Control Board Diagnostics - Bosch GWH 715 ES User Manual

Maintenance and service
6.6

Control board diagnostics

1. Turn on/off switch on water heater to off (O) position.
B Press and hold the program '
turning the on/off switch to the on (I) position. The
display will cycle through a startup procedure
including the software version.
B Release the ' ' button when '188' appears on the
display. The display should read 'P2' when the
program button is released. If not, repeat process.
B Press and release the '
panel until the display reads 'P4'. You are now in the
diagnostic mode of the control board.
B When the display reads 'P4', press and release the
' ' button once again and the display should read
'E'.
B Use the ' ' and '
to cycle through different diagnostic modes
available.
B Once in the selected diagnostic mode of your
choice, press and release the '
the diagnostic information.
B EXAMPLE: to read the flow rate in gallons per minute
while the unit is flowing water, cycle to the '3d' mode
and press the ' ' button. A reading of 25 on the
display would indicate the heater is reading a flow
rate of 2.5 gallons/minute.
B Once the information is obtained, press the '
button again to return to the diagnostic mode menu
and scroll to addition diagnostic information.
B To exit the diagnostic mode of the heater, use the
' ' or ' ' button until the display reads 'E'.
B Press the ' ' button once again and the display
should read P4.
2. Turn the on/off switch off (O) and back on (I) again to
return heater to normal function.
38
' button while
' button on the control
' button on the control board
' button to display
Diagnostic menu
E Entry/Exit into sub-modes
Set-point temperature
0d
1d Inlet water temperature (°F)
2d Outlet water temperature (°F)
3d Water flow (gallons/min)
Gas type (LP or NG)
4d
5d Fan speed (Hz)
Burner power (%)
6d
7d Maximum power (kW)
Back flow temperature (°C)
8d
9d Not used, setting 00
Most recent error/failure
1F
2F 2nd most recent error
3F 3rd most recent error
4F 4th most recent error
5th most recent error
5F
6F 6th most recent error
7F 7th most recent error
8F 8th most recent error
9th most recent error
9F
'
10F 10th most recent error
Table 18
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