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Worcester Bosch boilers fault codes

Worcester Bosch codes come in two parts and both matter. The letter-and-number pair, such as EA or C6, is the fault category. The three-digit number after it, such as 227 or 224, identifies the exact condition within that category. Quoting only the first half is why so many Worcester diagnoses go round in circles — EA 227 and EA 229 are different faults with different fixes.

Where the code shows on a Worcester Bosch

Greenstar models show the code on the digital display, usually alternating between the letter pair and the three-digit number. Write both down. On models with a service key socket behind the flap, the fault history is readable there.

How to reset a Worcester Bosch

Press and hold the reset button — the one marked with a flame inside a circle, or the button showing a spanner on newer units — for around five seconds until the display clears and the boiler begins its start sequence.

Most common Worcester Bosch faults

The Worcester Bosch codes people look up most.

Every Worcester Bosch fault code

10 published codes. Filtering happens in the page — every code is in the HTML.

Showing 10 of 10 codes

Every published Worcester Bosch fault code with its meaning and severity
CodeWhat it meansSeverity
EA 227The boiler tried to light and never detected a flame, so it has shut the gas off and locked out. This is the most common Worcester fault code.Stop — call an engineer
CE 207System water pressure has dropped too low for the boiler to run safely. Topping the system back up to 1.2 bar usually clears it in five minutes.Get it checked
E9 219The boiler has overheated and the safety thermostat has tripped. Water is not carrying heat away from the exchanger, and it should not be run until that is fixed.Stop — call an engineer
C6 224The fan is not reaching the speed the boiler asked for, so combustion cannot be confirmed as safe and the burner has been prevented from firing.Get it checked
EA 229The burner lit and then the flame was lost during operation. That is a different fault from failing to light in the first place.Get it checked
A1 229The boiler has detected a dry-fire condition — it is trying to heat water that is not moving. Turn it off and leave it off until an engineer has seen it.Stop — call an engineer
C7The fan is not running at all, as distinct from running at the wrong speed. The burner is locked out until it is fixed.Get it checked
F7 228A flame is being detected before the burner has started. Switch the appliance off and get a Gas Safe engineer rather than resetting.Stop — call an engineer
D5The condensate pump has failed or cannot discharge. Acidic water will back up inside the appliance, so it needs attention promptly.Get it checked
E2 222The flow temperature sensor is giving a reading the appliance cannot trust. Usually the sensor rather than the temperature.Get it checked

Worcester Bosch models

Codes can differ between generations. Check yours.

Guides that help with Worcester Bosch faults

Looking for Worcester Bosch’s own support? www.worcester-bosch.co.uk. We are not affiliated with Worcester Bosch.