Common problems guide

The most common Vokera Mynute HE problems

The faults most likely to send a Vokera Mynute HE 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.
16 documented codes
6 most common
2 DIY-safe checks
4 engineer needed

The 6 most common faults

01
AL40 High DIY-safe

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

What to try first

Locate the external or internal filling loop, which is a silver braided hose connecting two pipes beneath the boiler.Open the valves at both ends of the hose to allow mains water into the heating system.Watch the pressure gauge on the front of the boiler until the needle reaches the green zone, typically between 1 and 1.5 bar.Close both valves tightly and remove the hose if required by your specific model setup.

Est. cost
£0-£120
Parts
Filling loop, Pressure relief valve, Pressure sensor
Full guide for AL40
02
AL41 High DIY-safe

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

What to try first

Locate the external filling loop, which is usually a flexible silver braided hose connecting two pipes underneath the boiler.Open the small black or chrome valves at either end of the hose to allow mains water into the system.Monitor the boiler's pressure gauge until the needle reaches the green zone, typically between 1.0 and 1.5 bar.Close both valves tightly and ensure no water is leaking from the connection.

Est. cost
£0-£120
Parts
Filling loop, Pressure relief valve, Expansion vessel
Full guide for AL41
03
10 High Engineer

Your boiler has failed to ignite because it cannot detect a flame, meaning it currently cannot heat your home or water.

Est. cost
£120-250
Parts
Ignition electrode, Gas valve, PCB
Full guide for 10
04
AL10 High Engineer

Your boiler has failed to start because it cannot detect a flame or because your condensate drain pipe is blocked and backing up.

Est. cost
£120-250
Parts
Condensate trap, Ignition electrode, Gas valve
Full guide for AL10
05
AL20 High Engineer

Your boiler has detected that it is overheating and has safely shut itself down to prevent internal damage.

Est. cost
£120-250
Parts
Limit thermostat, Pump, Diverter valve
Full guide for AL20
06
AL21 High Engineer

Your boiler has detected an issue with an external control device, such as an external timer, thermostat, or heating programmer, which is preventing the system from operating correctly.

Est. cost
£120-250
Parts
External programmer, Room thermostat, Wiring harness
Full guide for AL21
Parts most often replaced

on the Vokera Mynute HE

Filling loopPressure relief valvePressure sensorExpansion vesselIgnition electrodeGas 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 16-code list for the Vokera Mynute HE

Related guides

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