Bosch Greentherm T9800 SEO160, Installation And Operating Instructions Manual

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Problem solving
Greentherm T9800 SEO 160/199 | SECO 199 – 6 720 817 281 (2018/12) 44
9 Problem solving
9.1 Error code diagnostics
To remove error codes from the display,
▶ Press the ON/OFF button more than 3 sec. (long press).
Installation, maintenance and repair must only be carried out
by qualified contractors. The following table describes the
solutions for possible problems.
Display Description Solution
A0 Water temperature sensors [17] [19] [20]
disconnected or damaged. ▶ Check sensor wire connections.
1) 2)
▶ Replace the sensor and/or wire connections, if the
problem persists.
1)
A1 Air temperature inside the cabinet [18] is above
158 °F (70 °C). Appliance regulates power to
protect against overheat. ▶ External air temperature is above 140 °F (60 °C).
▶ Check for flue leakages inside the appliance
1)
A2 External water temperature sensor/aquastat [21]
disconnected, damaged or not properly installed. ▶ Check temperature sensor and associated
connections.
1) 2)
▶ Check sensor position in the tank pocket.
▶ Verify if correct recirculation settings are in use
(

section 4.11.1).
▶ Replace the sensor and/or wire connections, if the
problem persists.
1)
A3 Flue gases temperature sensor [15] disconnected
or damaged. ▶ Check sensor wire connections.
1) 2)
▶ Replace the sensor and/or wire connections, if the
problem persists.
1)
A4 Air temperature sensor [18] disconnected or
damaged. ▶ Check sensor wire connections.
1) 2)
▶ Replace the sensor and/or wire connections, if the
problem persists.
1)
A5 Condensing unit flue temperature sensor [16]
disconnected or damaged. ▶ Check sensor wire connections.
1) 2)
▶ Replace the sensor and/or wire connections, if the
problem persists.
1)
A6 Inlet cold water temperature sensor [20]
disconnected or damaged. ▶ Check sensor wire connections.
1) 2)
▶ Replace the sensor and/or wire connections, if the
problem persists.
1)
A7 Heat exchanger hot water temperature sensor [16]
disconnected or damaged. ▶ Check sensor wire connections.
1) 2)
▶ Replace the sensor and/or wire connections, if the
problem persists.
1)
A8 Outlet hot water temperature sensor [17]
disconnected or damaged. ▶ Check connections or replace sensor.
1) 2)
▶ Replace the sensor and/or wire connections, if the
problem persists.
1)