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22
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(6)
Serial signal transmission error protection
(a)
Purpose:
Prevents malfunction resulting from error on the indoor
↔
outdoor signals.
(b) Detail of operation:
When the indoor unit controller
↔
outdoor unit controller signals cannot be received, the compressor
is stopped immediately. Simultaneously, the red LED on the printed circuit board of outdoor unit
controller flashing 6 times for 0.5 second at intervals of 8 seconds. Once the operation stops, it does
not start any more.
(TIMER light on the indoor unit flashing at the same time.)
(7)
Sensor disconnection (room temperature, indoor heat exchanger, outdoor heat exchanger, outdoor air tem-
perature, discharge pipe)
(a)
Room temperature sensor
If the temperature detected by the room temperature sensor is –20ºC or lower continuously for 15 seconds or longer while
operation is stopped, an error indication is displayed.
(b)
Indoor heat exchanger sensor
If the temperature detected by the indoor heat exchanger sensor is –20ºC or lower continuously for 15 seconds or longer
while operation is stopped, an error indication is displayed.
Also, if the temperature detected by the indoor heat exchanger sensor is –20ºC or lower continuously for 3 minutes after
heating operation has started, the indoor unit’s fan speed is forcibly raised to speed 5. After this, the air conditioner is stopped
if the detected temperature remains at –20ºC continuously for 40 minutes.
(c)
Outdoor heat exchanger sensor
If the temperature detected by the outdoor heat exchanger sensor is –50ºC or lower continuously for 15 seconds or longer
while operation is stopped, an error indication is displayed.
Also, the air conditioner is stopped if the temperature detected by the outdoor heat exchanger sensor remains at –50ºC or
lower continuously for 40 minutes after heating operation has started.
(d)
Outdoor air temperature sensor
If the temperature detected by the outdoor air temperature sensor is –40ºC or lower continuously for 15 seconds or longer
while operation is stopped, an error indication is displayed.
(e)
Discharge pipe sensor
After the compressor has operated for 9 minutes continuously, if there is a disconnected signal for the discharge pipe sensor
detected temperature for 15 seconds (less than 7ºC), the compressor stops. After a 3-minute delay, it restarts, but if an
abnormality is detected 4 times continuously, the air conditioner is stopped fully and an error indication is displayed.
