Common problems guide

The most common Vokera Sabre 29HE problems

The faults most likely to send a Vokera Sabre 29HE into lockout — with plain-English causes, what to check first, estimated repair costs and whether you need a Gas Safe engineer.

This model is discontinued. Parts can be harder to source and expensive. If repair costs are mounting, a new A-rated boiler may be the smarter choice.
9 documented codes
6 most common
1 DIY-safe checks
5 engineer needed

The 6 most common faults

01
ON every 0.5-secs (Red LED) High Engineer

Your boiler has detected a critical internal safety fault and has locked itself down to prevent damage, meaning it will not provide any heating or hot water until a professional engineer repairs it.

Est. cost
£120-300
Parts
Pressure switch, Fan assembly, Limit thermostat
Full guide for ON every 0.5-secs (Red LED)
02
Solid (Red LED) High Engineer

Your boiler has stopped working because it can no longer accurately read the temperature of the water inside the heating system.

Est. cost
£120-220
Parts
Primary NTC sensor, Wiring harness
Full guide for Solid (Red LED)
03
DHW NTC fault Medium Engineer

Your boiler is struggling to accurately detect the temperature of the water being heated for your taps, which means it may fail to provide hot water or heat it to the wrong temperature.

Est. cost
£120-200
Parts
Domestic Hot Water (DHW) NTC Thermistor
Full guide for DHW NTC fault
04
ON every 0.5-secs (Green LED) Low DIY-safe

Your boiler is pausing temporarily due to a minor safety check, such as a drop in system water pressure or a momentary blocked air signal.

What to try first

Check the pressure gauge on the front of your boiler to ensure it is sitting between 1 and 1.5 bar.If the pressure is below 1 bar, use the filling loop underneath the boiler to top it back up.Turn the boiler off and on again at the mains switch to reset the temporary fault.

Parts
Air Pressure Switch, Pressure Relief Valve, Filling Loop
Full guide for ON every 0.5-secs (Green LED)
05
Solid (Yellow LED) Medium Engineer

Your boiler is struggling to accurately measure the temperature of your hot water, which means it may fail to provide hot water or heat it to the wrong temperature.

Est. cost
£120-200
Parts
DHW NTC thermistor, Wiring harness
Full guide for Solid (Yellow LED)
06
Flashing 8-times a second Low Engineer

Your boiler is currently protecting itself by performing a self-check on the water temperature sensors to ensure it is heating safely.

Est. cost
£100-200
Parts
NTC Sensor, PCB
Full guide for Flashing 8-times a second
Parts most often replaced

on the Vokera Sabre 29HE

Pressure switchFan assemblyLimit thermostatPCBPrimary NTC sensorWiring harness

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
See the full 9-code list for the Vokera Sabre 29HE

Related guides

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