BoilerFaultCodes.com

Worcester Bosch Greenstar Utility 18/25 Fault Codes

RegularOil Oil 18-25 kW 2007-2022 Discontinued
GC Number: 41-311-73

Replaced by: Greenstar Utility 18/25 (ERP)

The fault code is already on your display

Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →

Most common fault codes

72
Wind or air is blowing back down your boiler's chimney, which is preventing the exhaust fumes from escaping safely.
Gas Safe engineer required · £120-450
73
Your boiler's internal pump or motor is not receiving power or has stopped working, meaning it cannot circulate heat through your system.
Gas Safe engineer required · £180-£450
74
Your boiler's internal computer has encountered an error and is unable to communicate properly with the rest of the system.
Gas Safe engineer required · £250-500

All 12 fault codes

Code Severity Plain English
72 Emergency Wind or air is blowing back down your boiler's chimney, which is preventing the exhaust fumes from escaping safely.
73 High Your boiler's internal pump or motor is not receiving power or has stopped working, meaning it cannot circulate heat through your system.
74 High Your boiler's internal computer has encountered an error and is unable to communicate properly with the rest of the system.
75 High Your boiler’s internal flame sensor is dirty and can no longer see the fire, causing the system to shut down for safety.
76 High Your boiler's main control board has detected a setup error, meaning it no longer recognises which specific model it is meant to be.
77 High Your boiler has run out of fuel or the oil cannot flow from the storage tank to the burner.
78 High Your boiler is having trouble creating the spark or flame needed to start up because the internal ignition components are out of alignment.
79 High Your boiler has lost its electrical supply and won't turn on, meaning it cannot provide any heating or hot water.
A7 Medium Your boiler is experiencing a communication problem with its internal temperature sensor, causing it to shut down unexpectedly from time to time.
BC High Your boiler has shut down because it is not burning fuel efficiently or safely, which is usually caused by a faulty internal sensor or an incorrect gas mixture.
Boiler overheat thermostat High Your boiler has become too hot and has automatically shut itself down to prevent damage or safety issues.
C6 High Your boiler has stopped working because the fan cannot properly push exhaust fumes out or pull fresh air in through the flue pipe.

Worcester Bosch Greenstar Utility 18/25 is discontinued — time for a new one?

Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.

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