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Ideal Logic fault L-5

Repeated lockout within 15 minutes

Gas boiler

What it means

Boiler has reset 5 times within 15 minutes, indicating persistent ignition failure. Display will show L-5.

Likely causes

  1. Persistent gas supply failure
  2. Flame sensor contamination or failure
  3. Ignition electrode gap incorrect
  4. Gas valve stuck or faulty
  5. Continuous air in gas line

Where to start

  1. Allow boiler to cool
  2. Check gas supply integrity and pressure
  3. Inspect and clean flame sensor

The full answer, free

  • 2 more checks in order
  • How to put it right, step by step
  • The manual page for this fault (page 31), right under the answer
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Safety: Isolate gas and power before you open the case. If you have been into the gas side, do a tightness test, and a combustion and flue check before you hand back. Gas Safe (UK) or RGI (Ireland) work only.

From the Ideal manual for the Logic. Check the model on the data plate before you order parts.

Other Ideal Logic fault codes