Potterton E168 Fault Code
The E168 fault is the most common Potterton lockout — the boiler attempted to ignite multiple times but could not establish or confirm a stable flame. Potterton and Baxi share this fault code due to BDR Thermea group engineering. It is the Potterton equivalent of Vaillant F.28, Worcester Bosch E1, and Ideal F1.
What is the Potterton E168 fault code?
The Potterton E168 fault is triggered when the PCB initiates a series of ignition attempts and the ionisation probe does not confirm a stable flame within the permitted window. Potterton boilers typically make three attempts before displaying E168 and locking out. The fault can originate at any point in the ignition chain — gas supply, ignition electrode, ignition lead, gas valve, or ionisation probe — and requires a Gas Safe engineer to diagnose. Because Potterton and Baxi share the BDR Thermea group control platform, the E168 code means the same thing on both brands and ignition components are interchangeable across many models.
What causes the E168 fault?
A closed meter valve, empty prepayment meter, or work on the local gas network starves the boiler. Always test another gas appliance before calling an engineer for E168.
The ceramic insulator cracks or the electrode tip corrodes over time, preventing a consistent spark from reaching the burner.
Combustion deposits on the probe prevent it detecting the flame. The PCB receives no flame signal and locks out — even if ignition was momentarily successful.
Cracked insulation on the high-voltage lead causes the spark to arc to ground. The electrode never receives the spark.
A partially blocked or slow-opening gas valve provides insufficient gas at the burner during the ignition window. The spark fires but the flame cannot establish.
Dust, debris, or limescale deposits in the burner ports prevent even gas flow, resulting in partial or no ignition.
What you can safely check yourself
Turn on a gas hob or fire. If nothing works, the supply is the problem — call your gas supplier or check your prepayment meter.
Ensure the emergency control valve at the meter is fully open (handle in line with the pipe). If it was accidentally knocked closed, open it and reset.
Hold the reset button for 3 seconds. Allow up to 60 seconds for the ignition sequence. If E168 returns, do not reset again — call a Gas Safe engineer.
Do not reset the boiler more than once if the fault code returns immediately. Repeated resets without diagnosis can mask a worsening fault.
What needs a Gas Safe engineer
- Test ignition electrode spark output and replace if degraded
- Clean or replace the ionisation probe
- Inspect and replace the ignition lead if cracking or arcing
- Measure gas inlet and manifold pressure
- Test gas valve opening speed and replace if sluggish
- Clean the burner if carbon deposits are present
- Check flue for backpressure that could prevent ignition
Hard water in South London — Wandsworth, Merton, Lewisham, Lambeth, Southwark, Greenwich, and Bromley — accelerates combustion deposits on the ionisation probe and burner. The calcium-heavy Thames Water supply also contributes to limescale inside the burner assembly on Potterton boilers that miss annual services. E168 is the most frequently booked Potterton fault across Reion's South London callouts, following the same pattern as Baxi E168 in the same area.
How much does a E168 repair cost?
Costs below are UK averages. Reion provides a fixed quote after the £80 diagnostic visit — no obligation to proceed.
How to reset a Potterton boiler showing E168
Confirm gas supply is working by testing another gas appliance.
Check the meter emergency control valve is fully open.
Hold the reset button for 3 seconds.
Wait for the full ignition sequence — up to 60 seconds.
If E168 returns, do not reset again. Call a Gas Safe engineer.
Gas valve replacement is among the more expensive Potterton repairs. On a Gold or Titanium model under 10 years old with no other faults, it is worth doing. Because Potterton shares parts with Baxi, gas valves are readily available. On a boiler over 13 years old with additional age-related concerns, Reion will give a clear repair-vs-replace comparison at the diagnostic visit.
Common questions about the Potterton E168 fault
What does a Potterton E168 fault code mean?
Is the Potterton E168 the same as a Baxi E168?
Can a Potterton E168 fault fix itself?
How long does a Potterton E168 repair take in London?
Why does my Potterton E168 fault keep coming back?
Other Potterton fault codes
Need a Potterton engineer in London?
Reion is Gas Safe registered (919881), based in South London, and available 24/7. Fixed price after the diagnostic visit — no hidden charges.
