Vokera Vision Plus 35C/40C Fault codes & diagnostics

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

Combi Natural Gas 35-40 kW 2019-present

The Vision Plus 35C/40C range comes in 2 types

Pick the one you have. The fault codes, GC numbers and manual differ by type.

Each model has its own manual A family spans several manuals, one per model or generation. Pick your model above and its page has the manual its fault codes were read from.

The fault code is already on your display

Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →

Severity at a glance

Each cell = one fault code. Hover to identify.
3 Emergency 18 High 3 Medium

All 24 documented codes

Tap any card for details

<0,6 bar

Your boiler has lost the water pressure needed to circulate heat, so it has safely shut down to prevent damage.

High DIY-safe £80-150 Shared across the Vision Plus range

What to check first

  1. Locate the external filling loop, which is usually a silver braided hose under the boiler.
  2. Open the two valves on either end of the hose slowly to allow water into the system.
  3. Watch the pressure gauge until the needle reaches the green zone (ideally 1.0 to 1.5 bar).
  4. Close both valves tightly and remove the hose if required by your specific installation.

Parts commonly replaced

  • Pressure Relief Valve (PRV)
  • Expansion Vessel
  • Pressure Sensor
>3,0 bar

Your boiler's internal water pressure is too high, which can cause internal components to leak or the pressure relief valve to activate.

High DIY-safe £80-150 Shared across the Vision Plus range

What to check first

  1. Locate a radiator in your home that is easily accessible.
  2. Place a small container and a cloth under the radiator bleed valve.
  3. Open the bleed valve slowly to release air and a small amount of water until the pressure gauge on the boiler drops to between 1.0 and 1.5 bar.

Parts commonly replaced

  • Pressure relief valve
  • Filling loop
  • Pressure transducer
COM

Your boiler has lost the internal connection between its control units, causing it to stop operating completely for safety reasons.

High Engineer only £150-300 Shared across the Vision Plus range

Parts commonly replaced

  • PCB (Main control board)
  • Communication wiring harness
COM1

Your boiler has lost its connection to your room thermostat or central heating controller, meaning it doesn't know when to turn the heating on.

High Engineer only £120-250 Shared across the Vision Plus range

Parts commonly replaced

  • PCB
  • Communication cable
  • External thermostat/controller
COMP

Your boiler's electronic control system has lost the connection to its main internal heat controller, causing it to stop functioning correctly.

High Engineer only £150-300 Shared across the Vision Plus range

Parts commonly replaced

  • Main printed circuit board
  • Wiring harness
E010

Your boiler has stopped working because it cannot safely ignite or clear away waste gases, which may be caused by a blockage in the flue or drain pipes.

Emergency Engineer only £120-250 Shared across the Vision Plus range

Parts commonly replaced

  • Condensate trap
  • Ignition electrode
  • Flue seal
  • Gas valve
E011

Your boiler has detected that it cannot safely get rid of exhaust gases or is struggling to take in fresh air, so it has shut down to keep you safe.

Emergency Engineer only £120-250 Shared across the Vision Plus range

Parts commonly replaced

  • Flue assembly
  • Fan
  • Air pressure switch

Related codes

E020

Your boiler has detected a flame inside when it shouldn't be there, which has caused it to shut down for safety.

Emergency Engineer only £150-300 Shared across the Vision Plus range

Parts commonly replaced

  • Gas valve
  • Printed Circuit Board (PCB)
  • Flame detection electrode

Related codes

E030

Your boiler has detected that it is running too hot and has automatically shut itself down to prevent damage.

High Engineer only £120-250 Shared across the Vision Plus range

Parts commonly replaced

  • Limit thermostat
  • Pump
  • Diverter valve
  • Primary heat exchanger

Related codes

E040

Your boiler has detected that the internal part responsible for pushing out exhaust gases is not spinning correctly, so it has safely shut itself down to prevent any unsafe operation.

High Engineer only £180-300 Shared across the Vision Plus range

Parts commonly replaced

  • Fan assembly
  • Wiring harness
  • PCB

Related codes

Showing 11–20 of 24
E041

Your boiler has detected that the water pressure is too low or inconsistent to safely provide heating and hot water.

High Engineer only £120-220 Shared across the Vision Plus range

Parts commonly replaced

  • Flow switch
  • Pressure sensor
  • Water transducer

Related codes

E042

Your boiler is struggling to detect the flow of water because its internal sensor is faulty, which is preventing it from heating your water properly.

High Engineer only £150-250 Shared across the Vision Plus range

Parts commonly replaced

  • Water flow sensor/transducer
  • Wiring harness

Related codes

E060

Your boiler has lost the ability to accurately measure the temperature of the hot water it produces, so it has stopped heating your taps to prevent potential overheating.

High Engineer only £120-220 Shared across the Vision Plus range

Parts commonly replaced

  • Domestic Hot Water (DHW) NTC sensor
  • Wiring harness

Related codes

E070

Your boiler is having trouble measuring the temperature of the water used for your taps and shower, so it has stopped heating that water to prevent it from getting too hot.

Medium Engineer only £120-220 Shared across the Vision Plus range

Parts commonly replaced

  • Domestic Hot Water (DHW) NTC thermistor
  • Wiring harness

Related codes

E077

Your boiler is struggling to detect the flow of water through the system, which means it has stopped producing hot water and heating to prevent damage.

High Engineer only £150-250 Shared across the Vision Plus range

Parts commonly replaced

  • Flow sensor
  • Wiring harness

Related codes

E080

Your boiler has detected that the water inside the system is becoming dangerously hot, so it has safely shut itself down to prevent damage.

High Engineer only £150-250 Shared across the Vision Plus range

Parts commonly replaced

  • NTC thermistor
  • Primary heat exchanger
  • Pump

Related codes

E084

Your boiler has detected that the water temperature difference between the pipes entering and leaving the unit is not what it should be, causing it to shut down to prevent damage.

High Engineer only £150-250 Shared across the Vision Plus range

Parts commonly replaced

  • Flow/return sensors
  • Pump
  • Diverter valve

Related codes

E086

Your boiler has lost the ability to accurately measure the temperature of the water being sent to your radiators, causing it to stop running to prevent damage.

High Engineer only £150-250 Shared across the Vision Plus range

Parts commonly replaced

  • Flow temperature sensor
  • Wiring harness
E090

Your boiler has lost the ability to accurately measure the temperature of the water returning to it, so it has safely shut down to prevent overheating.

High Engineer only £120-200 Shared across the Vision Plus range

Parts commonly replaced

  • Return temperature sensor
  • Wiring harness

Related codes

E091

Your boiler has detected that the water returning to it from your radiators is getting too hot, so it has safely shut itself down to prevent damage.

High Engineer only £150-250 Shared across the Vision Plus range

Parts commonly replaced

  • Return temperature sensor
  • Pump
  • Primary heat exchanger

Related codes

Showing 21–24 of 24
E099

Your boiler has detected that the water is not circulating between the heating pipes as expected, causing the system to shut down to prevent overheating.

High Engineer only £150-300 Shared across the Vision Plus range

Parts commonly replaced

  • NTC Temperature Sensor
  • Circulation Pump
  • Primary Heat Exchanger

Related codes

FWER

Your boiler's computer software is not communicating correctly with the internal parts, causing the system to lock out for safety.

High Engineer only £150-250 Shared across the Vision Plus range

Parts commonly replaced

  • Main printed circuit board (PCB)
  • Control software upgrade module
OBCD

Your boiler's internal timer is malfunctioning, which means it cannot accurately track when your heating or hot water should turn on or off.

Medium Engineer only £150-250 Shared across the Vision Plus range

Parts commonly replaced

  • Digital timer clock
  • PCB
OTER

Your boiler is having a communication breakdown with its external thermostat or smart control system, meaning it doesn't know when to turn on or off.

Medium Engineer only £120-250 Shared across the Vision Plus range

Parts commonly replaced

  • OpenTherm interface module
  • PCB (Main control board)
  • External thermostat

Avoid the next call-out bill

Monthly cover means no unexpected bills when your boiler breaks down.

Approved partner
Domestic Appliance Guard
Unlimited call-outs, 24/7 helpline, no price-hike promise
Get a quote →

Affiliate links. We may earn a commission at no extra cost to you.