Vokera 01 Fault Code: Causes, Fixes & Repair Costs
What does the Vokera 01 fault code mean?
The Vokera A01 fault code (also displayed as fault code 10 on some Linea models) means the boiler attempted to light the burner after a heat demand but failed to establish a flame within the expected timeframe. As a safety precaution, the control board shuts the boiler down to prevent unburned gas from accumulating. The boiler will not restart until the underlying cause is addressed and the unit is reset. In plain terms: the boiler tried to ignite, got no confirmation of a flame, and locked out.
General guidance only — not a substitute for professional advice, and not certified by a Gas Safe engineer. Always have your specific appliance assessed by a qualified professional. Any gas work must be carried out by a Gas Safe registered engineer. If you smell gas or suspect carbon monoxide, leave the property and call the National Gas Emergency line on 0800 111 999.
Common causes
- Interrupted gas supply Common
If the gas supply to the property has been disrupted — whether due to a network outage, a closed isolation valve, or a prepayment meter that has run out of credit — the boiler cannot ignite. Check that other gas appliances such as a hob or gas fire are working normally, and verify the meter has credit if you are on a prepayment tariff.
- Faulty or degraded ignition electrode Common
Over time the ignition electrode tip erodes from a flat square end to a pointed one, reducing its ability to generate a reliable spark. Dirty or carbon-coated electrodes have the same effect. A worn electrode can produce a weak spark that fails to ignite the gas consistently, triggering the A01 lockout.
- Blocked or frozen condensate pipe Common
During cold weather the condensate pipe that carries acidic waste water outside can freeze solid, causing the boiler to shut down. Although the boiler typically shows its own condensate fault in this situation, a frozen condensate pipe can also prevent ignition in some Vokera models and is worth ruling out in winter.
- Low system pressure Sometimes
Vokera boilers generally require a system pressure of 1–1.5 bar to operate correctly. If the pressure gauge reads below 1 bar the boiler may refuse to fire, producing the A01 code. Check the pressure gauge on the front of the boiler and top up via the filling loop if needed.
- Faulty ignition lead Sometimes
The high-voltage lead connecting the control board to the electrode can crack, corrode at its connectors, or develop insulation faults. A damaged lead may deliver insufficient energy to fire the spark, causing repeated ignition failure even when the electrode itself is in good condition.
- Gas valve fault Sometimes
The gas valve controls the flow of gas to the burner. If it is stuck closed, no gas reaches the burner regardless of whether the spark is working. Less commonly, a valve that does not fully close can also cause ignition instability. Either condition will result in an A01 lockout and requires a Gas Safe engineer to test and replace.
- PCB (printed circuit board) fault Rare
The PCB orchestrates the entire ignition sequence — it signals the gas valve to open, fires the spark, and monitors the flame sensor. If the PCB sends incorrect signals or fails to interpret feedback from the flame sensor properly, the boiler will lock out with an A01 even when all other components are functioning. PCB faults are relatively expensive to repair and more common on older appliances.
How to fix it
- Check your gas supply and meter DIY safe
Before doing anything else, confirm that other gas appliances in your home — a gas hob, gas fire, or gas oven — are working. If nothing gas-powered is working, you likely have a supply issue: check that the gas isolation valve (the lever on the incoming gas pipe, usually near the meter) is in the open position (inline with the pipe). If you have a prepayment meter, check your credit balance immediately. If neighbours are also without gas, contact your gas network operator.
- Check and top up boiler pressure if needed DIY safe
Look at the pressure gauge on your Vokera boiler — it should read between 1 and 1.5 bar when the system is cold. If it reads below 1 bar, top up the pressure using the filling loop (usually a flexible silver braided hose with one or two valves beneath the boiler). Open the valve(s) slowly, watch the gauge, and close them again once you reach about 1.2 bar. Never pressurise above 1.5 bar. If the pressure drops again quickly after topping up, you may have a leak and should call an engineer.
- Thaw a frozen condensate pipe if the weather is cold DIY safe
If outdoor temperatures are below freezing, your condensate pipe — the white plastic pipe that exits the boiler and runs outside — may be frozen. You can pour warm (not boiling) water over the external section of the pipe, or wrap it with a warm damp cloth. Once thawed, reset the boiler. Consider lagging the pipe to prevent a recurrence.
- Reset the boiler (once or twice only) DIY safe
Once you have completed the checks above, wait at least two minutes before attempting a reset. On Vokera models with a dedicated reset button (such as the Mynute or Easi-Heat), press and hold the button labelled 'R' for approximately 3–5 seconds until the fault code stops flashing, then release and allow the boiler to attempt a restart. On dial-operated models such as the Linea or Compact, turn the selector dial to the RESET or OFF position, hold for a few seconds, then return it to the normal operating position. Do not reset the boiler more than two or three times in total — repeated resets without fixing the root cause can damage components.
- Have a Gas Safe engineer inspect the ignition components Gas Safe engineer
If the boiler locks out again after resetting, a Gas Safe registered engineer should carry out a full inspection. They will typically start by testing the flame sensor to confirm it is accurately detecting — or failing to detect — a flame. Next they will check the ignition electrode for wear and the ignition lead for continuity and insulation integrity using a multimeter. Both components can be replaced at relatively modest cost if found to be defective.
- Have the gas valve tested or replaced if ignition components are sound Gas Safe engineer
If the electrode, lead, and flame sensor are all in order, the engineer's attention will turn to the gas valve. They will test whether the valve is opening correctly when signalled to do so. A faulty gas valve must only be handled by a Gas Safe engineer and should be replaced rather than repaired.
- Have the PCB assessed as a last resort Gas Safe engineer
If all other components have been ruled out, the PCB may be sending incorrect ignition signals or misreading flame sensor feedback. An engineer can test board outputs with a multimeter. Given that PCB replacement on a Vokera boiler can cost several hundred pounds, it is worth asking the engineer whether the age and overall condition of the boiler makes replacement more economical than a PCB repair at this stage.
Parts you may need
- Ignition electrode · from £25
- Ignition lead (HT lead) · from £20
- Flame sensing electrode · from £25
- Gas valve · from £120
- PCB (printed circuit board) · from £220
The exact spare depends on your boiler's GC number (on the data badge). Check this against the part before buying.
Typical repair cost
Expect to pay roughly £150–£350, depending on the underlying cause.
Frequently asked questions
Can I fix a Vokera A01 fault myself?
You can safely carry out a handful of checks — confirming the gas supply is on, checking a prepayment meter has credit, topping up system pressure to 1–1.2 bar, thawing a frozen condensate pipe in cold weather, and resetting the boiler once or twice. Beyond that, any work on the ignition components, gas valve, or PCB must be carried out by a Gas Safe registered engineer. It is a legal requirement in the UK that gas work is performed by a qualified and registered professional.
Why does my Vokera boiler keep showing A01 even after I reset it?
If the A01 fault code returns each time you reset the boiler, a straightforward reset is not going to solve the underlying problem. The most common reasons for a repeat A01 are a worn ignition electrode, a damaged ignition lead, or a faulty flame sensor. Less commonly the gas valve or PCB is at fault. Stop resetting the boiler after two or three attempts and arrange for a Gas Safe engineer to diagnose and repair it — repeated resets without a fix can cause additional wear.
My boiler shows fault code 10, not A01 — is it the same problem?
Yes. On Vokera Linea models the same ignition failure fault is typically displayed as code 10 rather than A01. The meaning, causes, and recommended fixes are identical. If your Vokera model shows a numeric code you do not recognise, always cross-reference with your boiler's manual, as code numbering can vary slightly between models and production years.
How much does it cost to fix a Vokera A01 fault?
Most A01 repairs fall in the range of £150–£350, which typically covers a Gas Safe engineer's call-out, diagnosis, and replacement of the ignition electrode or lead — the most common causes. A gas valve replacement will usually sit toward the higher end of that range. PCB replacement is the expensive exception: parts alone can run to £200–£300 or more, and with labour the total can exceed £450–£500. On an older Vokera boiler, it is worth getting a frank assessment from your engineer about whether a PCB repair makes financial sense versus investing in a new boiler.