Bosch BOVB 18 Series Installation Instructions Manual page 32

3 2 | Bosch IDS BOVB 18
P3 (Compressor over current protection)
Diagnosis
Check whether the service
valves are open
Yes
Check whether outdoor unit
motor is abnormal and the
outdoor condenser coil is
blocked
No
Check whether compressor
wiring is normal
Yes
Check whether compressor
insulation resistance is greater
than 100KΩ
Yes
Restart system, put in force mode,
and check whether the difference
of high and low pressure is more
than 30 PSI after compressor has
run for 10 mins
Yes
Check whether the
compressor current is more
than 15A for 2/3 ton and 20A
for 4/5 ton when protected
Yes
Figure 49
Error Code Description
P0 High module radiator temperature (TF) protection
Table 16
P0 (High module radiator temperature (TF) protection)
Diagnosis
Check for dust or debris
blocking the control board
heat sink
No
Check if all screws are
properly installed and if
thermal paste is properly
applied
Yes
Restart system and check
whether the fan and motor
can operate normally
Yes
Operate system and check
whether there`s the same fault
Yes
Figure 50
Data subject to change
Handling
No
Open the service valve
Yes Replace the fan or
remove all the barriers
No
Wire correctly according to
the wiring diagram
No
Replace the compressor
No
Replac e the compressor
No
Replace the board
Replace the compressor
Handling
Clean all the dust
Yes
and debris
No Follow board replacement
instruction for correct steps
No
Replace the fan and motor
No
Operate normally
Error Code Description
P2 Low pressure (PT) Protection in cooling and heating
H5 System lockup, 5 times (P2) protection in 100 minutes
P4 High compressor discharge temperature(T5) protection
Table 17
P2 (Low pressure (PT) Protection in cooling)
H5 (System lockup, 5 times (P2) protection in 100 minutes)
Diagnosis
Check whether the service
valves are open
Yes
Do superheat and subcooling
meet required values? (Refer
to section 14 system charge
adjustment)
Yes
Are the TXV, blower fan motor
working properly? Is there any
blockage on filter? Are the EEV
and outdoor fan motor working
properly?
Yes
Is the pressure transducer
working properly? Compare
the data between pressure
measurement and
No 9 (cooling) or
No 10 (heating) values
(by press check button).
Yes
Figure 51
Installation Instructions
Handling
No
Open the service valve
No
Adjust charge
No
Fix all these and restart
the system
No Replace the pressure
transducer
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