Error code
Worcester Bosch Boiler Fault Code C6
Fan, flue, or air pressure sensing problem The most likely cause is fan fault. Check first: do not continue resetting the boiler if the code is persistent.
Quick answer
C6: what does it mean and how to fix
What does it mean?
Fan, flue, or air pressure sensing problem
How to fix first
Check the user manual for any basic external checks the manufacturer allows.
Why is this happening?
Fan fault
When should I call an engineer?
Fan and flue safety faults should be checked by a qualified engineer rather than pushed through with repeat resets.
What does this error code mean?
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.
In practice, C6 is commonly linked to Fan fault, Air pressure sensing issue, or Flue-related restriction or condensate-related effect.
Start with this safe check: Check the user manual for any basic external checks the manufacturer allows. If the code returns, the fault worsens, or the appliance does not behave normally, fan and flue safety faults should be checked by a qualified engineer rather than pushed through with repeat resets.
Why is this happening?
- Fan fault
- Air pressure sensing issue
- Flue-related restriction or condensate-related effect
How to fix this safely
- 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.
Reset steps
- 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 fan and flue fault codes
Worcester Bosch Boiler Fault Code EA
The boiler failed to establish a flame
Worcester Bosch Boiler Fault Code A1
The boiler is detecting poor water circulation
Worcester Bosch Boiler Fault Code CE
Fan, flue, or air pressure sensing problem
Worcester Bosch Boiler Fault Code D1
Control board or internal communication fault
Relevant guide
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.