Problem solving
45
Greentherm T9800 SEO 160/199 | SECO 199 – 6 720 817 281 (2018/12)
A9
Incorrect output power (too low).
▶ Check gas inlet pressure
(
▶ Check water temperature sensors [17][19][20]
and water flow sensor [14] wire connections.
▶ Check sensors resistance and water flow sensor(
section 11) and replace any if it is not according to
specification.
AA
Condensing unit flue gases temperature [16]
above 392 °F (200 °C)
and/or flue gases
temperature [15] above 145 °F (63 °C)
at the
exhaust sensor [15]. Appliance regulates power to
protect against overheating.
▶ Descale appliance (
BB
Fan calibration triggered due to missed ignitions.
▶ Check gas inlet pressure (
▶ Perform gas and air tuning (
BC
Successive fan calibration with similar learned
values.
▶ Check gas inlet pressure (
▶ Perform gas and air tuning (
C1
C2
Flue blockage detected during startup due to
insufficient combustion air.
▶ Reset error (press and hold on/off button for 3
seconds).
If the problem persists:
▶ Check air openings and exhaust opening for
obstructions and reset the error.
▶ Check if the air filter is dirty or clogged, replace it if
needed.
▶ Perform gas and air tuning (
▶ Contact Bosch support line for additional
information and assistance in case of installation in
dusty areas.
C3
Flow sensor [14] does not detect water
recirculation.
▶ Check pump and connections.
▶ Check recirculation circuit for any blockage.
C5
Bypass water valve [8] disconnected or damaged. ▶ Check bypass water valve wire connections.
If the problem persists:
▶ Replace the bypass water valve and/or wire
connections.
▶ After valve replacement, proceed with bypass water
valve calibration (
C7
Fan [2] disconnected or damaged.
▶ Check fan wire connections.
▶ Reset error (press and hold on/off button for 3
seconds)
If the problem persists:
▶ Replace the fan and/or wire connections.
C8
Main water valve [22] disconnected or damaged.
▶ Check main water valve wire connections.
If the problem persists:
▶ Replace main water valve and/or wire
connections.
C9
Barometric pressure sensor damaged.
▶ Reset error (press and hold on/off button for 3
seconds).
If the problem persists:
▶ Replace electronic control unit (ECU).
Display
Description
Solution