Service Manual

SiUS121502E General Problem Symptoms and Check Items
Service Diagnosis 99
1. General Problem Symptoms and Check Items
Problem Symptom Check Item Details
Reference
Page
None of the units operates. Check the power supply. Check if the rated voltage is supplied. —
Check the types of the indoor units. Check if the indoor unit type is compatible with
the outdoor unit.
—
Check the outdoor temperature. Heating operation cannot be used when the
outdoor temperature is 15.5°CWB (59.9°FWB)
or higher, and cooling operation cannot be used
when the outdoor temperature is below
–10°CDB (14°FDB).
—
Diagnose with remote controller
indication
— 114, 115
Check the remote controller
addresses.
Check if address settings for the remote
controller and indoor unit are correct.
189
Operation sometimes
stops.
Check the power supply. A power failure of 2 to 10 cycles can stop air
conditioner operation. (Operation lamp OFF)
—
Check the outdoor temperature. Heating operation cannot be used when the
outdoor temperature is 15.5°CWB (59.9°FWB)
or higher, and cooling operation cannot be used
when the outdoor temperature is below
–10°CDB (14°FDB).
—
Diagnose with remote controller
indication.
— 114, 115
Some indoor units do not
operate.
Check the type of the indoor units. Check if the indoor unit type is compatible with
the outdoor unit.
—
Diagnose with remote controller
indication
— 114, 115
Units operate but do not
cool, or do not heat.
Check for wiring and piping errors in
the connection between the indoor
and outdoor units.
Check the piping.
Conduct the wiring error check described on the
product diagnosis nameplate.
—
Check for thermistor detection errors. Check if the thermistor is mounted securely. —
Check for faulty operation of the
electronic expansion valve.
Set all the units to cooling operation, and
compare the temperatures of the liquid pipes to
see if the each electronic expansion valve
works.
—
Diagnose with remote controller
indication.
— 114, 115
Diagnose by service port pressure
and operating current.
Check for refrigerant shortage.
136
Large operating noise and
vibrations
Check the output voltage of the
power module.
— 176
Check the power module. — —
Check the installation condition. Check if the required spaces for installation
(specified in the installation manual) are
provided.
—