Problem Solving; Error Code Diagnostics - Bosch Greentherm 9800 SEO 160 Installation And Operating Instructions Manual

38 | Problem solving

11 Problem solving

11.1 Error code diagnostics

To remove error codes from the display,
▶ Press the ON/OFF button more than 3
sec. (long press).
Display Description
A0 Water temperature sensors [17] [19] [20]
disconnected or damaged.
A1 Air temperature inside the cabinet [18] is above
158 °F. Appliance regulates power to protect
against overheat.
A2 External water temperature sensor/aquastat [21]
disconnected, damaged or not properly installed.
A3 Exhaust temperature sensor fault [15].
A4 Air temperature sensor [18] disconnected or
damaged.
A5 Condensing unit flue temperature sensor [16]
disconnected or damaged.
A6 Inlet cold water temperature sensor [20]
disconnected or damaged.
A7 Heat exchanger hot water temperature sensor
[16] disconnected or damaged.
A8 Outlet hot water temperature sensor [17]
disconnected or damaged.
Table 20
6 720 817 281 (2017/05)
Installation, maintenance and repair must only be carried out
by qualified contractors. The following table describes the
solutions for possible problems.
Solution
▶ Check sensor wire connections.
▶ Replace the sensor and/or wire connections, if the
problem persists.
▶ External air temperature is above 140 °F.
▶ Check for flue leakages inside the appliance or in
concentric vent.
▶ Check temperature sensor and associated
1) 2)
connections.
▶ Check sensor position in the tank pocket.
▶ Verify if correct recirculation settings are in use
(section 6.4.1).
▶ Replace the sensor and/or wire connections, if the
problem persists.
▶ Check sensor wire connections.
▶ Replace the sensor and/or wire connections, if the
problem persists.
▶ Check sensor wire connections.
▶ Replace the sensor and/or wire connections, if the
problem persists.
▶ Check sensor wire connections.
▶ Replace the sensor and/or wire connections, if the
problem persists.
▶ Check sensor wire connections.
▶ Replace the sensor and/or wire connections, if the
problem persists.
▶ Check sensor wire connections.
▶ Replace the sensor and/or wire connections, if the
problem persists.
▶ Check connections or replace sensor.
▶ Replace the sensor and/or wire connections, if the
problem persists.
Greentherm 9800 SEO 160/199 | SECO 199
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