Bosch BMS500-AAU036-1AHCXC - Current Overload & Speed Issues (PC 08, 44, 46, 49)

| 71
Service Manual
Bosch Climate 5000 Series Ductless Air Conditioner / Heat Pump Multi Zone Outdoor Units (01.2023)
8.6.10 Current overload protection (PC 08) Outdoor unit zero speed
protection (PC 44) Compressor speed has been out of control (PC
46)Compressor overcurrent failure (PC 49)
Error Code PC 08/PC 44/PC 46/PC 49
Malfunction decision conditions If the outdoor current exceeds the current limit value, the LED will display the failure.
Supposed causes
f Improper / Incorrect Wiring
f Over load protector faulty
f System blockage
f Outdoor PCB faulty
Table 41
Troubleshooting:
Figure 75
C
u
r
r
e
n
t
p
r
o
t
e
c
t
i
o
n
o
f
c
o
m
p
r
e
s
s
o
r
Currentprotectionofcompressor
- 18K Regular model: 15A
- 27K Regular & 18K Max Performance models: 18.5A
- 36K Regular & 27K Max Performance models: 22.5A
- 48K Regular & 36K Max Performance models: 28A
Yes
R
e
p
l
a
c
e
t
h
e
e
l
e
c
t
r
i
c
c
o
n
t
r
o
l
b
o
x
Replacethe electric controlbox
C
h
e
c
k
w
h
e
t
h
e
r
t
h
e
r
e
f
r
i
g
e
r
a
n
t
s
y
s
t
e
m
i
s
o
k
Checkwhether the
refrigerant system
is ok
h
e
c
k
w
h
e
t
h
e
r
t
h
e
o
u
t
d
o
o
r
a
mb
i
e
n
t
t
e
m
p
e
r
a
t
u
r
e
i
s
h
i
g
h
e
r
t
h
a
n5
0
ć
Checkwhether the
outdoorambient temperature
is higher than 50ć
No
Stop the systemYes
C
h
e
c
k
w
h
e
t
h
e
r
t
h
e
Checkwhether the
outdoor unit has
proper venlaon and clearance.
No
Make sure the outdoor unit has
proper venlaon and clearance
Yes
Check if the refrigerant
pipe is blocked
No
Yes
C
h
e
c
k
w
h
e
t
h
e
r
t
h
e
h
e
a
t
e
x
c
h
a
n
g
e
r
i
s
d
i
r
t
y
Checkwhether the
heat exchangerisdirty
No
C
l
e
a
n
t
h
e
h
e
a
t
e
x
c
h
a
n
g
e
r
Cleanthe heat exchangerYes
Yes
a
n
d
c
h
e
c
k
w
h
e
t
h
e
r
t
h
e
s
y
s
t
e
m
c
a
n
r
u
n
n
o
r
m
a
l
l
y
Replace outdoor PCB
andcheck whetherthe
systemcan run normally
No
Yes
Problemissolved
R
e
p
l
a
c
e
o
u
t
d
o
o
r
m
a
i
n
b
o
a
r
d
Replaceoutdoor main boardNo
Check whether the input current
of power supply wire is more than
Let the refrigerant out, then use the high
pressure nitrogen or refrigerant to blow pipe,
vacuumize and charge the refrigerant again