UK Appliance Error Codes

Error code

Ideal Boiler Fault Code L6

Flame detection has been lost during operation The most likely cause is intermittent gas supply issue. Check first: try the standard reset once if permitted by the manufacturer.

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

Quick answer

L6: what does it mean and how to fix

high severity

What does it mean?

Flame detection has been lost during operation

How to fix first

Check the boiler manual for any user-level checks allowed for this code.

Why is this happening?

Intermittent gas supply issue

When should I call an engineer?

Repeated flame-loss faults should be assessed promptly by a Gas Safe registered engineer.

What does this error code mean?

Ideal boiler fault code L6 usually means the boiler lit initially or tried to run, but then lost flame detection and shut down for safety.

In practice, L6 is commonly linked to Intermittent gas supply issue, Flame sensing fault, or Combustion or control issue.

Start with this safe check: Check the boiler manual for any user-level checks allowed for this code. If the code returns, the fault worsens, or the appliance does not behave normally, repeated flame-loss faults should be assessed promptly by a Gas Safe registered engineer.

Why is this happening?

  1. Intermittent gas supply issue
  2. Flame sensing fault
  3. Combustion or control issue

How to fix this safely

  1. Check the boiler manual for any user-level checks allowed for this code.
  2. Try the standard reset once if permitted by the manufacturer.
  3. Stop using the boiler if the fault returns repeatedly.

Reset steps

  1. Use only the standard user reset process if the manual allows it.
  2. 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

Ideal appliance error code hub

Browse all Ideal appliance error code clusters.

Ideal Boiler error code list

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Related flame-loss fault codes

Ideal Boiler Fault Code L2

The boiler has lost or failed to prove flame

Ideal Boiler Fault Code F2

Flame detection has been lost during operation

Ideal Boiler Fault Code L5

Control board or internal communication fault

Ideal Boiler Fault Code C0

A boiler sensor is giving an invalid reading

Relevant guide

Boiler Fault Codes: When to Stop and Call a Professional

Boiler issues need a more cautious approach than most white goods, especially where gas, combustion, or repeated lockouts are involved.

Frequently asked questions

Can I keep resetting a Ideal boiler with L6?+

No. If L6 returns after one standard user reset, stop there and arrange a qualified engineer if the manual gives no safe next step.

Is L6 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.