Baxi EcoBlue Heat Fault codes & diagnostics

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

Regular Natural Gas 12-30 kW 2014-2015 Discontinued
GC Numbers 41-470-0241-470-0341-470-0441-470-0541-470-06
Download the Baxi EcoBlue Heat manual The official installation & service manual (PDF) — the exact document these fault codes were verified against. PDF

This boiler uses LED flash patterns

Count the flashes in one repeating group before the pause. That number is your fault code. Do not reset until you have noted it. How to read fault codes →

Severity at a glance

Each cell = one fault code. Hover to identify.
12 High
Versions & GC numbers

Which version do you have?

The GC number on your boiler's data badge identifies the exact appliance and production years, as recorded in the UK Product Characteristics Database.

GC number Appliance (register name) Produced
41-470-02 EcoBlue Heat 12 2014–2015

Appliance names and production years are taken from the UK Product Characteristics Database (the SAP/SEDBUK register). Where a GC number is also printed in this model's own manufacturer manual, both sources were checked to agree.

Just want the most common Baxi EcoBlue Heat faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 12 documented codes

Tap any card for details

1 flash green

Your boiler has shut down because it is getting too hot too quickly, usually because the water inside isn't circulating properly.

High DIY-safe £100-£350

What to check first

  1. Check that your pump is running and hasn't seized
  2. Ensure all radiator valves are fully open to allow water to flow
  3. Check that the boiler pressure is between 1.0 and 1.5 bar
  4. Bleed all radiators to remove trapped air pockets

Parts commonly replaced

  • Circulation Pump
  • Flow/Return Thermistor
  • Heat Exchanger (De-scaling)

Related codes

Full explanation for 1 flash green
1 flash red

Your boiler has detected that water is either not moving through the system correctly or a temperature sensor has failed, preventing it from heating up safely.

High DIY-safe £75-180

What to check first

  1. Check that your central heating valves (under the boiler) are fully open
  2. Ensure all radiator valves are turned on to allow water to flow
  3. Reset the boiler by turning the selector switch to the 'R' position for five seconds

Parts commonly replaced

  • Flow temperature sensor (NTC)
  • Return temperature sensor (NTC)
  • Circulation pump

Related codes

Full explanation for 1 flash red
2 flashes green

Your boiler has shut down because a safety circuit or external control link has been disconnected or broken.

High Engineer only £90-180

Parts commonly replaced

  • User Interaction Controller
  • Wiring Harness
  • External Controls Link

Related codes

Full explanation for 2 flashes green
2 flashes red

Your boiler has got too hot and has shut itself down as a safety precaution.

High DIY-safe £120-350

What to check first

  1. Check that your radiator valves are open
  2. Ensure your system water pressure is between 1 and 1.5 bar
  3. Turn the selector switch to 'Reset' for five seconds and then back to 'On'

Parts commonly replaced

  • Over-temperature Thermostat
  • Circulation Pump
  • PCB

Related codes

Full explanation for 2 flashes red
3 flashes green

Your boiler was working but the flame has unexpectedly gone out, causing the system to stop for safety.

High DIY-safe £100-£280

What to check first

  1. Check if other gas appliances in your home, like a hob, are still working to ensure gas supply.
  2. Verify that your prepaid gas meter has credit if applicable.
  3. Restart the boiler by turning the selector switch to the reset position for five seconds.

Parts commonly replaced

  • Flame sensing electrode
  • Gas valve
  • Spark generator

Related codes

Full explanation for 3 flashes green
3 flashes red

Your boiler is failing to light the gas or cannot stay lit, which means your heating and hot water have stopped working.

High DIY-safe £100-350

What to check first

  1. Check if other gas appliances, like a cooker, are working to confirm gas supply is active
  2. Check that your credit meter has not run out of funds
  3. Press and hold the reset button for five seconds

Parts commonly replaced

  • Ignition Electrode
  • Flame Sensing Probe
  • Gas Valve
  • Printed Circuit Board (PCB)

Related codes

Full explanation for 3 flashes red
4 flashes green

Your boiler is having trouble sending messages between its internal electronic brains, meaning it cannot start the heating or hot water until the connection is restored.

High Engineer only £120-450

Parts commonly replaced

  • Wiring harness
  • Printed Circuit Board (PCB)
  • User interface/Display panel

Related codes

Full explanation for 4 flashes green
4 flashes red

Your boiler's fan, which safely clears exhaust gases, is either not spinning at the correct speed or has failed to start.

High Engineer only £220-450

Parts commonly replaced

  • Fan assembly
  • Printed Circuit Board (PCB)
  • Venturi tube

Related codes

Full explanation for 4 flashes red
5 flashes green

Your boiler's computer brain has become confused by its internal settings or has suffered a hardware failure, preventing it from starting up.

High Engineer only £180-450

Parts commonly replaced

  • Main PCB (Printed Circuit Board)
  • Parameter Key
Full explanation for 5 flashes green
5 flashes red

Your boiler's internal computer has lost communication with its main control board, meaning it cannot process the instructions needed to run properly.

High Engineer only £180-350

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Wiring Harness

Related codes

Full explanation for 5 flashes red
6 flashes green

Your boiler's electronic brain has encountered an internal error and is unable to manage the heating process safely.

High Engineer only £250-£450

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Combustion Control Unit

Related codes

Full explanation for 6 flashes green
6 flashes red

Your boiler has stopped working because its internal computer is struggling to talk to the connected parts or there is an error in its settings.

High Engineer only £120-450

Parts commonly replaced

  • Main PCB (Printed Circuit Board)
  • Wiring Harness
  • External Controls Interface

Related codes

Full explanation for 6 flashes red