ApplianceFaults

Error code

Ideal 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.

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

Quick answer

C6: Fan, flue, or air pressure sensing problem

Severityhigh

Meaning

Fan, flue, or air pressure sensing problem

First safe check

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

Stop if

Stop if the code returns after one safe check or the next step would require internal access.

Who to call

Fan and flue safety faults should be checked by a qualified engineer rather than pushed through with repeat resets.

High severity: escalate quickly if it persists. Keep checks outside the casing and use only a manufacturer-approved reset where the manual allows it.

What does this error code mean?

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.

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?

  1. Fan fault
  2. Air pressure sensing issue
  3. Flue-related restriction or condensate-related effect

How to fix this safely

  1. Check the user manual for any basic external checks the manufacturer allows.
  2. Do not continue resetting the boiler if the code is persistent.
  3. If weather-related freezing is suspected on an accessible external condensate pipe, follow only the manufacturer's guidance.

Reset steps

  1. Use the standard user reset only if the manual says it is appropriate.
  2. Book an engineer if the code stays active.

When to call a heating professional

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

Relevant guide

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.