Error code
Worcester Bosch Boiler Fault Code 233
Quick answer
233
Flame detection has been lost during operation
First safe action
Check the boiler manual for any user-level checks allowed for this code.
Meaning
Worcester Bosch boiler fault code 233 usually means the boiler lit initially or tried to run, but then lost flame detection and shut down for safety.
Likely causes
- Intermittent gas supply issue
- Flame sensing fault
- Combustion or control issue
Safe first checks
- Check the boiler manual for any user-level checks allowed for this code.
- Try the standard reset once if permitted by the manufacturer.
- Stop using the boiler if the fault returns repeatedly.
How to reset
- Use only the standard user reset process if the manual allows it.
- Arrange professional diagnosis if the flame fault returns.
When to call an engineer
Repeated flame-loss faults should be assessed promptly by a Gas Safe registered engineer.
Safety warning
Do not attempt internal gas or combustion repairs. Persistent flame faults are not a DIY job.
Useful hub links
Related fault codes
229 for Worcester Bosch Boiler
The boiler has overheated or hit a high temperature limit
232 for Worcester Bosch Boiler
Flame detection has been lost during operation
268 for Worcester Bosch Boiler
Water circulation or pump performance issue
296 for Worcester Bosch Boiler
Flame detection has been lost during operation
227 for Worcester Bosch Boiler
System water pressure is too low
281 for Worcester Bosch Boiler
A boiler sensor is giving an invalid reading
Relevant guides
Frequently asked questions
Can I keep resetting a Worcester Bosch boiler with 233?+
No. If 233 returns after one standard user reset, stop there and arrange a qualified engineer if the manual gives no safe next step.
Is 233 something I can repair myself?+
Boiler faults should be treated cautiously. Stay within the user checks in the manual, and leave gas, combustion, and internal boiler repairs to a qualified professional.