Remeha E6 Fault Code: Causes, Fixes & Repair Costs
What does the Remeha E6 fault code mean?
The E6 fault code on a Remeha boiler is a safety lockout triggered when the boiler's control system detects a flame signal during a period when no burner operation has been requested — in other words, the boiler thinks it can see a flame even though it has been told to stay off. Because an unexpected flame signal represents a potential safety hazard, the boiler shuts itself down and refuses to restart until the underlying cause is identified and resolved. The fault is most commonly traced back to a faulty PCB (printed circuit board) misreading or generating a spurious flame signal, although a contaminated or degraded ionisation/flame sensor can produce the same symptom. Until the root cause is fixed, any reset will only provide temporary relief.
General guidance only — not a substitute for professional advice, and not certified by a Gas Safe engineer. Always have your specific appliance assessed by a qualified professional. Any gas work must be carried out by a Gas Safe registered engineer. If you smell gas or suspect carbon monoxide, leave the property and call the National Gas Emergency line on 0800 111 999.
Common causes
- Faulty PCB (printed circuit board) Common
The PCB is the boiler's main control unit, responsible for interpreting signals from all sensors including the flame/ionisation sensor. When the PCB develops an internal fault — often due to component ageing, moisture ingress, or power surge damage — it can generate or misread a flame signal even when the burner is completely off. This is the single most common root cause of the E6 lockout on Remeha appliances.
- Contaminated or degraded ionisation/flame sensor Sometimes
The ionisation electrode measures the electrical conductivity of the burner flame to confirm ignition. If the electrode tip becomes coated with carbon deposits, oxidation, or dust (for example from nearby building or renovation work being drawn into the boiler's air intake), it can produce a spurious low-level current that the control board interprets as a phantom flame signal. A physically cracked or worn electrode produces similar results.
- Dirty or loose electrical connections Sometimes
Corroded or poorly seated connectors on the flame sensor wiring harness can introduce stray voltages or resistance changes that mimic a flame detection signal. This is more likely on older appliances or those installed in damp or dusty environments, and may cause the E6 fault to appear intermittently — for instance every time the boiler completes a heating or hot water cycle and the burner shuts down.
- Intermittent gas valve fault Rare
In rare cases a gas valve that is slow to close fully can allow a small residual flame to persist momentarily after the boiler shuts off. If the ionisation sensor correctly detects this residual flame during post-cycle checks, the PCB will correctly log an E6 event. This is uncommon but worth mentioning as it requires gas valve inspection or replacement by a Gas Safe engineer.
How to fix it
- Reset the boiler once or twice DIY safe
Locate the reset button on your Remeha boiler's control panel — on most Avanta and Avanta Plus models this is a dedicated button, sometimes requiring you to hold it for around six seconds. Press and hold until the display responds, then allow the boiler to attempt a restart. If the E6 code clears and the boiler runs normally, monitor it closely over the next few hours. If the fault returns after one or two resets, do not continue resetting as this will not resolve the underlying problem and repeated ignition attempts without a proper fix can cause further wear.
- Check that your gas supply is working DIY safe
Confirm that other gas appliances in your home — such as your gas hob or gas fire — are functioning normally. If they are not, contact your gas supplier rather than an engineer, as there may be a supply interruption in your area. If other appliances work fine, the gas supply to the boiler is unlikely to be the direct cause of the E6 fault, though low gas pressure can sometimes contribute to combustion irregularities.
- Check boiler system pressure DIY safe
Look at the pressure gauge on the boiler's front panel. It should read between 1.0 and 1.5 bar when the system is cold. If the needle is below 1 bar, the system may need topping up via the filling loop — consult your boiler's user manual for the specific procedure for your model. Note that low pressure alone does not cause E6, but correcting it rules out a contributing factor before a Gas Safe engineer visits.
- Do not attempt to inspect or clean internal components yourself Gas Safe engineer
Checking, cleaning, or replacing the ionisation electrode, ignition leads, gas valve, or PCB requires the boiler casing to be removed and involves both gas pipework and high-voltage electrical components. This work must only be carried out by a Gas Safe registered engineer. Attempting it yourself is illegal, unsafe, and will invalidate any remaining warranty or boiler cover.
- Call a Gas Safe registered engineer for diagnosis and repair Gas Safe engineer
A qualified engineer will carry out a full inspection: testing the PCB for fault codes and component integrity, checking the ionisation electrode and its wiring for contamination or damage, inspecting electrical connections throughout the flame detection circuit, and if necessary testing the gas valve closure. Based on their findings they will either clean and reseat components, replace the ionisation electrode, or — most likely with a persistent E6 — replace the PCB. Always ask to see the engineer's Gas Safe ID card before work begins; you can also verify registration at gassaferegister.co.uk.
Parts you may need
- PCB (printed circuit board / main control board) · from £280
- Ionisation / flame sensing electrode · from £35
- Ignition electrode assembly · from £45
- Flame sensor wiring harness / connector · from £25
The exact spare depends on your boiler's GC number (on the data badge). Check this against the part before buying.
Typical repair cost
Expect to pay roughly £300–£600, depending on the underlying cause.
Frequently asked questions
Why does my Remeha boiler keep showing E6 every time it switches off?
This is a tell-tale sign that the ionisation electrode or its wiring is producing a stray signal at the exact moment the burner shuts down — or that the PCB is misinterpreting the sensor reading during the post-burner check cycle. Some users also report this happening when the return-side temperature runs high, which can affect sensor behaviour. Either way, intermittent E6 faults that occur at shutdown rather than at ignition still require a Gas Safe engineer to investigate, as the fault will typically become more frequent or permanent over time.
Can I fix Remeha E6 myself, or do I need an engineer?
The only homeowner actions that are safe and legal are resetting the boiler (once or twice), confirming your gas supply is on, and checking system pressure. Everything else — inspecting the PCB, cleaning or replacing the flame sensor electrode, checking gas valve operation, or testing wiring — must be done by a Gas Safe registered engineer. Working on gas appliance internals without Gas Safe registration is illegal under UK gas safety regulations and extremely dangerous.
How much does it cost to fix Remeha E6 in the UK?
Most people with an E6 fault end up paying between £300 and £600 all-in, depending on region and which component is at fault. A diagnostic call-out typically costs £60–£100 on top of any parts and labour. If only the ionisation electrode and a clean of the connections are needed, the bill can sit at the lower end. A full PCB replacement — the most common outcome — usually costs £450–£700 including labour, as the PCB part alone can be £200–£350 for Remeha models. Prices in London and the South East tend to be 10–20% higher than in the North of England or Wales.
Is it worth repairing a Remeha boiler with an E6 fault, or should I replace it?
If your boiler is under ten years old and otherwise in good condition, a PCB or electrode replacement is almost always worthwhile. If the boiler is older than ten to twelve years, it is worth getting a quote for a new boiler alongside the repair quote — as a rule of thumb, if the repair cost exceeds roughly half the price of a comparable new boiler, replacement often offers better long-term value, particularly given that modern A-rated condensing boilers can significantly reduce annual heating bills.