Common problems guide

The most common Vokera Sabre 25 HE Plus problems

The faults most likely to send a Vokera Sabre 25 HE Plus into lockout — with plain-English causes, what to check first, estimated repair costs and whether you need a Gas Safe engineer.

5 documented codes
5 most common
1 DIY-safe checks
4 engineer needed

The 5 most common faults

01
DHW NTC fault High Engineer

Your boiler is struggling to accurately measure the temperature of your hot water, which usually results in the water not heating up at all.

Est. cost
£90-160
Parts
DHW NTC thermistor, Connecting wiring harness
Full guide for DHW NTC fault
02
RED LED ON every 0.5-secs High Engineer

Your boiler has detected a safety-related issue with its internal airflow or pressure, causing it to lock down for protection.

Est. cost
£120-280
Parts
Fan, Air Pressure Switch, Overheat Thermostat
Full guide for RED LED ON every 0.5-secs
03
RED LED Solid High Engineer

Your boiler has detected a faulty internal temperature sensor, causing it to shut down as a safety precaution.

Est. cost
£90-160
Parts
Primary NTC Thermistor, Wiring harness
Full guide for RED LED Solid
04
GREEN LED ON every 0.5-secs Medium DIY-safe

Your boiler has paused temporarily because it has detected a minor issue, most likely low water pressure or a brief interruption in the airflow.

What to try first

Check the pressure gauge on the front of the boiler; if it is below 1 bar, top it up to 1.5 bar using the filling loop.Restart the boiler by turning the mode selector switch to the 'OFF/RESET' position and then back to 'ON'.Check that the outdoor flue pipe is not obstructed by debris or snow.

Est. cost
£0-120
Parts
Air Pressure Switch, Pressure Sensor
Full guide for GREEN LED ON every 0.5-secs
05
YELLOW LED Solid Medium Engineer

Your boiler has detected a problem with the sensor that measures hot water temperature, which may prevent your taps from getting hot.

Est. cost
£90-160
Parts
DHW NTC Thermistor, Wiring harness
Full guide for YELLOW LED Solid
Parts most often replaced

on the Vokera Sabre 25 HE Plus

DHW NTC thermistorConnecting wiring harnessFanAir Pressure SwitchOverheat ThermostatCondensate Trap

Based on parts cited in our fault code database. Your engineer will confirm what's actually needed after diagnosis.

Call a Gas Safe engineer if…

  • You can smell gas or see signs of a leak
  • The Vokera shows an Emergency or High severity code
  • The boiler keeps locking out after repeated resets
  • You've tried the DIY checks and the fault hasn't cleared
  • There's visible water leaking from the boiler
  • The flame is yellow or orange instead of blue
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See the full 5-code list for the Vokera Sabre 25 HE Plus

Related guides

Boiler losing pressure → No hot water → When to replace → Symptom checker →