| 摘要 |
PURPOSE:To detect the operational status of an outdoor unit by an indoor unit by a method wherein the conductive line on an indoor unit side circuit is insertedly provided with a photo coupler while the conductive line on an outdoor side circuit is also insertedly provided with a thyristor etc. CONSTITUTION:When an outdoor side heat exchanger 13 is frosted in case of heating operation, an outdoor controller 31 turns a switch SW2 OFF stopping a four way valve 12 to start defrosting operation. At this time, the outdoor controller 31 turns a thyristor SCR2 OFF by a thyristor firing circuit 35 at the receiving timing of a cooling transfer command to disconnect a conductive line A turning a photo coupler PHC2 on a circuit 18 OFF. Consequently, an indoor controller 25 may perceive the disconnection of the conductive line A despite turning a thyristor SCR1 ON for commanding heating operation to recognize the defrosting operational status of the outdoor unit. |
