Bosch · Tankless water heater

P4 P4 Information menu

Menu / mode display Bosch Greentherm T9800 SEBosch Greentherm T9900 SE

What the display is showing

Main information menu of the touch display. Items inside it: DH (burner counters), OD (live readings), FH (stored errors), AC (usage estimate) and HS (version info). The other top-level menus are SA settings, AU technical settings (service mode) and P9 purge.

Applies to: Greentherm T9800 SE 160/199 and T9900 SE 160/199 tankless water heaters

What to do

Touch the menu symbol to open Information / Adjustments; the display shows P4 Information
Touch the up or down symbols to scroll between menus
Touch the return symbol to go back to the main screen

Models that show this code

6 models in Bosch Greentherm T9800 SE, Bosch Greentherm T9900 SE

Greentherm T9800 SE 160Greentherm T9800 SE 199Greentherm T9800 SEC 199Greentherm T9900 SE 160Greentherm T9900 SE 199Greentherm T9900 i 199

Other codes on the same units

F3 Control unit internal error / configuration
F7 Control unit internal error
F8 Control unit internal error
F9 Gas valve driver fault
P9 P9 purge menu
AA Flue gas temperature too high, power limited
AC AC consumption
AD Power derate warning

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Source: Bosch Greentherm T9800 SE 160-199 installation 6720816815 (06.2023), 6.5 Information / Adjustments menu pp.47-48; T9900 SE 160-199 installation 6 720 813 635 (2024-06) same section. Summarized in our own words; check the original manual for your model.

For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.