Hitachi RAK-18REF Service Manual

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13. Infrared human presence sensor circuit
With the infrared sensor,the air conditioner can detect the activity level in a room and adjust the
temperature and humidity automatically,thus achieving the purpose of energy saving.
When the activity level in a room is detected,the infrared sensor will be in operation.
And a low-voltage output from the infrared sensor P.W.B. will be magnified by the amplifier comparator
and be transformed the digital signal to microcomputer(IC601).
(The infrared sensor output is [Hi] when the activity level is not detected. On the contrary,output is [Lo].)
If the connector(CN21) is not inserted, it will be considered as no infrared sensor, and no self-diagnosis
indication.
Fig.13
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Sensor P.W.B
Indoor main P.W,B
Microcomputer
Infrared sensor
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(QEF/REF Unse)
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Hitachi RAK-18REF Specifications

General

Brand	Hitachi
Model	RAK-18REF
Category	Air Conditioner
Language	English