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Baxi E168 fault code: what it means and what to do
An E168 on the display means your Baxi boiler has locked itself out. It is a general electronic fault, usually tied to the boiler's circuit board, its wiring or its power supply. One reset is worth trying, but if the code comes back it is a job for a Gas Safe registered engineer.
Quick answer
Baxi E168 is a general PCB / lockout fault. The boiler has shut down as a safety precaution, often after a power-supply disturbance or following an earlier fault. The only safe thing you can try yourself is a single reset (or switching the boiler off at its fused spur for a minute, then back on).
If E168 clears and stays away, the lockout may have been a one-off. If it returns, the underlying fault is still there and the boiler needs a Gas Safe registered engineer to diagnose it — this is not a DIY repair.
What does E168 mean on a Baxi boiler?
E168 is a general fault and lockout code on Baxi condensing boilers — it appears on models such as the Duo-tec range and the newer 600 and 800 series. In plain terms, the boiler's electronics have detected something they are not happy with and have shut the boiler down as a safety precaution.
Until the fault is cleared, the boiler will not fire and you will have no heating or hot water.
Unlike a code that points to one specific part (a fan or a pressure sensor, say), E168 is deliberately broad.
It is most often linked to the printed circuit board (PCB) — the boiler's "brain" — to the wiring and connections inside the boiler, or to a problem with the mains electrical supply feeding it.
Because it is a catch-all electronic fault, the code itself does not tell you exactly which part has failed; that takes an engineer's diagnosis.
The most useful thing to know: E168 often appears simply because the boiler reset after an earlier fault or a brief power glitch. So try one reset first. If the boiler runs normally afterwards, you may need nothing more.
If E168 comes straight back, stop and book a Gas Safe engineer — repeated lockouts mean a real fault that only a professional should investigate.
Common causes of Baxi E168
Because E168 is a general lockout, it can be triggered by several things. The most common are:
- A power-supply disturbance — a power cut, a brownout, or mains voltage drifting outside the boiler's tolerance (the supply should sit within roughly 230V give or take about 10%) can trip the boiler into lockout.
- A "hangover" from an earlier fault — the boiler may have flagged a different fault (such as an E20, E28, E110, E119, E133 or E160), and E168 is what shows after it resets itself.
- Loose, corroded or damaged wiring between the boiler's components or boards, disrupting the signals they send each other.
- A problem in the boiler's internal electronics or connections that the control system cannot pin to a single part.
- A faulty PCB — once the simpler causes are ruled out, a failing control board is the usual culprit, and that means a board replacement.
Damp can also play a part: moisture reaching the electronics (for example from a leak elsewhere in the boiler) can cause exactly this kind of intermittent electronic fault.
What you can safely check
E168 is an engineer-only fault. There is nothing inside the boiler you should open, adjust or touch — the PCB, wiring, gas and sealed components are all off-limits to anyone who is not Gas Safe registered. That said, there are a few universal, no-tools checks any homeowner can safely make before calling out an engineer:
- Try one reset. Press and hold the reset button as described in your Baxi user guide, or switch the boiler off at its fused spur (the switch on the wall, not the consumer unit), wait about a minute, then switch it back on. Give it one attempt only — repeatedly resetting a boiler that keeps locking out can do harm and gets you nowhere. See our guide on how to reset your boiler.
- Check there hasn't been a power cut and that other appliances on the same circuit are working. If your home recently lost power, E168 may simply be the boiler recovering.
- Glance at the pressure gauge. While E168 itself is not a pressure fault, it is worth noting the reading (normally around 1–1.5 bar when cold). Our guide on what your boiler pressure should be explains the healthy range, and what to do if pressure is too low.
- Make sure the gas is on — check other gas appliances such as a hob are working, in case the supply has been interrupted.
That is the full extent of safe DIY for E168. Do not remove the boiler casing, and never attempt to work on the gas supply, flue or any electrical component yourself.
When to call a Gas Safe registered engineer
Call an engineer if E168 returns after a single reset, if it keeps locking the boiler out, or if the reset does nothing at all. By law, only a Gas Safe Register engineer may work on the gas supply, burner, gas valve, flue, sealed combustion circuit, PCB or pressure-relief valve. It is illegal and dangerous for an unregistered person to attempt this work.
A competent engineer will typically: confirm the code and read any fault history, check the mains voltage and earthing feeding the boiler, inspect the wiring and connectors between the control boards for damage or corrosion, look for any signs of damp or water ingress on the electronics, and — if everything else checks out — test or replace the PCB.
Because E168 is a general fault, this methodical "rule things out" approach is exactly what is needed; there is no shortcut a homeowner can take.
If you ever smell gas or suspect a leak, do not touch the boiler — leave the property and call the National Gas Emergency line on 0800 111 999 straight away.
Typical Baxi E168 repair cost
The cost depends entirely on what the engineer finds. A loose connection or a wiring fix is cheap; a new PCB is the most expensive realistic outcome. The figures below are indicative 2026 UK ranges including parts, labour and VAT — always get your own quote, as prices vary by region and by your specific Baxi model.
| Job | Indicative 2026 cost |
|---|---|
| Diagnostic / call-out (often deducted from the repair) | £60–£100 |
| Wiring repair or reconnecting a loose connector | £80–£180 |
| Replacement PCB (the likely fix, parts + labour) | £450–£700 |
For context on how these figures compare with other faults, see our overview of boiler repair costs. If the boiler is old and a PCB replacement is needed, it is worth weighing the repair against the cost of a new boiler.
Related Baxi fault codes
Baxi uses a family of E-codes for different faults. If your display has shown something other than E168, these guides may help:
You can also browse the full Baxi fault codes hub for every code explained in one place.
Will boiler cover pay for an E168 repair?
It depends on your policy. A genuine breakdown like an E168 lockout is the kind of fault boiler cover is generally designed for, and many policies would send an engineer to diagnose the fault and contribute towards labour and parts (including a PCB) up to the policy's limits, subject to any excess.
Our guide on what boiler cover includes sets out what is normally covered.
The honest caveats: most policies exclude faults that existed before you took the cover out, may not pay out during an initial waiting period (often the first 14–30 days), and can decline claims on a boiler that has not been serviced or is beyond a certain age.
Always read your own policy terms before you assume a PCB is covered. This is general information, not financial advice — whether a policy makes sense for you depends on your own circumstances, and our look at whether boiler cover is worth it walks through the trade-offs.
Is a Baxi E168 fault dangerous?
The boiler locking itself out is actually a safety feature — it has shut down rather than carry on with a fault present, so the lockout itself protects you. E168 is not a code that signals an immediate gas hazard.
However, the underlying electronic fault should be diagnosed by a Gas Safe engineer, and if you ever smell gas, leave it alone, leave the property and call 0800 111 999.
Can I fix E168 myself?
No, beyond trying a single reset. E168 points to the PCB, wiring or power supply inside the boiler, and only a Gas Safe registered engineer may open the boiler and work on those parts. It is illegal and unsafe for an unregistered person to attempt it.
Will E168 clear on a reset?
Sometimes. If the code appeared after a power cut or a one-off glitch, a single reset may clear it and the boiler will run normally. If it comes straight back, the fault is still there — don't keep resetting; book an engineer instead.
How much does it cost to repair a Baxi E168 fault?
It depends on the cause. A wiring fix might be £80–£180, while a replacement PCB — the most likely fix if the board has failed — typically runs £450–£700 including parts and labour in 2026. Expect a diagnostic or call-out fee of around £60–£100, often deducted from the final bill. Always get your own quote.
Does E168 mean the PCB needs replacing?
Not always. E168 is a general fault, so an engineer will first rule out power-supply problems, loose or corroded wiring and damp before concluding the PCB itself has failed. A board replacement is the likely outcome only once those simpler causes are eliminated.
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Compare boiler coverThis article is general information, not gas-safety or financial advice. Always have gas appliances checked and repaired by a Gas Safe registered engineer. In a gas emergency, call the National Gas Emergency line on 0800 111 999. Costs are indicative UK guides for 2026.