Maintenance and service
6.6Control board diagnostics
1.Turn on/off switch on water heater to off (O) position.
2.Press and hold the program ( 
) button while turning the on/off switch to the on (I) position. The display will cycle through a startup procedure including the software version.
3.Release the ' 
' button when '188' appears on the display. The display should read 'P2' when the program button is released. If not, repeat process.
4.Press and release the ' 
' button on the control panel until the display reads 'P4'. You are now in the diagnostic mode of the control board.
5.When the display reads 'P4', press and release the
' 
' button once again and the display should read 'E'.
6.Use the ' 
' and ' 
' button on the control board to cycle through different diagnostic modes available.
7.Once in the selected diagnostic mode of your
choice, press and release the ' 
' button to display the diagnostic information.
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.
8.Once the information is obtained, press the ' 
' button again to return to the diagnostic mode menu and scroll to addition diagnostic information.
9.To exit the diagnostic mode of the heater, use the
' 
' or ' 
' button until the display reads 'E'.
10.Press the ' 
' button once again and the display should read P4.
11.Turn the on/off switch off (O) and back on (I) again to return heater to normal function.
Diagnostic menu
E | Entry/Exit into |
0d | |
1d | Inlet water temperature (°F) |
2d | Outlet water temperature (°F) |
3d | Water flow (gallons/min) |
4d | Gas type (LP or NG) |
5d | Fan speed (Hz) |
6d | Burner power (%) |
7d | Maximum power (kW) |
8d | Back flow temperature (°F) |
9d | Flue gas temperature (°F)1) |
| not used, settting 00 |
|
|
1F | Most recent error/failure |
2F | 2nd most recent error |
3F | 3rd most recent error |
4F | 4th most recent error |
5F | 5th most recent error |
6F | 6th most recent error |
7F | 7th most recent error |
8F | 8th most recent error |
9F | 9th most recent error |
10F | 10th most recent error |
Table 19
1)Available only on model GWH C800 ES
6 720 608 542 | 37 |
