Bosch 19 SEER Series Operation Manual page 30

3 0 | Bosch Inverter Ducted Packaged Heat Pump
Error Code Description
E4 Temperature sensor fault (T3, T4, T5,Th, T3L, TF)
H8 Pressure transducer (PT) fault
F1 High pressure switch (HPS) fault
Table 21
E4 (Temperature sensor fault (T3, T4, T5, Th, T3L, TF)
Diagnosis
Check whether sensor
T3/T4/T5/Th/T3L/TF are
seated and normal
(T4 for Heat Pump only)
Yes
Unplug the sensor, check
whether the resistance of
T3/T4/Th/T3L is in the range
of Table 27
Yes
Unplug the sensor, Check
whether the resistance of T5/Tf
is in the range of Table 28
Yes
Check whether the display the
shows the same error code
when re-powered on
Yes
Figure 37
H8 (Pressure transducer (PT) fault)
Diagnosis
Check whether pressure
transducer (PT) wiring are
seated and normal
Yes
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)
Yes
Check whether there is the
same fault
Yes
Figure 38
Data subject to change
Handling
No
Reseat the sensor
according to wiring diagram
No
Replace the fault T3/T4
Th/T3L sensor
No
Replace the fault T5/Tf sensor
No
Keep running
Handling
No Wire according to the
diagram correctly
No
Replace the pressure
transducer
No
Keep running
F1 (High pressure switch (HPS) fault)
Diagnosis
Check whether high pressure
switch (HPS) wiring is seated
and normal
Yes
Check whether the
resistance of HPS is close to
0KΩ
Yes
Check whether there is the
same fault
Yes
Figure 39
Installation & Operation Manual
Handling
No
Wiring according to the
diagram correctly
No
Replace high pressure
switch
No
Keep running
03.2019 | BTC 761701105 A