| 摘要 |
PURPOSE:To prevent the space heating effect from remarkably decreasing during a space heating operation by stopping power supply to a relay when the temperature of external air lowers during the space heating operation, and supplying power to a damper motor via a second limit switch to return the damper to a close position. CONSTITUTION:The control unit comprises a single-pole, double-throw type relay switch 43 opened or closed by the variation in a pressure on the low pressure side of a refrigeration cycle of the air conditioner; a single-pole, double-throw type first limit switch 49 switches by the required rotation of a damper motor; and a second limit switch 50 connected in series to the motor 29 and switches by the required rotation of the motor 29. The switches 43 and 49 are connected between a power source 40 and the switch 50. At the time the pressure on the low pressure side of the refrigeration cycle lowers during the freezing cycle, a switch 43 is changed over when the pressure on the low pressure side of the freezing cycle during the space heating operation to rotate the motor at a required rotational speed to close the damper. Thereafter, the switches 49 and 50 are changed over to interrupt the power supply to the motor 29, and when the switch 43 returns to the original position, the motor 29 is driven via the switch 49.
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