What the E168 code means
E168 applies mainly to older Baxi ranges: the Duo-tec Combi HE, Platinum Combi HE and Megaflo System HE, including their A-rated versions. Unlike most Baxi codes, it does not name a single component. Baxi guidance describes E168 as a code that can mean a number of different things, and groups the causes into four areas:
- An earlier fault. The boiler has previously logged another code, such as E119, E125, E133 or E160, and shows E168 after a reset.
- The electricity supply. The mains voltage reaching the boiler has been more than about 10 percent above or below the 230 volts it needs.
- A faulty component. A part such as the gas valve, ignition electrode, pump, fan, diverter valve or wiring harness is failing or has been affected by water.
- The control board. If everything else checks out, the PCB is the likely cause and may need replacing.
Because it covers so much ground, E168 is best treated as a signal that the boiler needs a proper diagnosis. Repeated resets will not tell you which of these applies.
Common causes of E168
A code that came before it
Many people only notice E168, but the boiler may have shown a different code first. Low pressure, an ignition failure or a circulation fault can all be the real starting point. That is why the first checks below cover pressure and gas.
Power cuts and unstable supply
Voltage dips, surges and frequent power cuts can upset the control board. Problems with the fused spur or wiring feeding the boiler can have the same effect.
Worn or water-damaged parts
A leak inside the boiler, or a part near the end of its life, can cause faults that the board reports as E168.
Control board failure
Duo-tec and Platinum boilers are now well into middle age, and PCB failure is a known cause of E168 on these ranges once other causes are ruled out.
| Cause | Typical sign | Who fixes it |
|---|---|---|
| Low pressure behind the fault | Gauge below 1 bar when cold | You, via the filling loop |
| Gas supply interrupted | Hob not working, meter out of credit | You, or the gas supplier |
| Power supply outside tolerance | Fault after power cuts or electrical work | Electrician or Gas Safe engineer |
| Failing component or water damage | Other codes before E168, leaks, noises | Gas Safe engineer |
| Faulty control board (PCB) | Everything else tests fine | Gas Safe engineer |
Safe checks you can do yourself
- Check the pressure gauge with the heating cool. If it is below 1 bar, top up to 1 to 1.5 bar. Our guide on how to repressurise a boiler explains how.
- Check your other gas appliances work, top up a prepayment meter if needed, and make sure the gas isolation valve under the boiler is open with the handle in line with the pipe.
- In freezing weather, check the condensate pipe outside and thaw it with warm (not boiling) water if it is frozen. See our frozen condensate pipe guide.
- Check the fused spur is on and whether there has been a recent power cut or electrical work.
- Press reset as your manual describes, no more than two or three times.
- If a different code appears after the reset, write it down and look it up, for example E133 or E119.
Do not remove the casing or try to check the board, wiring or components yourself. If you smell gas, do not reset the boiler. Turn off the gas at the meter if it is safe, open windows and call the National Gas Emergency Service on 0800 111 999.
When to call a Gas Safe engineer
If E168 returns after the checks above, book a Gas Safe registered engineer. A good engineer will read the fault history, test the supply voltage, and check components such as the gas valve, electrodes, pump and fan before deciding the board is at fault. That order matters, because a new PCB will not fix E168 if a failing part is the real cause.
When you book, give the exact model, the code, any other codes you have seen and whether there have been power cuts or leaks. It helps the engineer bring the right parts and avoids a second visit.
Repair or replace?
Many Duo-tec and Platinum boilers showing E168 are well over ten years old. A board replacement can still be good value on a boiler that is otherwise sound and has been serviced every year. On a boiler that has needed several repairs recently, or where other parts are clearly worn, it is worth asking the engineer for a repair quote and a rough replacement price so you can compare them. A reputable engineer will give you both without pressure.
Typical repair costs in the UK
Typical ranges only. Costs vary with the model, parts availability and your area.
| Job | Typical UK cost |
|---|---|
| Engineer call-out and diagnosis | Typically £80 to £150 |
| Control board (PCB) replacement | Typically £300 to £500 fitted |
| Ignition electrode replacement | Typically £100 to £180 |
| Fan replacement | Typically £200 to £400 fitted |
| Gas valve replacement | Typically £250 to £450 |
On an older Duo-tec or Platinum, a board plus other parts can add up. Ask for a written quote and weigh it against the age and condition of the boiler.
How to stop E168 coming back
Keep the pressure at 1 to 1.5 bar when cold and fix leaks quickly, as water inside the boiler is a common trigger for board and component faults. Deal with any other code as soon as it appears rather than resetting repeatedly. A yearly service lets an engineer spot worn parts early. Our boiler service cost guide explains what is involved.