How to Fix Ideal Heating L5 Fault Code (UK)
Ideal Heating showing L5 — 5 resets in 15 min. UK diagnosis, likely spare (PCB) and step-by-step reset.
Ideal Heating
What the code means
L5 on a Ideal Heating indicates 5 resets in 15 min. The boiler locks out to protect the heat exchanger and, on gas faults, to comply with the Gas Safety (Installation and Use) Regulations. Always reset to confirm the code is live, not historical.
Likely spare
The most common fix is the PCB. Check the exploded diagram against the GC number on the data plate before ordering — Ideal Heating revised parts on Ideal Heating units mid-production.
Fix procedure
Full reset. If persists, PCB fault.
Log the fault and reset. If the code returns within 24 hours, escalate to full electrical diagnosis with a manometer and multimeter.
Frequently asked questions
- Can I reset L5 myself?
- You can press the reset button up to 3 times. If L5 returns, the boiler needs a Gas Safe engineer — it is illegal to repair gas components without registration.
- Is the part covered under warranty?
- Ideal Heating standard warranty is 2–10 years depending on model. Registered installations get the full term. Check the sticker inside the case.
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