Installation Instructions
15.11 Error Code Troubleshooting
Error Code
Description (Sensor)
P1
High pressure switch (HPS) protection
P5
Condenser coil temperature (T3) protection in cooling
P3
Compressor over current protection
Table 15
P1 (High pressure switch (HPS) protection)
Diagnosis
Check whether the service
valves are open
Yes
Check whether the switch
wires are seated normally
Yes
Check whether high pressure
switch is closed
Yes
Check whether indoor and
outdoor units are normal by
filter and airflow
Yes
Cooling mode refers to P5
Figure 47
Bosch Thermotechnology Corp. | 10.2020
Handling
No
Open the service valve
No
Reseat the wires according
to wiring diagram
No
Replace high pressure switch
No
Exclude all fault reasons
and restart
P5 (Condenser coil temperature (T3) protection in cooling)
Diagnosis
Check whether the service
valves are open
Yes
Check whether T3 is normal
according to Table 27 (between
temperature and resistance)
Yes
Check whether outdoor unit
motor is abnormal or whether
the outdoor condenser coil is
blocked
No
Check whether there is short
circuit in air outlet and inlet side
No
Check whether the charge is
correct by subcooling
according to installation guide
in charge mode when cooling
Yes
Check whether there is
normal throttle
Yes
Figure 48
Bosch IDS BOVB 18 | 31
Handling
No
Open the service valve
No
Replace the T3 sensor
Replace the fan or
Yes
remove all the barriers
Yes
Correct air return
short circuit.
No
Adjust refrigerant charge
No
Adjust or replace the EEV
throttle
Data subject to change