9F
Burner lockout
Worcester Bosch Greenstar Heatslave II External
Cause 855 (Blocking)
Burner lock out. Check the burner and fuel supply. Ensure the oil supply is free of contaminants.
Action
Reset
Cause 856 (Blocking)
4 burner lockouts repeated resets. After Four 855 burner lock outs in one demand period, cause code 856 is displayed. After boiler off/on cause code 263 will be displayed, press the reset button to clear this fault. another 4 burner lock resets can be attempted.
Action
Turn boiler off/on
This code also applies to: