Vokera Boiler Fault Codes: Full List

Work behind the boiler casing is gas work, restricted under HSE gas safety guidance. Vokera has used several control platforms across its range, so the exact code set depends on your model. What does not change is the category a code falls into, and that determines whether it is something you can deal with.

For other brands, see our multi-brand fault code guide and our Glow-worm list.

Pressure Faults

Low water pressure

Commonly shown as a pressure symbol, or a code in the A or F range depending on model. The system has dropped below the minimum and the boiler has shut down.

You can fix this. Repressurise to 1 to 1.5 bar cold using the filling loop — see repressurising a boiler. Recurring pressure loss means a leak; our guide to a boiler losing pressure covers finding it.

Ignition Faults

Ignition lockout / no flame detected

The most common lockout on any boiler. The unit tried to fire and did not detect a flame.

Before calling anyone, check three things:

• Do other gas appliances work? If not, the supply is the issue.
• Is the condensate pipe frozen? Very common in cold weather — see frozen condensate pipes.
• Is the system pressure correct?

Reset once. If it locks out again, the fault is real — a worn electrode, a failed flame sensor or a gas valve issue — and needs an engineer.

Flame loss during operation

It lit and then went out. Similar causes, plus flue and recirculation problems. Engineer required.

Overheat

Overheat cut-out

The boiler exceeded its safe temperature and shut down. Usually restricted circulation rather than a boiler fault — a seized pump, closed radiator valves, or sludge.

Check radiator valves are open and pressure is normal. Repeated overheat lockouts point at flow restriction, which our guide to kettling and sludge explains.

Fan and Flue

Fan or air pressure switch fault

The fan is not reaching the expected speed, or the air pressure switch is not confirming flow. Since the fan clears combustion products through the flue, the boiler will not fire without it.

This is a safety interlock doing its job. Engineer required, and a flue blockage is one possible cause — our guide to boiler flue regulations covers what a flue must satisfy.

Sensor Faults

NTC / temperature sensor fault

A flow, return or hot water sensor reading out of range, or a wiring fault. Inside the casing, so engineer work.

These sometimes present as odd behaviour rather than a hard lockout — hot water that runs too hot or too cold, or heating that cuts out early.

Condensate Faults

Condensate blockage

Some models detect a blocked condensate route directly. In cold weather this is nearly always ice in the external section of the pipe rather than a fault in the boiler.

Thawing it with warm water along the exposed run usually restores operation. If it recurs every winter, the pipe run should be reworked — larger bore, better insulated, or rerouted internally.

What You Can Safely Do

• Repressurise on a low pressure fault.
• Thaw the condensate pipe in cold weather.
• Check radiator valves are open on an overheat fault.
• Reset once.
• Anything requiring the casing to come off is a Gas Safe registered engineer's job. It is illegal otherwise, not merely inadvisable.

Finding Your Model's Codes

Because the code set differs between platforms, the manual for your specific model is the authority. The model name is usually on a label behind the front panel flap or on the underside of the casing.

If you cannot find the manual, the model and serial number are enough for an engineer to identify the code before attending.

Frequently Asked Questions

Can I keep resetting a lockout?

No. Once. A lockout that returns is reporting a genuine fault, and repeatedly clearing an ignition fault is specifically unsafe.

Why does my boiler lock out only in cold weather?

Almost always a frozen condensate pipe. It is the single most seasonal boiler fault there is.

Are Vokera boilers hard to get parts for?

Parts are available, though not as ubiquitous as the largest brands. On older models availability can be a factor in the repair-or-replace decision.

The display shows a code but the boiler works.

Some codes are informational rather than faults. Check the manual for your model — if the boiler is heating normally, it may be reporting status rather than a problem.

If the Code Persists

Once pressure and condensate are ruled out, the remaining causes are inside the boiler. We cover Milton Keynes and the surrounding area for boiler repair. Get in touch with the code and your model number.