The A01 Vokera fault code means your boiler has failed to ignite. The boiler is trying to light but cannot complete the ignition sequence, so it shuts down as a safety measure. This is one of the most common Vokera boiler faults and can leave you without heating or hot water.
Some causes are straightforward, while others require a Gas Safe engineer. This guide explains the most common reasons for an A01 fault, the safe checks you can carry out, and when professional repair is the safest option.
If You Smell Gas
If you smell gas at any point, stop what you're doing immediately. Do not attempt any of the checks below, and do not operate light switches or naked flames. Turn off the gas supply at the meter if it's safe to do so, ventilate the area, and call the National Gas Emergency Service on 0800 111 999 straight away.
What Does the A01 Vokera Fault Code Mean?
The A01 error indicates an ignition failure. Gas is not being ignited correctly, so the boiler automatically locks out to prevent unsafe operation. Although the fault should be dealt with promptly, it doesn't always mean a major repair is needed — a temporary interruption to the gas supply or a simple reset may resolve the issue. Persistent faults usually point to a failed component that requires professional diagnosis.
Common Causes of an A01 Vokera Boiler Fault
Common causes include no gas supply, a frozen condensate pipe, a faulty gas valve, a damaged ignition electrode or ignition lead, a faulty flame sensor, or a PCB fault. Each of these prevents the boiler from completing its ignition sequence, causing the boiler to display the A01 code.
Safe Checks You Can Try
Check Your Gas Supply
Check whether other gas appliances are working — if you have a gas hob, see if it lights, and if you use a prepayment meter, make sure there is enough credit. If no gas appliances work, the issue is likely to be your gas supply rather than the boiler itself. If at any point you smell gas, stop checking and follow the gas emergency guidance above instead.
Reset Your Vokera Boiler
If your gas supply is working, try resetting the boiler — press and hold the reset button for 3–5 seconds, or turn the control dial to the reset position if your model uses a dial. Wait several minutes for the ignition cycle to complete before checking whether the fault has cleared.
When You Need a Gas Safe Engineer
If the A01 code returns after a reset, avoid repeatedly restarting the boiler. Professional diagnosis is recommended because the fault may involve any of the following.
Frozen Condensate Pipe
External condensate pipes can freeze during cold weather, preventing the boiler from operating correctly.
Faulty Gas Valve
A defective gas valve can stop gas reaching the burner. Gas valve testing and replacement must only be carried out by a Gas Safe engineer.
Ignition System Faults
Problems with the ignition electrode, ignition lead or flame sensor can all prevent reliable ignition.
PCB Faults
The printed circuit board controls the ignition sequence. When it develops a fault, specialist testing is required before replacing parts. If the fault keeps returning after a reset, our boiler repair in London service can diagnose the cause and carry out a safe repair.
Preventing Future A01 Faults
Regular servicing helps reduce the risk of ignition faults. To help prevent future A01 errors: service the boiler every year, insulate external condensate pipework, keep prepayment meters topped up, and arrange repairs if you notice delayed ignition or intermittent heating. Routine servicing often identifies worn ignition components before they fail completely.
Need Help With an A01 Vokera Boiler Fault?
If your boiler still displays the A01 fault after checking the gas supply and carrying out a reset, it's time for a professional inspection. Serviceteam's Gas Safe engineers diagnose ignition faults across the Vokera range and can identify the underlying cause quickly and safely. If you're seeing a different Vokera error, our Vokera boiler fault codes guide explains what each code means and the checks you can safely carry out before booking a repair.
