Troubleshooting Guide

7.8 F0/PC 08 (Current overload protection diagnosis and solution)
Description: An abnormal current rise is detected by checking the specified current detection circuit.
Recommended parts to prepare:
• Connection wires
• Reactor
• Outdoor fan
• Outdoor PCB
Troubleshooting and repair :
Was the protection activated
in standby ?
Yes
Is the current normal?
Yes
No
Replace the outdoor main PCB
Is the input voltage normal?
Is outdoor terminal voltage
normal?
Restart the unit when the power
supply returns to normal
No
Yes
No
Reconnect the
power wiring
Yes
Is the voltage between L and N
is normal?
Yes
No
Is the power wiring
wired correctly?
Reconnect L and N
Are L and N wired
properly ?
No
No
Is the wiring of the
reactor properly wired?
Reconnect the wiring No
Are the reactor and
inductance functioning
normally
Yes
Replace reactor
No
Is the outdoor ambient
temperature is higher than
122°F?
No
Stop the unit until temps drop
Yes
Is the outdoor unit
able to ventilate
properly?
Yes
Ensure that the outdoor unit is able
to ventilate properly
Is the heat exchanger dirty?
No
Clean the heat exchanger
Yes
Check whether the refrigerant
system is running normally
Replace outdoor main
board. Does a problem still
exist?
Yes
No
Is the outdoor fan running
properly?
Please refer to the solution of the
"fan speed is operating outside of
the normal range" malfunction.
No
Yes
No
Yes
Yes
Is system pressure too high?
Recycle the overcharged
refrigerant
Yes
Power on and measure the
voltage between P and N.
 Troubleshooting 29
Note: For certain models, outdoor PCB cannot be removed separately. In this case, the outdoor electric
control box should be replaced as a whole.
While the unit is in standby,
is the voltage between P and N
around DC 310V, 340V or 380V?
When starting up the unit, is it
in range of 220V~400V?
Skip this step for
models which electric
control box cover
cannot be removed. See
the disassembly guide
for details.