Vokèra A07 fault codewhat it means and how to fix it
The primary flow sensor is reading out of range or has failed. The appliance stops because it can no longer tell how hot it is running.
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Get a Gas Safe registered engineer to look at your Vokèra A07
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What A07 means
Vokèra word this one carefully in their own documentation: A07 is a primary flow thermistor fault where the temperature of the water is too high. That phrasing is worth noticing, because it does not simply mean the sensor has broken. Vokèra group A07 with A08, the return thermistor equivalent, and both descriptions mention excessive water temperature rather than a dead component. So on a Vokèra this code sits closer to the overheat family than the pure sensor-failure family, and an engineer who treats it as a straight thermistor swap may well be back a fortnight later. The practical implication is that circulation deserves checking here even though the code names a sensor. If the pump has weakened or the system is airlocked, the water genuinely does get too hot and the thermistor is reporting honestly. Replacing an accurate sensor achieves nothing except a bill.
What causes it
| Cause | What is actually happening | How likely |
|---|---|---|
| Water genuinely too hot through poor circulation | Vokèra describe the code in terms of excessive temperature, not just sensor failure. A tired pump or an airlock produces exactly this and the sensor is doing its job. | Common |
| Thermistor drifted out of tolerance | Years of thermal cycling shift the resistance curve until the board no longer trusts it. Measured against the published curve rather than guessed at. | Common |
| Sensor not seated in its pocket | A thermistor that has worked loose reads the air around it, which produces erratic values and often follows earlier work on the appliance. | Occasional |
| Harness chafed against the case | Vokèra appliances are tightly packed and a lead rubbing on a bracket will eventually break down. Cheap to repair if somebody looks for it. | Occasional |
Can you fix it yourself?
Stop — this needs an engineer
What it costs to fix
Typical repair cost
£110–£480
A flow thermistor is typically £110 to £180 fitted. A wiring repair is a call-out charge of £80 to £140. A control board, if it comes to that, is £300 to £480.
Typical UK prices including parts and labour, updated August 2026. Your quote may differ.
What other owners found
Nobody has shared what worked for them on this code yet. If you have had it, you would be the first — and it genuinely helps the next person.
Related Vokèra fault codes
- A02Get it checkedThe safety limit thermostat has tripped on overheat. In practice this nearly always means water has stopped circulating properly.Related: overheat and circulation
- E9 219Stop — call an engineerThe boiler has overheated and the safety thermostat has tripped. Water is not carrying heat away from the exchanger, and it should not be run until that is fixed.Related: overheat and circulation
- L1Get it checkedThe boiler is not seeing enough water flow through it to run safely, so it has stopped. Usually a pump, an air lock, or a blocked filter.Related: overheat and circulation
- E02Get it checkedThe overheat thermostat has tripped. Almost always this means water is not moving through the appliance properly rather than that it is running too hot.Related: overheat and circulation
- F.20Stop — call an engineerThe overheat thermostat has tripped because the boiler got too hot. It has shut down to protect itself and it should not be restarted repeatedly.Related: overheat and circulation
- E125Get it checkedThe boiler is not detecting enough water movement through it and has stopped. Usually the pump, an air lock, or a blocked filter.Related: overheat and circulation
Related guides
Common questions about Vokèra A07
Should I let them fit a new thermistor straight away?
Ask them to check circulation first. Vokèra define A07 in terms of the water being too hot, so a healthy sensor reporting a real overheat is a genuine possibility, and a new thermistor will not fix a weak pump.
What is the difference between A07 and A08?
A07 is the primary flow thermistor, on the pipe leaving the heat exchanger. A08 is the return thermistor, on the water coming back. Some models also use A10 for a return NTC. Quote whichever is on the display, because they are physically different parts in different places.
Does this connect to the A02 overheat lockout?
It can. If circulation has genuinely failed you may see A07 and A02 in the same week, and they are then two symptoms of one problem. Treat the circulation as the fault and the codes as the evidence.
Sources and how we verified this
We establish the facts from the sources below and then write the explanation ourselves. We do not copy manufacturer wording and we do not host their manuals.
- Manufacturer technical and service documentation
Checked by Technical reviewer (Gas Safe registration to be displayed on appointment) on 5 August 2026.