Bosch Climate 5000 Series Service Manual page 63

7.6.8 Overload current protection diagnosis and solution (PC 08)
Error Code
Malfunction decision conditions
Supposed causes
Table 37
Troubleshooting:
Is system pressure too high ?
Check whether the refrigerant
Check whether the refrigerant
Figure 82
Bosch Climate 5000 Series Ducted Type (Medium & High Static) Air Conditioner / Heat Pump (11.2022)
PC 08
An abnormal current rise is detected by checking the specifi ed current detection circuit.



Was the protection activated
Was the protection activated
in standby?
in standby?
No
Is the power voltage is normal ? No
Is the power voltage is normal ?
Yes
Is outdoor terminal voltage
Is outdoor terminal voltage
No
normal
normal
Yes
Is the voltage between L and N
Is the voltage between L and N
No
is normal
is normal
Yes
Yes
Is the current normal
Is the current normal
No
Power on and measure the
Power on and measure the
voltage between P and N .
voltage between P and N .
While the unit is i n standby,
While the unit is i n standby, y y
is the voltage between P and N
is the voltage between P and N
is around DC 310 V, 340 V or
is around DC 310 V, 340 V or
380 V? When start up the unit ,
380 V? When start up the unit ,
is it in 220 V~400 V?
is it in 220 V~400 V?
Yes
Is the outdoor ambient
Is the outdoor ambient
temperature is higher than Yes
temperature is higher than
50 ?
50 ?
No
Is the outdoor unit
Is the outdoor unit
Ensure that the outdoor unit ventilate
Ensure that the outdoor unit ventilate
ventilation functioning No
ventilation functioning
properly?
properly?
Yes
Please refer to the solution of the
Please refer to the solution of the
Is the outdoor fan running
Is the outdoor fan running
No " fan speed is operating outside of
" fan speed is operating outside of
properly?
properly?
the normal range " malfunction.
the normal range " malfunction.
Yes
Clean the heat exchanger
Yes
Clean the heat exchanger
Is the heat exchanger dirty ?
Is the heat exchanger dirty ?
No
Replace outdoor main
Replace outdoor main
board. Does a problem still
board. Does a problem still
exist?
exist?
Yes
Recycle the overcharged
Recycle the overcharged
Yes
Is system pressure too high ?
No
system is running normally
system is running normally
Power supply problems
System blockage
Outdoor PCB faulty
Restart the unit when the power supply
Restart the unit when the power supply
returns to normal
returns to normal
Is the power wiring Reconnect the
Is the power wiring Reconnect the
wired correctly? power wiring
wired correctly? power wiring
Are L and N wired
Are L and N wired
Reconnect L and N
Reconnect L and N
properly?
properly?
Replace the outdoor main PCB
Replace the outdoor main PCB
Is the wiring of the
Is the wiring of the
No
reactor properly wired ?
reactor properly wired ?
Yes
Stop the unit
Stop the unit
Are the reactor and
Are the reactor and A
inductance functioning
inductance functioning
normally
normally
is working properly
is working properly
Yes
refrigerant
refrigerant

Wiring mistake

Compressor malfunction
Yes
No Reconnect the wiring
Reconnect the wiring
d
No Replace reactor
Replace reactor
For certain models, outdoor PCB could not be removed
separately. In this case, the outdoor electric control box
should be replaced as a whole.
Service Manual
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