Bosch Greentherm T9900 SE 160 Installation And Operating Instructions Manual page 71

Display Description
FA Gas leakage in the gas path (gas valve or gas
manifold shut-off valves).
FC Touch screen key pressed for more than 20
seconds.
Display reads Power demand lower than appliance minimum
SOLAR but without output power.
existence of solar
thermal system.
Display reads
SOLAR and water
temperature low.
Display shows a red HMI (display) is not communicating with Electronic
X. Control Unit.
High pitch noise Combustion flame with gas in excess or lack of air. ▶ Check if gas type is correct ( section 6.8).
(whistling)
Low pitch noise Combustion flame with air in excess or lack of gas. ▶ Check if gas type is correct ( section 6.8).
with vibration
(rumbling)
1) only to be carried out by qualified contractors.
2) see temperature resistance charts in fig. 67 and 68.
Table 29
Note: If the appliance is locked for safety reasons, information is shown on the display to give more information on the problem.
Once the problem is solved, you may have to reset the error (touch and hold
effect if error is visible on the display.
Greentherm T9900 SE/i – 6 720 813 635 (2019/03)
Solution
▶ Replace the gas valve and/or gas manifold.
▶ After gas valve and/or gas manifold replacement
perform gas and air tuning ( section 8.12).
▶ Release the touch screen key.
▶ Clean the touch screen display.
▶ Increase hot water flow.
▶ increase setpoint temperature.
▶ Reset the appliance by unplugging it for some
seconds (at least 10) and plug it back in.
▶ Replace the HMI (display) and/or wire connections
and/or electronic control unit.
▶ Check gas inlet pressure ( section 4.13).
▶ Perform gas and air tuning ( section 8.12).
▶ Check gas inlet pressure ( section 4.13).
▶ Perform gas and air tuning ( section 8.12).
button for 3 seconds). Error reset will only take
Problem solving
1)
1)
1)
1)
1)
1)
1)
1)
71