Baxi Megaflo 2 System 18 COMPACT GA Fault codes & diagnostics

9 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.

System Natural Gas 2011-2015 Discontinued
GC Number 41-075-72
No manual available yet We don't hold the official service manual for this model yet. We're sourcing it.

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Severity at a glance

Each cell = one fault code. Hover to identify.
1 Emergency 8 High

All 9 documented codes

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E20

Your boiler has lost the ability to accurately measure the temperature of the central heating water, so it has shut down to prevent overheating.

High Engineer only £120-220 Shared across the Megaflo range

Parts commonly replaced

  • Central Heating (CH) NTC Sensor
  • Wiring Harness

Related codes

E28

Your boiler has detected an issue with its internal airflow or exhaust system, causing it to shut down for safety reasons.

Emergency Engineer only £150-300 Shared across the Megaflo range

Parts commonly replaced

  • Air Pressure Switch
  • Flue NTC Sensor
  • Fan Assembly
  • Condensate Trap

Related codes

E110

Your boiler has detected that it is overheating and has automatically switched itself off to prevent damage.

High Engineer only £120-250 Shared across the Megaflo range

Parts commonly replaced

  • Pump
  • Diverter Valve
  • Primary Thermistor
  • Heat Exchanger

Related codes

E119

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

High DIY-safe £80-150 Shared across the Megaflo range

What to check first

  1. Locate the filling loop (usually a silver braided hose with a valve) underneath the boiler.
  2. Open the valve(s) to allow mains water into the boiler.
  3. Monitor the pressure gauge on the front of the unit until it reaches between 1.0 and 1.5 bar, then securely close the valve.

Parts commonly replaced

  • Pressure relief valve
  • Pressure sensor
E125

Your boiler is struggling to pump water around your heating system correctly, which is preventing it from heating your home or water safely.

High Engineer only £150-350 Shared across the Megaflo range

Parts commonly replaced

  • Central heating pump
  • Diverter valve
  • System filter

Related codes

E130

Your boiler has detected that the temperature of the exhaust gases leaving the flue is too high, causing it to shut down to prevent overheating.

High Engineer only £150-300 Shared across the Megaflo range

Parts commonly replaced

  • Flue NTC sensor
  • Wiring harness
  • Primary heat exchanger

Related codes

E133

Your boiler has stopped working because it cannot light its internal flame, which is likely due to an issue with the gas supply or the ignition process.

High Engineer only £120-250 Shared across the Megaflo range

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Printed Circuit Board (PCB)

Related codes

E160

Your boiler has detected an issue with the internal ventilation system that prevents it from starting up safely.

High Engineer only £180-350 Shared across the Megaflo range

Parts commonly replaced

  • Fan assembly
  • Wiring harness
  • Printed Circuit Board (PCB)

Related codes

E193

Your boiler is struggling to get water moving through the system properly before it attempts to fire up.

High Engineer only £150-350 Shared across the Megaflo range

Parts commonly replaced

  • Central heating pump
  • Pressure sensor
  • Flow switch

Related codes