Common problems guide

The most common Vokera Compact 28 SE problems

The faults most likely to send a Vokera Compact 28 SE 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.
12 documented codes
6 most common
1 DIY-safe checks
5 engineer needed

The 6 most common faults

01
Alarm system water pressure High DIY-safe

Your boiler is currently unable to run because the water pressure inside the heating system has dropped too low.

What to try first

Ensure the central heating system is turned off and the boiler is cool.Locate the filling loop (a flexible silver hose) underneath the boiler.Open the valves on the filling loop to allow water to enter until the pressure gauge reads between 1.0 and 1.5 bar.Close both valves tightly and reset the boiler.

Est. cost
£80-150
Parts
Pressure relief valve, Filling loop, Expansion vessel
Full guide for Alarm system water pressure
02
Alarm high limit thermostat High Engineer

Your boiler has detected that it has become too hot and has automatically shut itself down to prevent damage.

Est. cost
£120-250
Parts
High limit thermostat, Pump, Diverter valve
Full guide for Alarm high limit thermostat
03
Fault sensors CH High Engineer

Your boiler's temperature sensor is providing an incorrect reading, which has caused the system to stop heating for your safety.

Est. cost
£120-200
Parts
Central Heating NTC Sensor
Full guide for Fault sensors CH
04
Flame lockout High Engineer

Your boiler has stopped working because it cannot light its internal flame or keep it burning.

Est. cost
£120-250
Parts
Ignition electrode, Gas valve, PCB (Printed Circuit Board)
Full guide for Flame lockout
05
NTC heating probe High Engineer

Your boiler has stopped working because a sensor that measures water temperature is providing an incorrect reading or has failed, causing the system to shut down for safety.

Est. cost
£120-200
Parts
NTC heating sensor, Wiring harness
Full guide for NTC heating probe
06
ACF electronic fault alarms High Engineer

Your boiler's internal control brain is unable to talk to the rest of the unit, meaning it has shut down for your safety and will not provide heating or hot water.

Est. cost
£200-450
Parts
Printed Circuit Board (PCB)
Full guide for ACF electronic fault alarms
Parts most often replaced

on the Vokera Compact 28 SE

Pressure relief valveFilling loopExpansion vesselHigh limit thermostatPumpDiverter valve

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 12-code list for the Vokera Compact 28 SE

Related guides

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