Worcester Bosch Boiler Issues: Errors and Fault Codes
When your Worcester Bosch boiler starts to play up, it can be difficult to know whether the fault is simple to fix or whether it’s a serious issue that requires urgent attention from an engineer. The majority of the time, your Worcester Bosch boiler will shut down or display a unique fault code or an error message to let you know that something isn’t right. Fault codes are designed to make it easy for your engineer to identify the possible cause of a fault, and you may be asked for the code when you call an engineer for assistance.
Your Worcester Bosch boiler manual should list the fault codes and error codes that could appear on your boiler. If you have misplaced your manual and your boiler is displaying a fault code, you can search through our tables below to find out what the error message means.
Worcester Bosch Boiler Fault Codes by Type
Codes That Will Appear On Your Boiler
The boiler will stop operating but no fault code will appear. You can access the cause code by pressing the spanner/return button. The condition will clear once the fault clears. For instance, if the boiler is waiting for an area to cool, the error will clear automatically once the associated area has cooled down.
The boiler will flash a warning triangle and a fault code. It will also show a static cause code. You’ll need to press the boiler reset button to clear the code, but only after the boiler has been fixed.
The boiler will display an alphanumeric fault code to indicate the fault group.
A three-digit number that can be accessed via the info menu by pressing the spanner/return button during a blocking error or when in normal operating status. The cause code should flash on the display during a locking error.
A maintenance code is displayed with the letter H followed by a number. The fault won’t stop the boiler from working but it tells you that the boiler needs to be looked at by a qualified engineer.
Worcester Bosch Boiler Locking Error Codes
Incorrect Heat Control Module (HCM) has been fitted
Code plug is faulty or not connected
Need to replace control board
Fan running too fast
Fan running too slow
Fan not running at all
Fan not running or the airflow is blocked
Sensor wet or damaged – the boiler will usually block for 300 seconds before the fault code is displayed
Sensor is disconnected or damaged – the boiler will usually block for 300 seconds before the fault code is displayed
Flow sensor shorted or damaged
Flow sensor damaged or disconnected
218 or 332
Primary flow sensor overheated
Main heat exchanger overheated
Maximum temperature sensor on main heat exchanger has failed
Maximum temperature sensor on main heat exchanger not recognised
Flue gas thermostat overheated
Failure of four ignition attempts – Need to wait at least 30 seconds before another attempt is made
Established flame has been extinguished – Could be caused by a blocked sump or strong wind into the flue
Gas valve coil disconnected
No flame established during the first 4 seconds of ignition period
Pump not detecting water – check pressure gauge and re-pressurise to 1 bar
Worcester Bosch Boiler Blocking Fault Codes
Low or no water in the system – check pressure gauge and re-pressurise to 1 bar
Fan stopped working
No flame detected – boiler will block during 4 attempts before going to a locking fault
Boiler operating at minimum burner load and there is a greater flow and return temperature than 18°C
212 or 213
Airlock or reduced water content – check pressure gauge and re-pressurise to 1 bar
Sensor disconnected or no water content – check pressure gauge and re-pressurise to 1 bar
 British Gas acts as a credit broker, not the lender and offers products from a panel of lenders. Payment options are subject to change without notice. British Gas is a trading name of British Gas New Heating Limited (No. 06723244), an appointed representative of British Gas Services Limited (No. 03141243) which is authorised and regulated by the Financial Conduct Authority (Financial Services Register No. 490568). Both companies registered in England and Wales. Registered office: Millstream, Maidenhead Road, Windsor, Berkshire SL4 5GD. Availability of credit depends on status and credit checks. Terms and Exclusions apply.
 £100 additional discount is only available to British Gas energy and British Gas HomeCare 1-4 customers who choose to have a British Gas installation. This offer is available to homeowners and landlords with a total system output of up to 50kW who already have a British Gas energy tariff or HomeCare 1-4 at the property where the boiler would be installed. Available to 98% of UK mainland households. This offer cannot be used by tenants, British Gas multi–premise landlord customers and cannot be used in conjunction with staff/ex-staff/partner discounts. Terms and Exclusions apply. Offers are subject to change without notice.
 Saving when upgrading from a G-rated boiler to an A-rated boiler in a detached home using the average energy bill for a high usage house. Source: http://www.energysavingtrust.org.uk/home-energy-efficiency/boiler-replacement and https://www.britishgas.co.uk/energy/guides/average-bill.html
British Gas is a trading name of British Gas New Heating Limited (No. 06723244), an appointed representative of British Gas Services Limited (No. 03141243) which is authorised and regulated by the Financial Conduct Authority (Financial Services Register No. 490568). Both companies registered in England and Wales. Registered office: Millstream, Maidenhead Road, Windsor, Berkshire SL4 5GD. Availability of credit depends on status and credit checks. Terms and Exclusions apply. Saving when upgrading from a G-rated boiler. Source: http://www.energysavingtrust.org.uk/home-energy-efficiency/boiler-replacement