How to Fix / Troubleshooting

Safety: Turn off power and gas before opening combustion components. Gas adjustments must be done by licensed personnel.

Verify setpoint: Check the user interface and confirm that the DHW temperature setpoint is correctly set.
Check for scale: Inspect the heat exchanger for scale buildup. If present, perform a chemical descaling according to Buderus instructions.
Clean burner: Remove and clean the burner head to ensure all ports are open.
Gas pressure and modulation: Have a technician measure gas pressures and verify that the gas valve modulates correctly across the firing range.
Re-test: After cleaning and adjustments, run the heater at full demand and confirm that outlet temperature reaches the setpoint.

Water heater produces lukewarm water only; temperature never reaches the setpoint.

Possible Causes