Bosch 830 ES Installation And Operating Instructions Manual page 63

Display Cause
Ionization failure during
operation.
Internal hardware/software
failure.
Ionization error at standby. 1. Loose connection to the flame ionization rod. Verify that the thinner wire leading
Gas leakage error, gas valve
circuit not closing properly.
Table 41 * By installer or service technician only.
830 ES – 6 720 644 936 (2021/08)
Solution
1. Check gas type, fig. 2, page 12.
2. Check three wire connections to ignition group on the lower front of the heat
exchanger are secure.
3. Verify that venting specifications are met. Improper venting may cause premature
failure of the flame sensor rod. See chapter 4.3, page 15.
4. Check gas pressure. See chapter 4.14, page 46.
5. Check and adjust CO2 readings. See chapter 7.4, page 53.
6. Check that the minimum power fan speed has been adjusted to the proper value. See
page 30.
1. Disconnect power supply cord and check the two wire and ground connections on
control board as well as ground connection on heater chassis.
2. Pressing the wrong combination of buttons on the control unit can create confusion
among the microprocessors inside. In this case, the error code should not happen more
than once or twice. Turn off the water heater. Turn water heater back on and try
resetting error code. Use the reset button (
3. Possible defective control unit call Bosch Water Heating for further instructions.
from the control unit is securely connected to the set of electrodes located on the lower
front of the heat exchanger.
2. Flame ionization rod or control unit may be damaged. Contact Bosch Water Heating
for further instruction.
1. Disconnect power supply cord and check wire connections on gas valve and the two
connectors on the control board.
2. Flow water out of a hot water tap above the minimum activation point of 0.5 GPM.
Measure voltage at the gas valve wire plug connection. The voltage should measure
24VDC between the left pair of wires and 24VDC between the right pair of wires when
the unit is operating. If voltage is not proper, contact Bosch Water Heating for further
instruction.
3. Gas valve may be defective, contact Bosch Water Heating for further instruction.
Problem solving
) to reset any error codes.
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