Common problems guide

The most common Biasi M96E problems

The faults most likely to send a Biasi M96E 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
0 DIY-safe checks
6 engineer needed

The 6 most common faults

01
N/A High Engineer

Your boiler has automatically shut down because the water inside it has become dangerously hot, usually due to a blockage in the water flow.

Est. cost
£150-300
Parts
Circulator pump, Automatic bypass valve, Primary heat exchanger
Full guide for N/A
02
Faulty primary circuit High Engineer

Your boiler has detected that water isn't flowing properly through its internal heating pipes, so it has safely shut down to prevent damage.

Est. cost
£150-350
Parts
Circulating pump, Automatic bypass valve, Plate heat exchanger
Full guide for Faulty primary circuit
03
Faulty air pressure switch High Engineer

Your boiler has stopped working because it cannot safely confirm that exhaust gases are clearing properly.

Est. cost
£100-200
Parts
Air pressure switch, Pressure switch silicone tubes, Flue terminal
Full guide for Faulty air pressure switch
04
Lack of burner ignition High Engineer

Your boiler is failing to start up because it cannot get the flame to ignite.

Est. cost
£150-300
Parts
Ignition lead, Ignition electrode, Gas valve
Full guide for Lack of burner ignition
05
Safety thermostat lockout High Engineer

Your boiler has shut itself down safely because it detected that internal temperatures became too high.

Est. cost
£150-300
Parts
Safety thermostat, NTC thermistor, Automatic bypass valve
Full guide for Safety thermostat lockout
Parts most often replaced

on the Biasi M96E

Circulator pumpAutomatic bypass valvePrimary heat exchangerNTC thermistorCirculating pumpPlate heat exchanger

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 Biasi 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 Biasi M96E

Related guides

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