Bosch BOVA Series - P3 ( Compressor over Current Protection); Hb ( High Pressure(PT) Protection in Heating); P0 (High Module Radiator Temperature (Tf)Protection)

Installation Instructions Bosch IDS BOVA | 29
Bosch Thermotechnology Corp. | 12.2016
Data subject to change
Hb ( High pressure(PT) protection in Heating)
Diagnosis Handling
Check whether the service
valves are open
Yes
Check whether indoor unit is
normal by filter and airflow
Yes
Check whether indoor air inlet
temp. is over 86°F
No
Restart system and check
whether EEV is working
Yes
Make a comparison between
the pressure gauge and the
read from check data
Open the service valve
No
Exclude indoor unit fault
reasons and restart
No
Remove e.g. indoor side
E-heater or other heat
sources
Yes
Reseat or replace the
PT sensor
No
Reseat the EEV throttle
No
Yes
Figure 47
P3 ( Compressor over current protection)
Diagnosis
Handling
Check whether the service
valves are open
Yes
Check whether outdoor unit
motor is abnormal and the
outdoor condenser coil is
blocked
No
No
Check whether compressor
wiring is normal
Yes
Check whether compressor
insulation resistance is greater
than 100KΩ
Yes
Restart system and check whether
the difference of high and low
pressure is more than 30 PSI after
compressor running 10 min
Yes
Check whether the
compressor current is more
than 18A when protection
Open the service valve
No
Replace the fan or
remove all the barriers
Yes
Wiring correctly according to
the wiring diagram
Replace compressor
No
Yes
Replace compressor
No
Replace the board
Replace the compressor
No
Figure 48
Error Code Description
P0 High module radiator temperature (TF) protection
Table 15
P0 (High module radiator temperature (TF)protection)
Diagnosis Handling
Check whether there`s dust or
fallen leaves influencing
radiator
No
Check whether the Tf is
normal according to Table
2(between temperature and
resistance)
Yes
Clean all the dust
and fallen leaves
Yes
Replace Tf sensor
Restart system and check
whether the fan and motor
can normally operate
Replace the fan and motor
No
No
Yes
Operate system and check
whether there`s the same fault
Operate normally
No
Yes
Figure 49
Error Code Description
P2 Low pressure(PT) Protection in cooling
H5 System lockup, 5 times (P2) protection in 100 minutes
P4 High compressor discharge temperature(T5) protection
Table 16
P2 ( Low pressure(PT) Protection in cooling)
H5 ( System lockup, 5 times (P2) protection in 100 minutes)
Diagnosis Handling
Check whether indoor unit is
normal by valve, filter, airflow
and throttle
Yes
Check whether the service
valves are open
Yes
Check whether the charge is
correct by subcooling
according to installation guide
in charge mode when cooling
Yes
Check whether the pressure
transduce is measuring
properly from the 8
th
or 11
th
data of check when cooling
Exclude indoor unit
fault reasons and
restart
No
Open the service valve
No
Adjust the charge
No
Replace the pressure
transducer
No
Yes
Figure 50