A5 Error (Low Water Pressure) - Bosch Singular 4000 Service Manual

8.4 A5 Error (Low Water Pressure)

Error
Low water pressure error
Checkpoint
Table 27
Figure 16
Singular Combi Boiler - BTC 439002301 A (12.2021)
Description
Internal pipe pressure decrease error
Internal pressure in pipes <= 4.3PSI error occurs
—
 Check the input voltage of the pressure sensor
Color: Red – Black (DC 5 V)
—
 Check the output voltage of the pressure sensor
Color: White – Black
—
 Check the internal pressure in pipes
Check the assembly of the
control board and the pressure
sensor and reassemble them.
Internal
pressure in
pipes <=4.3PSI
No
Check the
pressure sensor
input voltage
Yes
Check for any
pipe leakage
No
Replace the control board
Yes
Fill the water
No
Replace the control board
Red-Black: 5 V
Yes
Check the pipes
Service Manual
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