are under the simultaneous condition of AND (it indicates Heating) or 2. and 3 are underthe simultaneous satisfaction of AND (it indicates Cooling), or condition 4. is adapted, the processingapplies A seconds after compressors begin operating and to set B Hz for the lower limit of operationfrequency.A (sec) B (Hz)Cooling 50~71 Class 60 56Heating50 Class 60 5660 Class 60 4271 Class 60 32SiBE04-101.book Page 38 Monday, October 15, 2001 3:08 PM
