Bosch BOVB36-18 - Page 33

Installation Instructions Bosch IDS BOVB 18 | 33
Bosch Thermotechnology Corp. | 10.2020
Data subject to change
Figure 52
P4 (High compressor discharge temperature (T5) protection)
Diagnosis Handling
Yes
Check whether outdoor and
indoor unit motor is abnormal
or whether coils (outdoor and
indoor) are blocked
No
Check whether the charge is
correct by subcooling
according to installation guide
in charge mode when cooling
Yes
Check whether the EEV/TXV is
normal for throttle
(wire seated coil)
Replace the fan or
remove all the barriers
Yes
Adjust the charge
No
Re-power and check
again, if the same, replace
the EEV.
No
Yes
Check whether the T5 is normal
according to Table 28 (between
temperature and resistance)
Replace the T5 sensor
No
Check whether the compres-
sor is normal (abnormal noise,
abnormal vibration)
Replace the compressor
No
Yes
Check whether the service
valves are open
Yes
Open the service valve
No
Error Code Description
E4 Temperature sensor fault (T3, T4, T5)
H8 Pressure transducer (PT) fault
F1 High pressure switch (HPS) fault
Table 18
Figure 53
E4 (Temperature sensor fault (T3, T4, T5)
Diagnosis Handling
Check whether sensor
T3/T4/T5 are seated
(T4 for Heat Pump only)
Yes
Unplug the sensor, check
whether the resistance of
T3/T4 is in the range of
Ta b l e 24
Yes
Unplug the sensor, Check
whether the resistance of T5
is in the range of Table 28
Yes
Check whether the display the
shows the same error code
when re-powered on
Reseat the sensor
according to wiring diagram
No
Replace the fault T3/T4
sensor
No
Replace the fault T5 sensor
No
No
Yes
and normal
Keep running
Figure 54
H8 (Pressure transducer (PT) fault)
Diagnosis
Handling
Yes
Yes
Check whether there is the
same fault
No
No
Keep running
No
Check whether pressure
transducer (PT) wiring are
seated and normal
Wire according to the
diagram correctly
Is the pressure transducer
working properly? Compare
the data between pressure
measurement and No 9
(cooling) or No 10 (heating)
check point value (by pressing
check button)
Replace the pressure
transducer
Yes