HVACopediaBosch · Tankless water heater
PA PA water actuator (valve calibration)
What the display is showing
Service menu for calibrating the water valves. MF calibrates the main water valve and BP the bypass valve. Calibration is needed after replacing either valve or the electronic control unit, takes several minutes and needs hot water flowing (bypass calibration needs 0.80 to 1.80 gpm). Wait for the completion message.
Applies to: Greentherm T9800 SE 160/199 and T9900 SE 160/199 tankless water heaters
What to do
- Enter AU Technical Settings, then open PA
- Select MF main valve or BP bypass valve and touch OK
- Open a hot water tap and do not interfere until completion shows
Models that show this code
6 models in Bosch Greentherm T9800 SE, Bosch Greentherm T9900 SE
Other codes on the same units
- FH FH failure history
- HS HS about
- OD OD operation data
- Open Taps Open Taps message during auto adjust
- PE PE appliance type (read-only data)
- SA SA settings menu
- Setpoint display Set temperature shown on touch display
- Solar mode Solar mode indicator
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Source: Bosch Greentherm T9800 SE 160-199 installation 6720816815 (06.2023), 6.7 Water valves calibration p.53; 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.