Service Manual

SiUS091133 Check
Service Diagnosis 146
5.8 “Inverter Checker” Check
Check No.15  Characteristics
If an abnormal stop occurs due to compressor startup failure or overcurrent output when using an
inverter unit, it is difficult to judge whether the stop is caused by the compressor failure or some
other failure (control PCB, power module, etc.). The inverter checker makes it possible to judge the
cause of trouble easily and securely. (Connect this checker as a quasi-compressor instead of
compressor and check the output of the inverter)
 Operation Method
Step 1
Be sure to turn the power off.
Step 2
Install the inverter checker instead of a compressor.
Note:
Make sure the charged voltage of the built-in smoothing electrolytic capacitor drops to 10 VDC
or below before carrying out the service work.
Reference:
If the terminals of the compressor are not FASTON terminals (difficult to remove the wire on the
terminals), it is possible to connect wires available on site to the outdoor unit from output side of
PCB. (Do not connect them to the compressor at the same time, otherwise it may result in
incorrect detection.)
Step 3
Activate the power transistor test operation from the outdoor unit.
1) Press the forced cooling operation [ON/OFF] button for 5 seconds.
(Refer to page 384 for the position.)
 Power transistor test operation starts.
(R14926)
(1) Remove the terminals from
the compressor.
(2) Connect the terminals to the
terminals of the inverter
checker.
Compressor
Inverter checker
Be careful not to let the terminals (U,V,W)
touch each other. Otherwise, high voltage
is applied.