This fault can involve incomplete combustion and carbon monoxide.
If anyone in the property feels sick, dizzy or drowsy, or you can smell gas: open the windows, leave the building, and do not switch anything on or off. Then call the National Gas Emergency Service.
0800 111 999Baxi E168 fault codewhat it means and how to fix it
Trade lists call E168 a Baxi PCB lockout, but no Baxi UK manual or error-code page prints it. Treat it as a board fault: one power cycle, then an engineer.
Take care
Get a Gas Safe registered engineer to look at your Baxi E168
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 E168 means
E168 is in an awkward position. It is widely quoted on merchants' and installers' lists of Baxi codes, usually as a PCB or general lockout, and this site had a page for it; but it is not printed in the fault table of any Baxi installation manual or user guide read for this site — the Duo-tec Combi HE A, Platinum, Platinum+, Duo-tec 2, 600, 800, Compact, Assure, Megaflo, EcoBlue — and it is not on Baxi's professional error-code page, which lists every code Baxi expect an engineer to meet on those ranges.
The manufacturer is silent on it. That does not mean the display cannot show it: Baxi's boards are shared across BDR Thermea and carry code definitions that the UK tables leave out, and the 600 Combi user guide anticipates exactly this — "if a different error code from those described in the table of error codes appears on the display contact Baxi Customer Support". So the honest position is that E168, where it appears, is one of those undocumented codes. The trade consensus that it is a board lockout is consistent with where it sits in the numbering, beside E160 (fan) and the electronics codes, and with what engineers report clearing it: a power cycle, a board, occasionally a wiring fault upstream of the board. This page therefore gives the safe advice for an unlisted electronics code rather than a manufacturer meaning.
Note the code exactly as displayed and the boiler model; switch the boiler off at the fused spur for a minute and on again, once; and if it returns, or comes with any smell of gas or sign of combustion trouble, stop and call a Gas Safe registered engineer or Baxi Customer Support with the code. It is not a code to reset repeatedly, because a board that is locking out for a reason it will not name may be protecting something that matters.
What causes it
| Cause | What is actually happening | How likely |
|---|---|---|
| PCB internal fault (trade consensus, not Baxi's wording) | The meaning installers and merchants give E168. A board that has failed a self-check or lost stored values. Confirmed only by an engineer, and only by elimination. | Common |
| Supply disturbance | A brownout, a surge or a power cut mid-cycle leaves the board in a state it reports with an undocumented code. Clears with one power cycle and does not return. | Common |
| Wiring or connector upstream of the board | A loose terminal or a chafed lead feeding the board intermittently. Found by an engineer checking the supply and connections before condemning the PCB. | Occasional |
| A code from a non-UK table | The boards are shared across BDR Thermea. The display may be showing a definition Baxi UK did not print, which is why the user guide says to contact Baxi Customer Support for any code not in the table. | Occasional |
Can you fix it yourself?
Stop — this needs an engineer
What it costs to fix
Typical repair cost
£80–£400
Time on site
45 minutes
Diagnosis £80–£150. PCB, if that is the conclusion, £250–£400 fitted.
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.
Baxi / Potterton / Main main PCB
£150–£320Authorised Baxi parts distributor
Price checked 28 September 2026
Own this appliance and had this code? . Nothing is published until a person has read it.
Related Baxi fault codes
- E83Usually simple to fixE83 to E87: the boiler has lost contact with a connected control — a room unit or programmer wired to the board. Check the control first; the boiler itself is usually fine.Related: electronics and power
- E103Get it checkedSafety Assist codes E103, E104 and E107: the battery-backed safety board on the 600 and 800 is exhausted, faulty or out of step with the main board. Contact your installer; there is no reset.Related: electronics and power
- E.02.47Usually simple to fix"Connection to external device unsuccessful": a Baxi 200/400 Combi or Combi 2 has lost a control it was paired with. Check the control and its wiring; Baxi's remedy is the auto-detect function.Related: electronics and power
- E55Get it checked"Calibration Required": the gas valve has not been set up to the board after a PCB or valve change. An engineer's combustion-analyser job, not a fault a householder can clear.Related: electronics and power
- E317Get it checkedMains frequency out of range (shown on some boards as 162). The boiler, not the supply, is almost always the odd one out. Check other appliances, then call an engineer.Related: electronics and power
- E385Get it checkedUnder-voltage (shown on some boards as 165): the supply at the board dropped below what it will run on. Usually a house-wiring or supply problem the boiler is reporting, not causing.Related: electronics and power
Own a Baxi boiler? Save it and its codes come first next time.
Related guides
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 documentation checked — this code is not published in it, and we say so on the page
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.