Hitachi RAS-10JH4 Service Manual page 78

THE SUPPORT FUNCTION OF FAILURE DIAGNOSIS
No.
Function Name
1 Self-diagnosis indication
function
<Indication on the indoor unit
side>
<Indication on the outdoor
unit side>
2
Self-diagnosis memory
Self-diagnosis of
3
communication circuit
• The "timer lamp" indicates the failure mode detected on the indoor unit side by
its blinking frequency while the "filter lamp" indicates the failure mode detected
on the outdoor unit side by its frequency.
• A failure detected on the outdoor unit side will be indicated by the blinking
"filter lamp" after retry operation has been performed several times.
For some failure modes, only the retry operation is repeated without lamp
indication.
<Failure modes with repeated retry operation and without indoor unit lamp
indication are as follows:->
OH thermistor temperature rise
Outdoor unit communication error
Abnormal supply voltage
Failure with low occurrence frequency
• The "LD301" indicates the failure mode detected on the outdoor unit side by its
blinking frequency. Upon failure detection, the outdoor unit will shut down and
the LD301 continues to blink until the unit is restarted. (In the event of
communication errors, the LD301 continues to blink until communication is
restored.)
• Failure modes detected on indoor and outdoor unit sides are stored in the non-
volatile memory of the indoor unit. These modes can be read later.
(This memory is retained even if the power is turned off.)
• Data of the failure modes detected on the outdoor unit side is written in the
memory every time a failure occurs, so the failure mode can be checked on the
indoor unit side without retry operation. In addition, minor failure modes which
are not indicated by usual self-diagnosis indication function are also stored in
the memory and indicated. (These minor failure modes may not be stored in
the memory in case of outdoor communication error.)
• The past 5 failure modes are stored in the memory.
• There is a function to erase the memory. Using the memory clear function,
failure symptom with low occurrence frequency can also be detected by
reading and checking the failure modes in the memory every few days.
• This is a function to perform self-diagnosis of communication circuit to identify
the failure part on the communication circuit of the indoor and outdoor unit
sides.
• This function is used for detailed diagnosis in the event that any abnormality on
communication circuit is suspected.
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Description