Bosch BRBA-36HWD1N1-M18 - Page 31

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Installation Instructions
Bosch 18 SEER2 Series Inverter Ducted Packaged Heat Pump - BTC 761703103 A (11.2022)
Error Code Description
E4 Temperature sensor fault (T3, T4, T5,Th, T3L)
H8 Pressure transducer (PT) fault
F1 High pressure switch (HPS) fault
Table 25
Figure 40
E4 (Temperature sensor fault (T3, T4, T5, Th, T3L)
Diagnosis Handling
Check whether sensor
T3/T4/T5/Th/T3L are
(T4 for Heat Pump only)
Yes
Unplug the sensor, check
whether the resistance of
T3/T4/Th/T3L is in the range
of Table 34
Yes
Unplug the sensor, Check
whether the resistance of T5/Tf
is in the range of Table 35
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
Th/T3L sensor
No
Replace the fault T5/Tf sensor
No
No
Yes
seated and normal
Keep running
Figure 41
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
Figure 42
F1 (High pressure switch (HPS) fault)
Diagnosis
Handling
Yes
Check whether the
resistance of HPS is close to
0KΩ
No
Replace high pressure
switch
No
Check whether high pressure
switch (HPS) wiring is seated
and normal
Reseat wiring according
to thewiring diagram
Yes
Yes
Check whether there is the
same fault
Keep running
No