Vokera E080 Fault Code: Causes, Fixes & Repair Costs
What does the Vokera E080 fault code mean?
The E080 code on a Vokèra boiler signals that the boiler's control system has detected a problem with the flue thermistor — the sensor responsible for monitoring the temperature of exhaust gases as they leave the appliance. Either the thermistor has reported an out-of-range reading, or the exhaust gases have reached an unsafe temperature, prompting the boiler to shut down as a precaution. E080 sits within a cluster of related flue and sensor fault codes on the Vokèra Vision Plus range, alongside E084, E086, E090, and E091. Because flue integrity directly affects how safely combustion gases leave your home, the boiler treats this as a lockout and will not restart until the underlying problem is resolved.
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
- Faulty or degraded flue thermistor (NTC sensor) Common
The NTC thermistor that measures exhaust gas temperature can fail gradually through age and heat cycling, or abruptly due to a manufacturing defect. When its resistance drifts outside acceptable limits, the PCB interprets the signal as an error and locks the boiler out. This is the single most frequent cause of E080.
- Loose, corroded, or damaged wiring to the thermistor Common
Even if the sensor itself is sound, a poor connection between the thermistor and the PCB — caused by a corroded connector, chafed wire, or a plug that has worked loose — will produce an erratic or absent signal that the boiler reads as a fault.
- Flue blockage or restriction causing overtemperature Sometimes
A blocked or partially obstructed flue terminal — from a bird's nest, debris, ice, or windblown material — can cause exhaust gases to back up. The resulting heat build-up around the sensor may then push the temperature reading into the lockout range, triggering E080.
- Boiler fan not expelling exhaust gases correctly Sometimes
If the fan is running below its intended speed, has worn bearings, or has failed intermittently, flue gases are not vented efficiently. This can cause localised heat to accumulate near the thermistor, prompting the overtemperature condition.
- PCB fault Rare
In a minority of cases the control board itself is unable to correctly read or process the thermistor signal, even though the sensor and wiring are intact. PCB failure is relatively uncommon and is usually diagnosed only after the sensor and wiring have been confirmed good.
How to fix it
- Check your gas supply is working DIY safe
Confirm that other gas appliances in your home — hob, gas fire — are working normally. If there is no gas supply, contact your gas supplier rather than investigating further.
- Inspect the flue terminal from outside for obvious obstructions DIY safe
Go outside and look at the point where the flue exits the wall or roof. If you can see debris, a bird's nest, or ice blocking the terminal, carefully clear it from outside if it is safe to reach. Do not attempt to work on the flue pipework itself.
- Reset the boiler once or twice DIY safe
On Vokèra boilers, move the mode selector to the OFF/RESET position, then move it back to your preferred mode (hot water only, or heating and hot water). Allow the boiler a minute to restart. If E080 clears and the boiler runs normally, monitor it for recurrence. Do not reset more than two or three times — repeated resets without resolution can mask a worsening fault.
- If the fault returns, stop resetting and call a Gas Safe engineer Gas Safe engineer
A recurring E080 means the underlying problem has not gone away. Continuing to reset without a proper diagnosis risks the boiler overheating or flue gases not being vented safely. At this point, only a qualified professional should work on the appliance.
- Gas Safe engineer: test the flue thermistor with a multimeter Gas Safe engineer
The engineer will disconnect the thermistor and measure its resistance at ambient temperature, comparing the reading against the manufacturer's specification. A reading outside range confirms sensor failure and the part should be replaced with a like-for-like Vokèra-compatible thermistor.
- Gas Safe engineer: inspect and test all wiring and connectors Gas Safe engineer
Using a multimeter, the engineer will check continuity of the wiring loom between the thermistor and the PCB, and visually inspect connectors for corrosion or heat damage. Damaged wires are repaired or replaced and connectors cleaned or renewed.
- Gas Safe engineer: inspect the flue system thoroughly Gas Safe engineer
The engineer will check the entire flue run — including bends, joints, and the terminal — for blockages, incorrect fall, or damage. They will also verify that the flue length and configuration comply with installation requirements, as an oversized or undersized flue can affect gas flow and sensor readings.
- Gas Safe engineer: test the fan and combustion airflow Gas Safe engineer
The engineer will run the boiler under controlled conditions and measure fan speed and differential air pressure to confirm the fan is moving exhaust gases at the correct rate. A failing fan is replaced as a complete assembly.
- Gas Safe engineer: assess the PCB if all other components test as good Gas Safe engineer
If the thermistor, wiring, flue, and fan all check out correctly but E080 persists, the control board is the likely remaining cause. The engineer will arrange a PCB replacement. On older Vokèra boilers, the cost of a PCB should be weighed against the age and overall condition of the appliance before proceeding.
Parts you may need
- Flue thermistor (NTC sensor) · from £35
- Wiring harness / connector set · from £25
- Boiler fan / flue fan assembly · 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
Is E080 on my Vokèra boiler dangerous?
E080 is a safety lockout rather than an immediate emergency, but it should not be ignored. The code means the boiler cannot confirm that exhaust gases are being vented safely. Until the fault is resolved, leave the boiler off and do not repeatedly reset it. If you smell gas or suspect carbon monoxide, evacuate the property and call the National Gas Emergency Service on 0800 111 999 immediately.
Can I fix E080 myself, or do I need a Gas Safe engineer?
The only DIY steps are checking your gas supply, looking for an obvious flue terminal blockage from outside, and resetting the boiler once or twice. Everything else — testing the thermistor, inspecting internal wiring, examining the flue run, or replacing any components — must be carried out by a Gas Safe registered engineer. You can verify any engineer's credentials at GasSafeRegister.co.uk.
How much does it usually cost to fix E080 on a Vokèra boiler?
Most homeowners pay between £150 and £350 to resolve E080. A straightforward thermistor replacement — the most common repair — typically falls in the £120–£220 range including labour. Flue unblocking or inspection adds roughly £100–£200. If the PCB needs replacing the cost can rise to £400–£500 or more, which on an older Vokèra may make a new boiler the more economical option. Vokèra also offers a fixed-price repair scheme that covers call-out, labour, and parts up to a retail value of £450 inc. VAT, which can offer peace of mind on value.
Why does E080 keep coming back after I reset the boiler?
A recurring E080 almost always means the root cause — a failing thermistor, a loose connection, a partial flue blockage, or a struggling fan — is still present. The reset clears the boiler's memory of the lockout event, but the next heating cycle reproduces the same fault condition. Repeated resets without a repair do not fix anything and can delay identifying a deteriorating component, so book a Gas Safe engineer if the code returns after one or two resets.