Bosch AQUA STAR 2400E LP Installation And Operating Instructions Manual page 40

Troubleshooting
Display Cause
F7 Ionization error at standby.
(part# 8708107020)
FA Gas leakage error, gas valve circuit not
closing properly.
(part# 8707021019)
8E Electronic noise on control unit.
(part# 8707207239)
Table 12
* By installer or service technician only.
40
Solution
1. Loose connection to the flame ionization rod.
Verify that the thinner yellow wire leading from the
control unit is securely connected to the set of
electrodes located at the bottom right-hand side 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 .8GPM. Measure
voltage at the gas valve wire connector. The
connector 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
correct, contact Bosch Water Heating for further
instruction.
3. Gas valve may be defective, contact Bosch
Water Heating for further instruction.
1. Improper resetting of other error codes. Using the
on/off switch or unplugging the power cord to reset
error codes can interrupt
microprocessors inside control unit and show 8E on
the display. Only use the reset button (
any error codes.
2. Possible defective control unit call Bosch Water
Heating for further instructions.
signal between
) to reset
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