Mitsubishi Electric MUZ-FS06NA Service Manual page 29

NOTE: Blinking patterns of this mode differ from the ones of TROUBLESHOOTING CHECK TABLE (10-3.).
The left
lamp of the
OPERATION Abnormal point
INDICATOR (Failure mode/protection)
lamp
(Indoor unit)
10-time blink Discharge temperature
2.5 seconds
OFF
Bus-bar voltage (DC)
11-time blink
2.5 seconds
OFF
Each phase current of
compressor
14-time blink Stop valve (Closed valve)
2.5 seconds
OFF *1
4-way valve/
Pipe temperature
16-time blink Outdoor refrigerant system
2.5 seconds
abnormality
OFF *1
*1 There is possibility that diesel explosion may occur due to the air mixied in the refrigerant circuit.
First, ensure that there are no leakage points on the valves, flare connections, etc. that allow the air to flow into the refrigerant circuit, or no blockage points (e.g.
clogged or closed valves) in the refrigerant circuit that cause an increase in pressure.
If there is no abnormal point like above and the system operates cooling and heating modes normally, the indoor thermistor might have a problem, resulting in
false detection.
Check both the indoor coil thermistor and the room temperature thermistor, and replace faulty thermistor(s), if any.
(Do not start the operation again without repair to prevent hazards.)
OBH873
LED indication
(Outdoor P.C. board)
Temperature of discharge temperature
thermistor has been 122°F (50°C) or
less for 20 minutes.
—
8-time blink Bus-bar voltage of inverter cannot be
2.5 seconds OFF detected normally.
9-time blink Each phase current of compressor
2.5 seconds OFF cannot be detected normally.
14-time blink • Closed valve is detected by
2.5 seconds OFF
compressor current.
• An abnormality of the indoor
thermistors, the defrost thermistor or
ambient temperature thermistor is
detected.
16-time blink • The 4-way valve does not work
2.5 seconds OFF
properly.
• The indoor coil thermistor detects an
abnormal temperature.
• An abnormality of the indoor
thermistor is detected.
1-time blink • A closed valve and air trapped in the
refrigerant circuit are detected based
2.5 seconds OFF
on the temperature sensed by the
indoor and outdoor thermistors and
the current of the compressor.
• An abnormality of the indoor
thermistors, the defrost thermistor or
ambient temperature thermistor is
detected.
29
Condition Remedy
• Refer to 10-5. "Check
of LEV".
• Check refrigerant
circuit and refrigerant
amount.
• Refer to 10-5. "How
to check inverter/
compressor".
• Check stop valve.
• Refer to "TEST
POINT DIAGRAM
AND VOLTAGE" on
the service manual of
indoor and outdoor unit
for the characteristics
of the thermistors. (Do
not start the operation
again without repair to
prevent hazards.)
• Check the 4-way
valve.
• Replace the inverter
P.C. board.
• Refer to "TEST
POINT DIAGRAM
AND VOLTAGE" on
the service manual of
indoor and outdoor unit
for the characteristics
of the thermistors. (Do
not start the operation
again without repair to
prevent hazards.)
• Check for a gas leak
in a connecting piping
etc.
• Check the stop valve.
• Refer to 10-5.
"Check of outdoor
refrigerant circuit".
• Refer to "TEST
POINT DIAGRAM
AND VOLTAGE" on
the service manual of
indoor and outdoor unit
for the characteristics
of the thermistors. (Do
not start the operation
again without repair to
prevent hazards.)
Indoor/outdoor
Outdoor unit
unit failure
failure mode
mode recall
recall function
function
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