Vokera Vibe MAX S Fault codes & diagnostics

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

System Natural Gas 2022-present
GC Numbers 41-364-1941-364-20
Download the Vokera Vibe MAX S manual The official installation & service manual (PDF) — the exact document these fault codes were verified against. PDF

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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.
1 Emergency 12 High 2 Medium 2 Low
Versions & GC numbers

Which version do you have?

The GC number on your boiler's data badge identifies the exact appliance and production years, as recorded in the UK Product Characteristics Database.

GC number Appliance (register name) Produced
41-364-19 VIBE MAX 20S 2022–present
41-364-20 VIBE MAX 25S 2022–present
Just want the most common Vokera Vibe MAX S faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 17 documented codes

Tap any card for details

>3.0 bar

Your boiler has too much water in the system, which puts extra stress on the internal components and may cause water to leak from the safety pipe.

Emergency DIY-safe £80-220

What to check first

  1. Check that the filling loop valves (under the boiler) are tightly closed.
  2. Locate a radiator and use a bleed key to release water into a jug until the pressure gauge drops to 1.5 bar.
  3. Monitor the pressure gauge to ensure it stays steady and does not climb back up.

Parts commonly replaced

  • Filling loop
  • Expansion vessel
  • Pressure relief valve

Related codes

Full explanation for >3.0 bar
A10

Your boiler has failed to ignite or stay lit, causing it to shut down as a safety precaution.

High DIY-safe £100-£350

What to check first

  1. Check that your gas prepayment meter has credit (if applicable).
  2. Ensure other gas appliances in your home, like a hob, are working correctly.
  3. Press the Reset button on the boiler control panel once to clear the fault.

Parts commonly replaced

  • Ignition Electrode
  • Gas Valve
  • Flame Sensing Probe
  • Spark Generator

Related codes

Full explanation for A10
A11

Liquid waste produced by your boiler cannot drain away, which has caused the system to shut down to prevent damage.

High DIY-safe £80-160

What to check first

  1. Locate the plastic pipe leading away from the boiler to a drain.
  2. If the pipe runs outside, check if it is frozen and pour warm (not boiling) water over the icy section.
  3. Check for any visible blockages or kinks in the external drainage pipe.
  4. Restart the boiler once the blockage is cleared.

Parts commonly replaced

  • Condensate trap
  • Internal discharge pipeworks

Related codes

Full explanation for A11
A20

Your boiler has detected that fumes are not being expelled correctly or air is not being taken in properly, causing it to shut down for safety.

High DIY-safe £100-280

What to check first

  1. Check the external flue pipe (white plastic pipe) for any outside obstructions like bird nests, leaves, or debris.
  2. Ensure the flue terminal is not covered by garden furniture, building materials, or foliage.
  3. If it is snowing, check that the flue terminal is not buried or blocked by ice buildup.

Parts commonly replaced

  • Flue Fan
  • Air Pressure Switch
  • Flue Seals

Related codes

Full explanation for A20
A30

Your boiler has detected a flame when there shouldn't be one, which is causing the system to shut down for safety.

High Engineer only £120-350

Parts commonly replaced

  • Flame sense electrode
  • Gas valve
  • Main PCB

Related codes

Full explanation for A30
A40

Your boiler has shut down because it has reached an unsafe temperature and needs to cool down before it can be reset.

High DIY-safe £100-250

What to check first

  1. Check that all radiator valves are fully open to allow water to circulate.
  2. Ensure there is enough water pressure in the system (typically 1.0 to 1.5 bar).
  3. Press the reset button or turn the mode selector to 'off/reset' and then back to 'on' once the boiler has cooled.

Parts commonly replaced

  • Overheat Thermostat
  • Circulation Pump
  • Main Heat Exchanger

Related codes

Full explanation for A40
A41

Your boiler has detected that the water pressure is getting too low to operate correctly and needs to be topped up.

Medium DIY-safe £0-120

What to check first

  1. Locate the filling loop (usually a silver braided hose with small valves) underneath the boiler.
  2. Slowly open the valves until you hear water flowing into the unit.
  3. Watch the pressure gauge and close the valves tightly once it reaches 1.5 bar.

Parts commonly replaced

  • Filling loop
  • Pressure sensor
  • Expansion vessel

Related codes

Full explanation for A41
A42

Your boiler has detected that the water pressure is getting too low and needs to be topped up to continue working properly.

Low DIY-safe £0-80

What to check first

  1. Locate the filling loop valves underneath the boiler.
  2. Slowly open both valves to allow water into the system.
  3. Monitor the pressure gauge until it reaches between 1.0 and 1.5 bar, then close both valves tightly.

Parts commonly replaced

  • External filling loop
  • Pressure sensor

Related codes

Full explanation for A42
A58

Your boiler has stopped working because the electricity supply reaching it is too low to run its internal components safely.

High Engineer only £120-350

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • External Power Supply Cable

Related codes

Full explanation for A58
A59

Your boiler has detected an electrical surge or an unusually high voltage coming from the mains power supply, causing it to shut down for safety.

High Engineer only £120-350

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Surge Protector

Related codes

Full explanation for A59
A60

Your boiler has lost the ability to monitor its own internal water pressure correctly, preventing it from running safely.

High Engineer only £140-£260

Parts commonly replaced

  • Pressure transducer
  • Wiring harness
  • Main PCB

Related codes

Full explanation for A60
A70

Your boiler has detected an internal communication error or a sensor issue, preventing it from heating your water correctly.

High Engineer only £120-280

Parts commonly replaced

  • Flow temperature sensor
  • PCB (Printed Circuit Board)
  • Wiring harness

Related codes

Full explanation for A70
A80

Your boiler has detected an issue with the temperature of the water returning to the unit, suggesting a sensor failure or a lack of proper water circulation.

High Engineer only £90-180

Parts commonly replaced

  • Return NTC thermistor
  • Flow/Return sensor wiring loom
  • Circulation pump

Related codes

Full explanation for A80
A90

Your boiler has detected a problem with the sensor that monitors exhaust gases, which has caused the system to shut down for safety.

High Engineer only £140-£220

Parts commonly replaced

  • Flue gas NTC sensor
  • Wiring harness
  • Main PCB

Related codes

Full explanation for A90
A91

Your boiler has detected that the main heating component is becoming blocked with debris or limescale, which is preventing it from heating properly.

Medium Engineer only £120-250

Parts commonly replaced

  • Primary Heat Exchanger
  • Heating System Filter

Related codes

Full explanation for A91
FIL

Your boiler has detected that the water pressure is too low, meaning there is not enough water in the system to operate safely.

High DIY-safe £0-120

What to check first

  1. Locate the filling loop (the flexible silver hose) underneath or near the boiler.
  2. Slowly open the one or two taps on the loop until you hear water flowing.
  3. Watch the pressure gauge and close the taps firmly once it reaches between 1.0 and 1.5 bar.

Parts commonly replaced

  • Filling loop valve
  • Pressure sensor
  • Expansion vessel recharge

Related codes

Full explanation for FIL
SFS

Your boiler is not broken, but it has reached its pre-set service interval and requires a routine maintenance check by a professional to ensure it stays in good working order.

Low Engineer only £80-£120

Parts commonly replaced

  • Service kit (o-rings and seals)
  • Electrode (if worn)

Related codes

Full explanation for SFS
Status & diagnostic codes

1 operating states & engineer diagnostics

Not faults — these are normal operating states. Tap to expand.

CFS Diagnostic Your boiler has detected an internal fault that requires a professional inspection to prevent the system from locking out completely.
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