Error code
Worcester Bosch Boiler Fault Code C6
Quick answer
C6
Fan, flue, or air pressure sensing problem
First safe action
Check the user manual for any basic external checks the manufacturer allows.
Meaning
Worcester Bosch boiler fault code C6 usually points to a problem with air movement, the fan, or the boiler's ability to confirm safe flue operation.
Likely causes
- Fan fault
- Air pressure sensing issue
- Flue-related restriction or condensate-related effect
Safe first checks
- Check the user manual for any basic external checks the manufacturer allows.
- Do not continue resetting the boiler if the code is persistent.
- If weather-related freezing is suspected on an accessible external condensate pipe, follow only the manufacturer's guidance.
How to reset
- Use the standard user reset only if the manual says it is appropriate.
- Book an engineer if the code stays active.
When to call an engineer
Fan and flue safety faults should be checked by a qualified engineer rather than pushed through with repeat resets.
Safety warning
Do not dismantle flue or fan components, and do not remove the boiler casing.
Useful hub links
Related fault codes
A1 for Worcester Bosch Boiler
Water circulation or pump performance issue
CE for Worcester Bosch Boiler
Fan, flue, or air pressure sensing problem
D1 for Worcester Bosch Boiler
Control board or internal communication fault
EA for Worcester Bosch Boiler
The boiler has failed to ignite properly
296 for Worcester Bosch Boiler
Flame detection has been lost during operation
297 for Worcester Bosch Boiler
Gas supply control or gas valve issue
Relevant guides
Frequently asked questions
Can I keep resetting a Worcester Bosch boiler with C6?+
No. If C6 returns after one standard user reset, stop there and arrange a qualified engineer if the manual gives no safe next step.
Is C6 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.