UK Appliance Error Codes

Error code

Ideal Boiler Fault Code C6

Last updated: 2 April 2026Boiler faults need a cautious approach

Quick answer

C6

high severity

Fan, flue, or air pressure sensing problem

First safe action

Check the user manual for any basic external checks the manufacturer allows.

Meaning

Ideal 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

Relevant guides

Frequently asked questions

Can I keep resetting a Ideal 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.