Vokera Sabre 35HE Fault codes & diagnostics

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

Combi Natural Gas 35 kW 2019-present
GC Number 47-094-72
Download the Vokera Sabre 35HE manual The official installation & service manual (PDF) — the exact document these fault codes were verified against. PDF

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 →

Just want the most common Vokera Sabre 35HE faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 4 documented codes

Tap any card for details

LED / flash-pattern codes
Red LED flashing every 0.5 seconds

Your boiler has shut down and locked itself out because it has detected a safety issue with the airflow, temperature sensors, or internal pressure.

High DIY-safe £100-280

What to check first

  1. Turn the mode selector dial to the 'OFF (0)' position.
  2. Wait for at least 2 minutes for the system to reset.
  3. Turn the dial back to the 'Hot Water/Heating' position and see if the light clears.

Parts commonly replaced

  • Fan
  • Limit Thermostat
  • Primary NTC Sensor
  • Air Pressure Switch

Related codes

Full explanation for Red LED flashing every 0.5 seconds
Digital codes
Green LED on every 0.5 seconds

Your boiler has paused because the water pressure is likely too low or it is struggling to clear air from the system.

High DIY-safe £100-220

What to check first

  1. Check the pressure gauge on the front of the boiler.
  2. If the needle is below 1 bar, use the filling loop valves underneath to top up the system to 1.5 bar.
  3. Ensure the black plastic taps are closed tight after filling and restart the boiler.

Parts commonly replaced

  • Air Pressure Switch
  • Expansion Vessel
  • Filling Loop Valve

Related codes

Full explanation for Green LED on every 0.5 seconds
Red LED solid

Your boiler has safety-locked itself because it has detected an issue with the sensors, fan, or internal water pressure.

High DIY-safe £90-280

What to check first

  1. Turn the mode selector dial to the 'OFF' (0) position.
  2. Wait for at least 2 minutes.
  3. Turn the dial back to your desired 'Heating' or 'Hot Water' setting to see if the system restarts.

Parts commonly replaced

  • Fan
  • Limit Thermostat
  • Primary NTC Temperature Sensor
  • Air Pressure Switch

Related codes

Full explanation for Red LED solid
Yellow LED solid

Your boiler has detected a sensor problem, so it is limiting your hot water to a constant temperature to prevent it from getting too hot.

Low Engineer only £90-160

Parts commonly replaced

  • DHW NTC Thermistor
  • Thermistor Clip

Related codes

Full explanation for Yellow LED solid
Status & diagnostic codes

2 operating states & engineer diagnostics

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

Green LED flashing rapidly (8/sec) Status Your boiler is currently in a normal pre-heat mode designed to provide hot water more quickly; this is a standard operating feature and not a fault. Green LED on every 6 seconds Status Your boiler is in standby mode and is working correctly with no detected faults.
Boiler cover options

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.