Vokera Vision Plus 20 S Fault codes & diagnostics

23 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.

GC Number 41-364-06
Download the Vokera Vision Plus 20 S manualThe official installation and service manual (PDF), the document these fault codes were read from. PDF

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Severity at a glance

Each cell = one fault code. Hover to identify.
2 Emergency 17 High 3 Medium 1 Low

All 23 documented codes

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>3,0 bar

Your boiler's internal water pressure is currently too high, which can put unnecessary strain on the system's components.

High DIY-safe £80-150

What to check first

  1. Locate a radiator in your home, preferably one upstairs or near the boiler.
  2. Using a radiator bleed key, slightly open the bleed valve to release a small amount of water into a container.
  3. Monitor the pressure gauge on the front of the boiler until the needle drops back into the green zone, usually between 1.0 and 1.5 bar.

Parts commonly replaced

  • Pressure Relief Valve (PRV)
  • Expansion Vessel
  • Pressure Gauge

Related codes

COM

Your boiler's internal computer is having trouble talking to the control panel, meaning the unit cannot receive instructions to provide heating or hot water.

High Engineer only £150-300

Parts commonly replaced

  • Interface cable
  • PCB (Printed Circuit Board)
  • User interface display
COM1

Your boiler has lost its connection to the external wall-mounted heating controller, meaning it no longer knows when to turn your heating on or off.

Medium Engineer only £120-250

Parts commonly replaced

  • Communication PCB
  • Room thermostat
  • Wiring harness
COMP

Your boiler has lost the digital connection between its main brain and the operating controls, causing it to stop functioning correctly.

High Engineer only £150-£300

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Wiring loom
  • External controls interface

Related codes

E010

Your boiler has stopped working because it cannot safely detect a flame or the pipe that drains wastewater is blocked or frozen.

High DIY-safe £90-200

What to check first

  1. Check if your external condensate pipe (the white plastic pipe outside) is frozen during cold weather and pour warm water over it to thaw.
  2. Check if your gas supply is working properly by testing another gas appliance like a hob.
  3. Try resetting the boiler using the reset button on the control panel.

Parts commonly replaced

  • Condensate trap
  • Ignition electrode
  • Gas valve

Related codes

E011

Your boiler has detected a potential issue with the exhaust gases leaving the flue or the air it uses to burn gas safely.

Emergency Engineer only £100-250

Parts commonly replaced

  • Air pressure switch
  • Flue terminal
  • Fan
  • Printed circuit board

Related codes

E020

Your boiler has shut down because it has reached an unsafe temperature, triggered by a safety sensor that prevents the unit from overheating.

High DIY-safe £120-280

What to check first

  1. Check that all radiator valves are fully open to allow water to circulate.
  2. Ensure your system pressure is topped up to between 1 and 1.5 bar.
  3. Turn the boiler off and on again, or press the 'Reset' button to clear the lockout once the system has cooled down.

Parts commonly replaced

  • Limit thermostat (Overheat sensor)
  • Circulation pump
  • Main Heat Exchanger (Flushing)
E030

Your boiler has stopped working because the fan that removes waste gases is not spinning or communicating correctly with the system.

High Engineer only £250-£450

Parts commonly replaced

  • Fan assembly
  • Printed Circuit Board (PCB)
  • Wiring harness
E040

Your boiler is struggling to accurately measure how much water pressure is inside the system, which is preventing it from firing up correctly.

High Engineer only £150-250

Parts commonly replaced

  • Pressure transducer
  • Wiring harness

Related codes

E041

Your boiler is struggling to detect enough water pressure to operate safely and has shut down to prevent damage.

High Engineer only £120-220

Parts commonly replaced

  • Water pressure sensor
  • Pressure transducer

Related codes

Showing 11–20 of 23
E042

Your boiler has lost the ability to measure the water pressure accurately, which has caused it to stop running for safety.

High Engineer only £130-210

Parts commonly replaced

  • Water Pressure Transducer
  • Wiring Harness

Related codes

E060

Your boiler's internal computer has lost its specific 'identity' settings, meaning it has forgotten how to operate as your specific model.

High Engineer only £120-250

Parts commonly replaced

  • Main PCB
E070

Your boiler is temporarily unable to accurately measure the flow of water inside the system due to a faulty sensor.

Medium Engineer only £120-250

Parts commonly replaced

  • Flow sensor
  • Flow meter harness

Related codes

E077

Your boiler has detected that the water temperature inside is rising too fast or there is a major temperature difference between the pipes, so it has safely shut down to prevent overheating.

High Engineer only £150-300

Parts commonly replaced

  • Flow/Return temperature sensor
  • Water flow sensor
  • Circulating pump

Related codes

E080

Your boiler has detected that the water temperature coming back from your radiators is too different from the temperature leaving the boiler, which has caused it to shut down to prevent damage.

High Engineer only £120-220

Parts commonly replaced

  • Return NTC thermistor
  • Flow NTC thermistor
  • Wiring harness
E084

Your boiler has lost the ability to accurately measure the water temperature in your heating pipes, which prevents it from running your central heating safely.

High Engineer only £150-250

Parts commonly replaced

  • Delivery NTC probe
  • Wiring harness
E086

Your boiler has lost its connection to the sensor that monitors the temperature of the water being sent to your radiators, causing the system to stop heating for safety.

High Engineer only £120-220

Parts commonly replaced

  • Temperature sensor (NTC probe)
  • Wiring harness

Related codes

E090

Your boiler has detected that the temperature in the exhaust system is too high, causing it to shut down for safety reasons.

Emergency Engineer only £120-220

Parts commonly replaced

  • Flue gas sensor
  • PCB

Related codes

E091

Your boiler has detected that the main part responsible for heating your water is becoming blocked or dirty and needs a professional service.

Medium Engineer only £100-250

Parts commonly replaced

  • Heat exchanger cleaning fluid
  • Heat exchanger seals
  • Primary heat exchanger

Related codes

E099

Your boiler has stopped working because it has failed to start too many times in a row, meaning it has now locked itself out for safety.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • PCB

Related codes

Showing 21–23 of 23
FWER

Your boiler's internal computer is experiencing a software mismatch, meaning the control board does not recognise the installed firmware version.

High Engineer only £150-300

Parts commonly replaced

  • PCB Control Board
OBCD

The internal clock that schedules your heating and hot water has developed a fault, meaning the boiler cannot keep track of time or follow your programmed settings.

Low Engineer only £120-200

Parts commonly replaced

  • Time clock module
  • PCB interface board
OTER

Your boiler is struggling to communicate correctly with your thermostat or external controls, so it has stopped heating to prevent errors.

High Engineer only £120-250

Parts commonly replaced

  • OpenTherm module
  • PCB
  • External thermostat/controller

Related codes

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