Combustion noises too loud; rumbling noises
Faults that are not displayed
Worcester Bosch Greenstar 4000 Combi
Remedy
▶ Check the gas type.
▶ Check the gas supply pressure.
▶ Check the flue system; clean or repair if required.
▶ Check the gas/air ratio.
▶ Check the gas valve; replace if required.
This code also applies to: