Common problems guide

The most common Vokera Maxim problems

The faults most likely to send a Vokera Maxim 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.
6 documented codes
6 most common
3 DIY-safe checks
3 engineer needed

The 6 most common faults

01
Alarm system water pressure High DIY-safe

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

What to try first

Locate the filling loop (a flexible metal hose) underneath your boiler.Open the valves on the hose to let mains water into the system until the pressure gauge reads between 1 and 1.5 bar.Close the valves tightly and press the reset button on your boiler.

Est. cost
£80-120
Parts
Pressure relief valve, Expansion vessel, Filling loop
Full guide for Alarm system water pressure
02
low-pressure fault code High DIY-safe

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

What to try first

Locate the external filling loop, which is a silver braided hose connected between two valves underneath your boiler.Slowly open both valves on the filling loop to allow cold mains water to enter the system.Watch the pressure gauge on the front of the boiler until the needle reaches the green zone, ideally around 1.0 to 1.5 bar, then securely close both valves.

Est. cost
£80-120
Parts
Filling loop, Pressure relief valve, Pressure transducer
Full guide for low-pressure fault code
03
Alarm high limit thermostat High Engineer

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

Est. cost
£120-250
Parts
High limit thermostat, Pump, Diverter valve
Full guide for Alarm high limit thermostat
04
Fault sensors High Engineer

Your boiler has detected that one of its internal temperature sensors is providing unreliable information, so it has shut down to prevent overheating.

Est. cost
£120-220
Parts
NTC thermistor, Wiring harness
Full guide for Fault sensors
05
Red led fixed High Engineer

Your boiler has stopped working because it cannot safely ignite or prove a flame, meaning you currently have no heating or hot water.

Est. cost
£120-250
Parts
Ignition electrode, Printed Circuit Board (PCB), Gas valve
Full guide for Red led fixed
06
Temporary fault Low DIY-safe

Your boiler is experiencing a minor, fleeting glitch that has caused it to pause operation briefly.

What to try first

Locate the reset button on the front control panelPress and hold the reset button for 5 secondsWait up to 5 minutes to see if the burner ignites and the fault clears

Full guide for Temporary fault
Parts most often replaced

on the Vokera Maxim

Pressure relief valveExpansion vesselFilling loopPressure transducerHigh limit thermostatPump

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 6-code list for the Vokera Maxim

Related guides

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