In This Guide
Understanding the Baxi E168 Error Code
E168 is a PCB, or Printed Circuit Board, lockout code. The PCB is the boiler’s central control unit, responsible for managing and regulating pretty much every function the boiler carries out, from ignition sequencing to pump control to reading the various sensors dotted around the system. When the PCB detects something it can’t reconcile, whether that’s an electrical inconsistency, a gas supply issue, or a fault reported by a connected sensor, it locks the boiler out rather than continuing to operate against an unresolved problem.
This is precisely why E168 is often described as a vague or general fault code rather than a specific one. Unlike a code that points directly at a single component, E168 essentially means “the control system has detected something wrong, but the exact source needs further investigation.” That ambiguity is what makes proper diagnosis so important here, rather than assuming the cause based on the code alone.
When E168 appears, the boiler stops working entirely: no heating and no hot water until the fault is resolved. It’s worth being direct about the risk of repeated resets. Switching the boiler off and on again can appear to clear the fault temporarily, particularly if the underlying cause is something transient like a brief power fluctuation, but resetting repeatedly without addressing a genuine underlying issue tends to mask a developing problem rather than fix it. What might have been a straightforward, inexpensive repair if caught early can turn into a more extensive one by the time an engineer eventually gets involved.
Common Causes of the E168 Fault
|
Cause |
What’s happening |
|
Disrupted electrical supply |
A power cut, tripped circuit breaker, or faulty household wiring affecting the boiler’s power input |
|
Gas supply fault |
The gas supply to the boiler is interrupted or restricted, preventing normal operation |
|
Faulty PCB |
The control board itself is damaged, corroded, or malfunctioning internally |
|
Low water pressure |
Insufficient system pressure triggering a lockout as a protective safety response |
|
Failing sensor or thermostat |
A related component sending an inaccurate reading that the PCB interprets as a fault condition |
|
Unstable mains voltage |
Power dips or spikes moving outside the boiler’s normal tolerance range, typically 230V plus or minus 10% |
|
A prior unresolved fault |
Some older Baxi models display a more specific code briefly before settling on E168 as a catch-all |
Several of these causes can present with an identical E168 code on the display, which is exactly why a proper diagnosis matters more than guessing based on the code alone. If you noticed a different, more specific code flash briefly before E168 appeared and stayed, it’s worth mentioning that to whoever diagnoses the fault, since it can meaningfully narrow down where the actual problem sits.
Troubleshooting the E168 Fault
There are two genuinely safe checks worth carrying out before booking an engineer, and it’s worth being clear about where the line sits after that.
Check the power supply
Confirm the boiler isn’t affected by a wider power cut, and check whether a circuit breaker at your consumer unit has tripped. If the power supply looks entirely normal, try a single reset by switching the boiler off and back on, following the reset procedure specific to your model.
Check your pressure gauge
If the reading is low, top it up using the filling loop, following the instructions in your boiler’s manual for the correct procedure and target pressure. Low pressure is a genuinely common and easily resolved contributor to this fault, and it’s worth ruling out before assuming something more serious is wrong. Equally, if the pressure gauge already reads within the normal range, don’t use the filling loop regardless, adding water to an already-correctly-pressurised system creates its own problems rather than solving anything.
Beyond these two checks, it’s important not to go further. Opening the boiler casing to inspect the PCB directly, testing or adjusting the gas valve, or investigating the gas supply yourself are not safe DIY steps under any circumstances. These involve either regulated gas work that only a Gas Safe registered engineer is legally permitted to carry out, or specialist diagnostic equipment that most homeowners simply don’t have access to. Attempting them yourself risks both your own safety and further, more expensive damage to the boiler. If a reset and a pressure check don’t clear the fault, that’s the point to call a Gas Safe registered engineer rather than continuing to investigate further yourself.
Do not simply redecorate over water stains or damp patches. Painting over a damp wall without fixing the source will result in the stain reappearing within weeks.
How Much Does an E168 Repair Cost?
Cost depends entirely on the underlying cause once it’s been properly diagnosed. A pressure top-up or a straightforward reset that resolves the fault is covered within the first hour. A PCB replacement, an electrical wiring fault, or a gas valve issue takes longer to diagnose properly and is quoted separately once the actual cause is confirmed, since PCB replacement costs in particular vary significantly depending on your specific Baxi model and parts availability. 0800 Homefix charges £120 for the first hour’s labour, charged in advance, with any further repair cost confirmed before work begins, so you know exactly where you stand before anything further is carried out. See our boiler repair rates for full pricing.
How 0800 Homefix Can Help
0800 Homefix’s Gas Safe registered engineers diagnose E168 faults methodically rather than assuming it’s automatically the PCB, since PCB replacement is by some distance the most expensive possible outcome and shouldn’t be reached for until cheaper, more common causes have genuinely been ruled out first. That means checking the electrical supply and connections for anything loose or damaged, testing system pressure, inspecting the gas valve and confirming the gas supply is functioning correctly, and checking related sensors and thermostats before ever concluding the PCB itself has failed.
Where the PCB genuinely has failed after proper diagnosis, we source the correct replacement part for your specific Baxi model and fit it, then test the boiler thoroughly afterwards to confirm the fault has actually cleared rather than simply been masked by the reset. If your boiler is still within its manufacturer warranty period, we check the terms before proceeding with any paid work, since some E168 repairs may be covered depending on the cause and the age of the installation.
Preventive Measures and Maintenance
Regular servicing remains the most effective way to prevent an E168 fault developing in the first place. Book an annual boiler service with a Gas Safe engineer, who checks the boiler’s electrical connections for early signs of corrosion or looseness, confirms system pressure sits within the correct range, tests the gas supply, and inspects the PCB itself for any visible signs of wear or damage, catching a developing issue well before it causes a full lockout at an inconvenient moment.
Between annual services, there’s a reasonable amount homeowners can do to reduce the odds of this fault appearing. Keeping the heat exchanger reasonably clean and checking your pressure gauge periodically helps prevent both the low-pressure cause specifically and the general wear that contributes to electrical and component faults over time. It’s also worth genuinely avoiding the habit of repeatedly resetting the boiler every time E168 appears without ever getting the underlying cause looked at, since that pattern consistently turns what would have been a straightforward, cheaper fix into a more involved and more expensive repair by the time an engineer finally sees it.
Helpful Resources
Frequently Asked Questions
How can I reset my Baxi boiler after an E168 fault code?
Turn the boiler off and back on once, following your model’s specific reset procedure. If the fault clears and stays cleared, that’s genuinely the end of it, but if it returns, call a Gas Safe registered engineer rather than resetting repeatedly.
What steps should I take to fix a boiler showing an E168 error?
Is there a way to clear the E168 error without professional assistance?
What does an E168 fault code indicate on a Baxi boiler?
Can 0800 Homefix repair this on the same day?
Spotted the E168 Error on Your Boiler?
0800 Homefix’s Gas Safe engineers cover London and the South East, seven days a week, 365 days a year, with a one-hour emergency response. £120 covers the first hour’s labour, charged in advance, with any further cost confirmed before work starts.
Editorial note
This article is a general homeowner guide. All gas work should be carried out by a Gas Safe registered engineer. If you suspect a gas leak, leave the property immediately and call the National Gas Emergency Service on 0800 111 999.
Spotted Any of These Warning Signs?
Our leak detection specialists cover London and the South East using acoustic detection, thermal imaging and moisture meters — no unnecessary damage, full written report, available 7 days a week.
Editorial note: This article is intended as a general homeowner guide. All plumbing work on supply pipes should be carried out by a qualified, WaterSafe-registered plumber. If you suspect a gas leak, leave the property immediately and call the National Gas Emergency Service on 0800 111 999.
