Ideal L E fault codewhat it means and how to fix it
A board error on an Isar, Icos, Mexico HE or Esprit. L E is the locked-out form and H E the temporary one; Ideal try a reset and a power cycle, then replace the PCB.
Take care
Get a Gas Safe registered engineer to look at your Ideal L E
We do not pass enquiries to a repair firm, so there is no form here. Find a Gas Safe registered engineer through the Gas Safe Register, and ask to see their registration card when they arrive — it is the register, not the van, that tells you they are qualified.
What L E means
L E and H E share one frame in Ideal's fault-finding chart, headed PCB Error. The letter is the state: H E is the board reporting an internal problem it may recover from, L E is the same problem after the boiler has given up and locked out. The chart is short. Press and hold the reset button for two seconds — does the boiler operate correctly? If not, turn the boiler off, wait five seconds and turn it on — does it operate correctly now?
If not, "internal fault within the PCB, replace PCB". There is no thermistor to test or wiring to trace, because the board is reporting on itself. What the chart does not say, and what an engineer arriving at a fifteen-year-old Isar knows, is that the primary control board is a known weak point of that generation, and that the V9 board fitted as a replacement behaves slightly differently after overheat resets. Neither the Isar nor the Mexico HE user guide mentions L E at all, so the householder has nothing from Ideal to try beyond the reset every code allows.
What causes it
| Cause | What is actually happening | How likely |
|---|---|---|
| Primary control PCB failed | The end of Ideal's chart and the usual outcome once a reset and a power cycle have not cleared it. Boards of this generation fail with age and heat rather than for a reason anyone can fix. | Common |
| Transient the board could not recover from | A supply dip or a spike leaves the board in a state a power cycle resolves. If H E or L E does not return after Ideal's five-second off-and-on, that is what it was. | Occasional |
| Board damaged by an upstream fault | Water from a leaking component above, or a shorted lead, can take a board out. The engineer checks for the cause before fitting a second board to the same fate. | Rare |
Can you fix it yourself?
Stop — this needs an engineer
What it costs to fix
Typical repair cost
£200–£380
Time on site
45 minutes
A primary control PCB for the Isar, Icos, Mexico HE or Esprit £200–£380 fitted, where one is still obtainable. Nothing if a power cycle clears it, though that should be reported.
Typical UK prices including parts and labour, updated September 2026. Your quote may differ.
Parts you may need
We may earn a commission if you buy a part through one of these links. It does not change what you pay, and it does not affect which parts we list.
Ideal Logic primary PCB
£150–£320Authorised Ideal parts distributor
Price checked 28 September 2026
Own this appliance and had this code? . Nothing is published until a person has read it.
Related Ideal fault codes
- F9Get it checkedThe control board has not been told what boiler it is in, or has failed. L9 is the same fault locked out. The 2011 Logic Combi row also covers a gas valve short circuit.Related: electronics and power
- dUUsually simple to fixNot a fault. The diverter valve has been parked in its mid-position for servicing and the boiler is waiting to be told the service is over. Ideal publish the way out.Related: electronics and power
- Blank displayGet it checkedNothing on the screen at all. Ideal's user guides send you to the boiler's switch and the consumer unit first; the installer charts then work from the terminal block to the board.Related: electronics and power
- F7Get it checkedThe mains voltage reaching the boiler has dropped below what the board will run on. Ideal's advice is an electrician or your electricity supplier, not a heating engineer.Related: electronics and power
- C0Get it checkedThe board cannot activate the Boiler Chip Card that tells it what model it is fitted to. Ideal's engineer check is whether the small plastic card is in its slot at all.Related: electronics and power
- L9Get it checkedOn a Logic, L9 is the locked-out form of the unconfigured-board fault F9. On an Isar HE it is something else entirely: a heat exchanger overheat read by the dry-fire thermistor.Related: electronics and power
Own an Ideal boiler? Save it and its codes come first next time.
Related guides
Common questions about Ideal L E
What is the difference between L E and H E?
Only the state. Ideal's Esprit guide states the rule for this display: H codes are temporary and reset when the condition clears; L codes are permanent and cause a lockout. Both send the engineer to the same PCB Error chart.
Can I try the power cycle myself?
Switching the boiler off at its own switch, waiting five seconds and switching it on is harmless and is the second step in Ideal's chart. It is not in the user guide, so this page does not present it as a fix, but a boiler that comes back and stays back after it has told you something useful to pass on.
Is a new board worth it on a boiler this old?
That is the real question with L E. A PCB for an Isar or Icos is a significant part of the cost of a modern replacement, and the boiler around it is near the end of its life. Get the quote and ask the engineer to be honest about the rest of the appliance.
Technical review
Not reviewed by an engineer
No engineer has read this page. Severity follows what the manufacturer publishes, and we would rather tell you that than let a byline imply a sign-off.
Sources and how we verified this
We establish the facts from the sources below and then write the explanation ourselves. We do not copy manufacturer wording and we do not host their manuals.
- Manufacturer technical and service documentation
This page has not been reviewed by an engineer, and we would rather tell you that than imply otherwise. The severity rating follows what the manufacturer publishes: where they say isolate the appliance and call someone, so do we.