Vokera Option Fault codes & diagnostics

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

Combi Natural Gas 24-28 kW 2006-2009 Discontinued

Replaced by: Linea

This boiler uses LED flash patterns

Count the flashes in one repeating group before the pause. That number is your fault code. Do not reset until you have noted it. How to read fault codes →

Severity at a glance

Each cell = one fault code. Hover to identify.
1 Emergency 9 High 5 Low
Just want the most common Vokera Option faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 15 documented codes

Tap any card for details

LED / flash-pattern codes
GREEN LED BLINKS

Your boiler is working exactly as it should and is simply waiting for you to turn on a tap or adjust your heating.

Low DIY-safe

What to check first

  1. No action required as the light indicates the boiler is receiving power and functioning normally.
  2. If you have no heat, check that your room thermostat is turned up.
  3. Ensure the programmer or timer is set to an 'on' period.
Full explanation for GREEN LED BLINKS
RED LED BLINKS

Your boiler has detected a safety issue with its internal sensors or temperature controls and has shut itself down to prevent potential damage.

High DIY-safe £150-250

What to check first

  1. Check that your gas prepayment meter has credit
  2. Ensure other gas appliances in your home are working to confirm gas supply
  3. Press the Reset button or turn the dial to 'OFF/RESET' and back to 'ON'

Parts commonly replaced

  • NTC Temperature Sensor
  • High Limit Thermostat
  • Pressure Switch
Full explanation for RED LED BLINKS
Red LED Flashing

Your boiler has detected a safety issue and has shut down to protect your home, which means you currently have no heating or hot water until it is reset or repaired.

High DIY-safe £120-250

What to check first

  1. Locate the main control dial on the front of the boiler.
  2. Turn the dial to the 'OFF/RESET' position and wait for 5-10 seconds.
  3. Turn the dial back to the 'Hot Water' or 'Heating & Hot Water' position to restart the boiler.

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Printed Circuit Board (PCB)
  • Flame rectification probe
Full explanation for Red LED Flashing
Digital codes
All LEDs Off

Your boiler has lost all power and is completely unresponsive, meaning it is currently unable to provide heating or hot water.

High DIY-safe £120-250

What to check first

  1. Check if the main boiler power switch (fused spur) is turned on
  2. Check your home's main consumer unit to see if a circuit breaker has tripped
  3. Try replacing the 3-amp fuse in the boiler's external switch

Parts commonly replaced

  • PCB (Printed Circuit Board)
  • Fuses
  • Transformer
Full explanation for All LEDs Off
APPLIANCE FIRES THEN LOCKOUTS

Your boiler is struggling to keep its flame lit because it cannot get the right amount of gas or properly vent its waste gases, so it is shutting down for safety.

Emergency Engineer only £120-250

Parts commonly replaced

  • Gas valve
  • Flue seals
  • Venturi
Full explanation for APPLIANCE FIRES THEN LOCKOUTS
Green LED On, Yellow LED On

Your boiler has lost water pressure and needs to be topped up to function correctly again.

High DIY-safe £80-120

What to check first

  1. Locate the filling loop (a flexible metal hose) underneath the boiler that connects two pipes.
  2. Open the valves at both ends of the filling loop to allow water to enter the system.
  3. Watch the pressure gauge on the front of the boiler until it reaches the green zone (typically between 1.0 and 1.5 bar).
  4. Close both valves tightly and remove the filling loop if required by your specific model.

Parts commonly replaced

  • Filling loop
  • Pressure gauge
  • Expansion vessel
Full explanation for Green LED On, Yellow LED On
LD1

Your boiler has detected a lockout fault and has shut down to protect itself, meaning your heating and hot water will not work until it is reset.

High DIY-safe £100-300

What to check first

  1. Locate the mode selector switch on the front panel
  2. Turn the switch to the 'OFF/RESET' position
  3. Wait for 5-10 seconds
  4. Turn the switch back to either 'Hot Water Only' or 'Heating and Hot Water'

Parts commonly replaced

  • Ignition Electrode
  • Flame Sensing Probe
  • Printed Circuit Board (PCB)
Full explanation for LD1
LD2

Your boiler is operating normally and is currently in standby mode or waiting for a signal to provide heating or hot water.

Low DIY-safe

What to check first

  1. Check that your room thermostat is turned up high enough to call for heat
  2. Ensure your programmer or external timer is set to an 'On' period
  3. Verify that the boiler power switch is in the 'On' or 'Auto' position

Related codes

Full explanation for LD2
LD3

Your boiler is currently running a self-diagnostic test or is in a temporary programming mode indicated by a yellow flashing light.

Low DIY-safe £0-80

What to check first

  1. Wait 10-15 minutes for the light to stop flashing automatically
  2. Ensure the mode selector dial is set to 'Hot Water' or 'Heating and Hot Water' rather than the 'Reset' position
  3. Rotate the selector dial to 'Reset' for 5 seconds and then back to your desired setting

Parts commonly replaced

  • No parts usually required
  • Control knob/bezel

Related codes

Full explanation for LD3
Lockout

Your boiler has failed to light the flame, so it has safely shut itself down to prevent a build-up of unburnt gas.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • PCB
Full explanation for Lockout
RED LED LIGHT

Your boiler has stopped working because it failed to light the flame properly, or there is an internal communication error preventing it from running.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • PCB Control board
  • Gas valve
Full explanation for RED LED LIGHT
Red LED On

Your boiler has detected a general internal error and has safely shut itself down to prevent damage, meaning you currently have no heating or hot water.

High DIY-safe £120-250

What to check first

  1. Locate the mode selector switch on the front control panel.
  2. Turn the switch to the 'OFF/RESET' position and wait for 5 seconds.
  3. Turn the switch back to either the 'Hot Water' or 'Heating and Hot Water' position.

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Wiring harness
  • Ignition transformer

Related codes

Full explanation for Red LED On
YELLOW LED LIGHT

Your boiler is currently in a manual testing mode used by engineers during servicing, rather than being in its normal operating state.

Low DIY-safe £0-80

What to check first

  1. Locate the reset or mode selection dial/button on your control panel
  2. Switch the boiler off and back on again at the mains power supply
  3. Ensure the internal service toggle switch has not been accidentally bumped or left in the testing position
Full explanation for YELLOW LED LIGHT
Yellow LED On, Red LED On

Your boiler has stopped working because the water pressure inside the system is too low to operate safely.

High DIY-safe £0-120

What to check first

  1. Locate the filling loop, which is a silver braided flexible hose with one or sometimes two valves underneath the boiler.
  2. Open the valve(s) slowly to allow water into the system while watching the pressure gauge on the front panel.
  3. Close the valve(s) tightly once the needle reaches the green zone, typically between 1.0 and 1.5 bar.

Parts commonly replaced

  • Filling loop
  • Pressure relief valve
  • Pressure gauge

Related codes

Full explanation for Yellow LED On, Red LED On