Baxi EcoBlue System Fault codes & diagnostics

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

System Natural Gas 12-32 kW 2015 onwards Discontinued
GC Numbers 41-070-2341-070-2441-070-2541-070-2641-070-2741-470-28

Replaced by: Baxi 600 System

Download the Baxi EcoBlue System manualThe official installation and service manual (PDF). PDF
Other editions of this manual (the one above is 7219708 - 03 (03/17)): 7219708 - 01 (04/15) (PDF) Manufacturers revise a model over the years. If your boiler is older than the manual above, an earlier edition may match it better.

The fault code is already on your display

Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →

Severity at a glance

Each cell = one fault code. Hover to identify.
2 Emergency 23 High 1 Medium

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
41-470-28 Ecoblue 32 System ErP 2015–present

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.

All 26 documented codes

Tap any card for details

08

Your boiler's electronic brain is experiencing an internal communication error that is preventing it from operating correctly.

High Engineer only £150-300

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Wiring harness
20

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

High Engineer only £120-200

Parts commonly replaced

  • Central Heating NTC sensor
  • Wiring harness

Related codes

28

Your boiler has detected a faulty sensor that monitors the temperature of the exhaust fumes, causing it to shut down for safety reasons.

High Engineer only £150-250

Parts commonly replaced

  • Flue NTC sensor
  • Wiring harness

Related codes

40

Your boiler is struggling to accurately measure the temperature of the water returning to it, so it has stopped operating to stay on the safe side.

High Engineer only £120-200

Parts commonly replaced

  • Return NTC thermistor sensor
  • Wiring harness

Related codes

109

Your boiler is struggling to pump water around your heating system effectively, so it has stopped working to prevent itself from overheating.

High Engineer only £150-350

Parts commonly replaced

  • Central heating pump
  • System filter
  • Diverter valve

Related codes

109 R

Your boiler is struggling to pump water around your heating system effectively, so it has shut down to protect itself from overheating.

High Engineer only £150-300

Parts commonly replaced

  • Circulation Pump
  • System Filter
  • Diverter Valve

Related codes

110

Your boiler has detected that it is overheating and has shut itself down to prevent damage because it cannot circulate water properly.

High DIY-safe £180-350

What to check first

  1. Turn off the boiler and allow it to cool down completely.
  2. Use a radiator key to bleed all radiators to remove any trapped air.
  3. Check the boiler pressure gauge and top it up to 1.5 bar if it has dropped.
  4. Turn the boiler back on and press the 'Reset' button.

Parts commonly replaced

  • Central heating pump
  • Safety thermostat
  • PCB
110 R

Your boiler has detected that it is overheating and has shut itself down to prevent damage, likely because the water inside isn't circulating properly.

High Engineer only £150-300

Parts commonly replaced

  • Circulating pump
  • Safety overheat thermostat
  • Central heating sensor

Related codes

111

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

High Engineer only £120-250

Parts commonly replaced

  • Safety Thermostat
  • System Pump
  • Diverter Valve
  • Heat Exchanger

Related codes

111 R

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

High Engineer only £150-300

Parts commonly replaced

  • Pump
  • Diverter valve
  • Heat exchanger
  • Safety thermostat
Showing 11–20 of 26
117

Your boiler's water pressure is currently too high, which has caused it to stop working as a safety precaution.

Medium DIY-safe £80-120

What to check first

  1. Locate a radiator in your home, preferably one upstairs.
  2. Place a cloth or small container under the radiator bleed valve.
  3. Use a radiator bleed key to slowly release a small amount of water until the pressure gauge on the front of your boiler drops into the green zone (usually between 1 and 1.5 bar).
  4. Once the pressure is correct, tighten the bleed valve securely.

Parts commonly replaced

  • Pressure relief valve
  • Expansion vessel
  • Filling loop valve

Related codes

118

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

High DIY-safe £80-150

What to check first

  1. Locate the external filling loop, which is a small silver flexible hose connecting two pipes near the boiler.
  2. Open the valves at both ends of the hose to allow water into the system until the pressure gauge reads between 1.0 and 1.5 bar.
  3. Close both valves tightly and ensure the hose is disconnected if required by your specific setup.

Parts commonly replaced

  • Filling loop
  • Pressure relief valve
  • Pressure sensor

Related codes

125

Your boiler has detected that hot water is not flowing around your heating system correctly, which is causing it to shut down to prevent overheating.

High DIY-safe £150-350

What to check first

  1. Check that your system pressure is between 1 and 1.5 bar on the pressure gauge
  2. Ensure all radiator valves and isolation valves under the boiler are fully open
  3. Bleed your radiators to remove any trapped air pockets

Parts commonly replaced

  • Central heating pump
  • Diverter valve
  • System filter
125 R

Your boiler has detected that hot water is not circulating properly around your heating system, so it has turned itself off to prevent overheating.

High Engineer only £150-350

Parts commonly replaced

  • Central heating pump
  • Diverter valve
  • Filter/System blockage
128

Your boiler has attempted to start but failed to detect a flame, causing it to stop operating to ensure your safety.

High DIY-safe £120-250

What to check first

  1. Check that your gas pre-pay meter has credit
  2. Ensure other gas appliances in your home are working to confirm gas supply
  3. Press the 'Reset' button for five seconds

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Printed Circuit Board (PCB)
130

Your boiler has detected that the temperature in the exhaust flue is too high, causing it to shut down for safety reasons.

Emergency Engineer only £150-300

Parts commonly replaced

  • Flue sensor
  • NTC thermistor
  • PCB
133

Your boiler has attempted to start but could not light the internal flame, so it has shut down to prevent gas from building up.

High DIY-safe £120-250

What to check first

  1. Check that your gas supply is turned on and you have credit on your meter.
  2. During freezing weather, check if your external white plastic condensate pipe is frozen and thaw it with warm water.
  3. Press the Reset button for five seconds.

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Printed Circuit Board
133 R

Your boiler has stopped working because it cannot light the flame required to produce heat or hot water.

High Engineer only £120-£250

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Circuit board (PCB)
  • Flame rectification probe
151

Your boiler is trying to start but the flame won't stay lit, meaning your heating and hot water will not work.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Flame rectification probe
151 R

Your boiler has attempted to ignite several times but has failed to detect a flame, causing it to shut down for safety.

High Engineer only £120-250

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Printed circuit board
Showing 21–26 of 26
160

Your boiler's air circulation system has stopped working properly, preventing it from igniting safely.

High Engineer only £250-450

Parts commonly replaced

  • Fan assembly
  • Wiring harness
  • Control PCB
160 R

Your boiler has detected that the internal fan responsible for safely venting exhaust gases is not working correctly, causing it to shut down for safety reasons.

High Engineer only £250-450

Parts commonly replaced

  • Fan assembly
  • Printed Circuit Board (PCB)
  • Wiring harness
162

Your boiler has detected an issue with how it clears exhaust gases or brings in fresh air, preventing it from firing up for safety.

High Engineer only £120-£250

Parts commonly replaced

  • Air Pressure Switch
  • Venturi tube
  • Fan
321

Your boiler has identified a problem with the temperature sensor, which is preventing it from safely heating your water.

High Engineer only £120-220

Parts commonly replaced

  • NTC Temperature Sensor
  • Wiring harness
384

Your boiler has detected what it thinks is a flame inside the unit when the gas is supposed to be turned off, so it has shut down for safety.

Emergency Engineer only £150-300

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Flame sensing electrode
E118

Your boiler has stopped working because the water pressure inside the heating system has dropped below the required level.

High DIY-safe £80-120

What to check first

  1. Locate the filling loop (usually a silver braided hose with one or two valves) connected to the boiler pipework.
  2. Gradually open the valve(s) to allow cold mains water to enter the system until the pressure gauge on the front of the boiler reads between 1.0 and 1.5 bar.
  3. Carefully close the valve(s) tightly to ensure no further water enters and the boiler restarts automatically.

Parts commonly replaced

  • Pressure relief valve
  • Expansion vessel
  • Filling loop

17 operating states & engineer diagnostics

Not faults — these are normal operating states. Tap to expand.

01 Status Your boiler has detected that the water inside the heating system has become dangerously hot or is failing to move around the pipes properly. 02 Diagnostic Your boiler is having trouble communicating with the outdoor sensor that measures the air temperature, which may affect how efficiently your heating responds to weather changes. 03 Diagnostic Your boiler is struggling to detect the temperature of your hot water cylinder, preventing it from heating your water correctly. 04 Diagnostic Your boiler has detected an issue with the sensor that tracks the temperature of your water, which usually prevents the system from heating it correctly. 05 Diagnostic Your boiler has detected that the water pressure level inside the heating system has dropped too low for it to operate safely. 06 Diagnostic Your boiler has detected that the water returning from your radiators is at an unexpected temperature, causing it to pause for safety. 07 Diagnostic Your boiler has detected that the exhaust gases leaving the flue are hotter than they should be, so it has shut down to protect the system. 09 Diagnostic Your boiler has detected an issue with the temperature sensor reading, meaning it cannot safely monitor how hot the water inside is and has shut down to prevent damage. 10 Diagnostic Your boiler is unable to detect or properly control the temperature of the water circulating through your heating system. 12 Diagnostic Your boiler has failed to ignite because it cannot detect the flame, meaning it has safely shut itself down to prevent a gas buildup. 13 Diagnostic Your boiler is simply displaying a notification to let you know it has reached a certain number of hours of operation. 14 Diagnostic Your boiler is signalling an issue with the heating control system, which may be preventing your radiators from warming up as expected. 15 Diagnostic Your boiler is struggling to communicate with a secondary heating zone, such as an upstairs thermostat or a separate floor circuit. 16 Diagnostic Your boiler is signalling an issue while attempting to provide domestic hot water, likely due to a sensor or flow detection problem. 17 Diagnostic Your boiler is currently running normally and is successfully carrying out your heating or hot water request. 18 Diagnostic Your boiler is currently set to communicate with a solar water heating system, which is not a standard fault. 19 Diagnostic Your boiler has identified an internal electronic communication error that prevents it from starting up correctly.