Troubleshooting - Bosch OptiFlow Professional GWH12 1 CTD E23 F3 OL Installation Manual

18 | Troubleshooting

8 Troubleshooting
Fitting, maintenance and repair must only be carried out by authorised technicians. The following table describes the possible
solutions.
Display
A0
A1
A4
A7
A9
C7
CA
CF
C1
E0
E1
Table 9
6 720 810 559 (2016/06)
Description
Cold and hot temperature sensor damaged.
Temperature inside the water heater housing is high
(heat exchanger calcified or sooted).
Faulty air temperature sensor.
Faulty hot water outlet temperature sensor.
Hot water temperature sensor is not fitted properly.
Incoming gas pressure low.
Faulty fan.
Water flow above maximum specified value.
Blocked flue gas outlet.
Air flow sufficient for start-up.
Failure of control module.
Hot water temperature sensor detects overheating.
Solution
▶ Check temperature sensor and associated
connections.
▶ If the problem persists, call an authorised
service technician.
▶ The appliance automatically regulates its
performance to avoid overheating.
▶ If the problem persists, call an authorised
service technician.
▶ Call an authorised service technician.
▶ Check temperature sensor and associated
connections.
▶ If the problem persists, call an authorised
service technician.
▶ Check fitting.
▶ Check incoming pressure.
▶ Check if the fan is properly connected to
ECU.
▶ If the problem persists, call an authorised
service technician.
▶ Check incoming water pressure.
▶ Install a pressure limiting valve if necessary.
▶ Remove dirt or any other impediment in the
flue and air inlet.
▶ Close and open a hot water tap.
▶ If the problem persists, call an authorised
service technician.
▶ Unplug the electrical connection for 10
seconds.
▶ Reconnect and restart the appliance.
▶ If the problem persists, call an authorised
service technician.
▶ Let the appliance cool and try again.
▶ If the problem persists, call an authorised
service technician.
OptiFlow Professional