ECA Confeo Premix HST Fault codes & diagnostics

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

System Natural Gas 2020-present
GC Numbers 41-814-3541-814-3641-814-3741-814-3841-814-3941-814-40
Download the ECA Confeo Premix HST manual The official installation & service manual (PDF) — the exact document these fault codes were verified against. PDF

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.
1 Emergency 34 High 1 Medium 2 Low
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
41-814-37 Confeo Premix P 24 HST NG ERP YBK UK 2020–present
41-814-38 Confeo Premix P 28 HST NG ERP YBK UK 2020–present
41-814-39 Confeo Premix P 30 HST NG ERP YBK UK 2020–present
41-814-40 Confeo Premix P 35 HST NG ERP YBK UK 2020–present
Just want the most common ECA Confeo Premix HST faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes

All 38 documented codes

Tap any card for details

E01

Your boiler has failed to light because it isn't detecting a gas supply or a flame, leaving you without heating and hot water.

High DIY-safe £100-£280

What to check first

  1. Check that your gas emergency control valve (usually near the meter) is in the 'on' position.
  2. Verify if other gas appliances in your home, such as a hob, are working correctly to rule out a network issue.
  3. Press and hold the 'Reset' button for 3 seconds to see if the boiler restarts.

Parts commonly replaced

  • Ignition electrode
  • Gas valve
  • Flame sensing cable
  • Printed Circuit Board (PCB)

Related codes

Full explanation for E01
E02

Your boiler thinks it sees a flame even though it hasn't turned the gas on yet, causing it to shut down for safety.

High Engineer only £120-350

What to check first

  1. Press the Reset button once to see if the error clears
  2. Ensure there is no moisture or dampness around the boiler casing
  3. If the code returns immediately, turn off the electrical supply to the boiler and call a professional

Parts commonly replaced

  • Ionisation Electrode
  • Gas Valve
  • Printed Circuit Board (PCB)

Related codes

Full explanation for E02
E03

Your boiler has shut down because the internal water temperature has become too hot.

High DIY-safe £120-350

What to check first

  1. Check that at least one radiator (usually one without a thermostatic valve) is fully turned on.
  2. Ensure the blue and red water valves underneath the boiler are in the open position.
  3. Wait 10 minutes for the unit to cool down and then press the Reset button.

Parts commonly replaced

  • Circulation pump
  • Heat exchanger (chemical flush)
  • NTC Temperature sensors

Related codes

Full explanation for E03
E15

Your boiler has shut down because its internal temperature sensors are giving conflicting readings and can no longer monitor the heat safely.

High DIY-safe £100-190

What to check first

  1. Locate the Reset button on the boiler control panel
  2. Press and hold the Reset button for 3 seconds
  3. Wait for the boiler to restart; if the code returns, you must call a Gas Safe engineer

Parts commonly replaced

  • NTC Temperature Sensor (Flow)
  • NTC Temperature Sensor (Return)
  • Connecting Wiring Loom

Related codes

Full explanation for E15
E16

Your boiler has stopped working because it cannot detect the temperature of the water flowing into your heating system.

High DIY-safe £90-160

What to check first

  1. Press the 'Reset' button on the boiler control panel once
  2. Wait 5 minutes to see if the error code clears and the boiler fires up
  3. If the code returns immediately, do not attempt further repairs and contact a professional

Parts commonly replaced

  • Central Heating Flow NTC Sensor
  • Wiring harness / sensor connection

Related codes

Full explanation for E16
E17

Your boiler has shut down because it cannot detect any water temperature information coming back from your heating system pipes.

High DIY-safe £90-160

What to check first

  1. Locate the Reset button on the boiler control panel.
  2. Press and hold the Reset button for 3 to 5 seconds.
  3. Wait for the boiler to restart; if the code returns immediately, a professional repair is required.

Parts commonly replaced

  • Return Temperature Sensor (NTC Thermistor)
  • Sensor Wiring Harness

Related codes

Full explanation for E17
E18

Your boiler has shut down because it detected a sudden, abnormal spike in temperature that could lead to overheating.

High DIY-safe £100-220

What to check first

  1. Press the Reset button on the control panel to see if the error clears.
  2. Ensure all radiator valves are fully open to allow water to flow freely.
  3. Check that your system pressure is topped up between 1 and 1.5 bar.

Parts commonly replaced

  • NTC Temperature Sensor
  • Circulation Pump
  • Main Heat Exchanger (cleaning or replacement)

Related codes

Full explanation for E18
E33

Your boiler has stopped working because the sensor that monitors the temperature of the water returning to the unit is no longer communicating correctly.

High Engineer only £90-160

What to check first

  1. Press the Reset button once to see if the error clears
  2. Check if any nearby pipework is leaking onto the electrical sensors
  3. If the fault persists, book a Gas Safe registered engineer

Parts commonly replaced

  • NTC Return Temperature Sensor
  • Wiring harness / Sensor lead

Related codes

Full explanation for E33
E35

Your boiler has stopped working because it cannot correctly measure the temperature of the water leaving the unit.

High Engineer only £90-160

Parts commonly replaced

  • Flow Temperature Sensor (NTC)
  • Wiring Harness

Related codes

Full explanation for E35
E38

Your boiler has detected a recurring drop in water pressure which suggests there is a leak somewhere in your heating system or within the boiler itself.

High DIY-safe £100-350

What to check first

  1. Check all visible radiator valves and pipework for signs of dampness or dripping water.
  2. Top up the system pressure using the filling loop until the gauge reads between 1.0 and 1.5 bar.
  3. Press the 'Reset' button on the control panel to clear the lockout.

Parts commonly replaced

  • Automatic Air Vent
  • Expansion Vessel
  • Pressure Relief Valve
  • Internal seals or washers

Related codes

Full explanation for E38
Showing 11–20 of 38
E44

Your boiler has stopped working because the gas valve is not communicating correctly with the control system.

High Engineer only £220-£380

What to check first

  1. Press the Reset button once to see if the error clears
  2. Ensure your gas supply is active (e.g., check other gas appliances)
  3. If the fault returns after resetting, do not attempt further repairs and call a professional

Parts commonly replaced

  • Gas Valve
  • Printed Circuit Board (PCB)
  • Wiring loom

Related codes

Full explanation for E44
E64

Your boiler has experienced an internal electronics failure that has caused it to shut down for safety.

High Engineer only £280-450

What to check first

  1. Switch the boiler off at the main power isolation switch
  2. Wait 30 seconds
  3. Switch the power back on and check if the code clears

Parts commonly replaced

  • Main Printed Circuit Board (PCB)

Related codes

Full explanation for E64
E65

Your boiler's internal computer has encountered a critical electronic failure that it cannot automatically resolve.

High DIY-safe £180-450

What to check first

  1. Locate the power switch or fused spur next to your boiler
  2. Switch the power off and wait for 30 seconds
  3. Switch the power back on and see if the error clears

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • Wiring loom connectors

Related codes

Full explanation for E65
E80

Your boiler has shut down because it thinks the water returning to the unit is hotter than the water leaving it, which usually indicates a circulation problem or a faulty sensor.

High DIY-safe £120-220

What to check first

  1. Press the Reset button on the control panel to see if it was a temporary glitch.
  2. Ensure all radiator valves are fully open to allow water to flow correctly.
  3. Check that your system pressure is between 1.0 and 1.5 bar on the pressure gauge.

Parts commonly replaced

  • Return temperature NTC sensor
  • Supply temperature NTC sensor
  • Circulation pump

Related codes

Full explanation for E80
E82

Your boiler is repeatedly losing its flame and has locked itself out for safety.

High Engineer only £120-350

Parts commonly replaced

  • Ionisation electrode
  • Gas valve
  • Flame sensing lead
  • PCB

Related codes

Full explanation for E82
E83

Your boiler has shut down because the exhaust gases are getting too hot, indicating a potential blockage or buildup in the main heat exchanger.

High Engineer only £180-£550

Parts commonly replaced

  • Main Heat Exchanger
  • Flue Gas Sensor
  • Secondary Heat Exchanger

Related codes

Full explanation for E83
E98

Your boiler has detected an internal computer error that has caused it to stop working and lock itself for safety.

High Engineer only £250-450

What to check first

  1. Turn the boiler off at the main power switch
  2. Wait for 30 seconds
  3. Turn the power back on and press the reset button

Parts commonly replaced

  • Main PCB (Printed Circuit Board)
  • Wiring harness

Related codes

Full explanation for E98
E99

Your boiler has experienced an internal electronics failure that is preventing it from starting up correctly.

High Engineer only £280-450

What to check first

  1. Switch off the boiler's electrical power supply
  2. Wait for 30 seconds
  3. Switch the power back on and attempt to restart the unit

Parts commonly replaced

  • Main Printed Circuit Board (PCB)
  • Control Panel Housing

Related codes

Full explanation for E99
F05

Your boiler has stopped working because the fan that helps remove waste gases is not spinning correctly or communicating with the system.

High Engineer only £180-350

What to check first

  1. Press the Reset button once to see if the fault clears
  2. Ensure there is no debris blocking the external flue pipe (the white pipe on your outside wall)
  3. If the fault returns immediately, contact a Gas Safe registered engineer

Parts commonly replaced

  • Fan assembly
  • Wiring harness / Fan cable
  • Main PCB

Related codes

Full explanation for F05
F07

Your boiler has shut down because the exhaust gases have become too hot, which is a safety measure to prevent damage to the internal components.

High Engineer only £120-350

Parts commonly replaced

  • Heat Exchanger (cleaning or replacement)
  • Flue Gas Sensor
  • Main PCB

Related codes

Full explanation for F07
Showing 21–30 of 38
F10

Your boiler has stopped working because water isn't flowing through the system properly, often caused by a blockage or a faulty pump.

High DIY-safe £120-350

What to check first

  1. Check that all radiator valves are fully open
  2. Ensure the boiler pressure gauge is between 1.0 and 1.5 bar
  3. Press the reset button to see if the error clears

Parts commonly replaced

  • Circulation pump
  • Central heating filter
  • Main heat exchanger

Related codes

Full explanation for F10
F13

Your boiler has locked itself out because the reset button has been pressed too many times in a short period.

High Engineer only £80-250

Parts commonly replaced

  • Main Control PCB
  • Ignition Electrode
  • Gas Valve

Related codes

Full explanation for F13
F34

Your boiler has detected that the electricity supply coming into your home is too weak for it to operate safely, causing the system to shut down.

High Engineer only £100-350

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Voltage Regulator
  • External Power Supply Cable

Related codes

Full explanation for F34
F36

Your boiler has detected an issue with the stability or frequency of your home's electrical supply, causing it to shut down for safety.

High Engineer only £100-350

Parts commonly replaced

  • Printed Circuit Board (PCB)
  • Surge Protector

Related codes

Full explanation for F36
F37

Your boiler has stopped working because the water pressure is too low for the system to run safely.

High DIY-safe £0-120

What to check first

  1. Locate the filling loop (usually a silver flexible hose) underneath or near the boiler.
  2. Slowly open the valves until you hear water flowing and watch the pressure gauge.
  3. Close both valves tightly once the pressure reaches between 1.5 and 2.0 bar.

Parts commonly replaced

  • Water pressure sensor
  • Filling loop valve
  • Expansion vessel

Related codes

Full explanation for F37
F39

Your boiler is having trouble communicating with the sensors that monitor the temperature outside, which can prevent it from heating your home efficiently.

Low DIY-safe £90-160

What to check first

  1. Locate the Reset button on the boiler control panel.
  2. Press and hold the Reset button for 3 to 5 seconds.
  3. Wait to see if the error code clears and the boiler restarts normally.

Parts commonly replaced

  • Outdoor temperature sensor
  • Sensor wiring harness

Related codes

Full explanation for F39
F40

Your boiler has shut down because there is too much water pressure in the system, which could lead to leaks if not addressed.

Emergency DIY-safe £80-160

What to check first

  1. Check that the filling loop valves (the silver flexible hose) are fully closed.
  2. Locate a radiator and use a bleed key to release a small amount of water until the pressure gauge on the boiler drops to 1.5 bar.
  3. Restart the boiler to clear the fault code.

Parts commonly replaced

  • Filling loop valve
  • Expansion vessel
  • Water pressure sensor

Related codes

Full explanation for F40
F41

Your boiler is continuously trying to fill itself with water automatically, which can indicate a system leak or a sensor fault.

High Engineer only £120-280

Parts commonly replaced

  • Automatic filling valve
  • Water pressure sensor
  • Expansion vessel

Related codes

Full explanation for F41
F42

Your boiler is unable to top itself up with water because the filling process has timed out, likely due to low mains pressure or a part becoming stuck.

High DIY-safe £90-180

What to check first

  1. Check that your main stopcock is fully open and you have good water pressure at your kitchen tap.
  2. Inspect the boiler's pressure gauge to see if it is below 1.0 bar.
  3. Restart the boiler to see if the auto-filling cycle attempts to run again.

Parts commonly replaced

  • Automatic filling valve
  • Water pressure sensor
  • PCB

Related codes

Full explanation for F42
F43

Your boiler has tried to top itself up with water automatically but failed, meaning there isn't enough pressure for the system to run.

High DIY-safe £120-280

What to check first

  1. Check that your main cold water stopcock is fully open to ensure there is enough incoming pressure.
  2. Inspect the area around the boiler and radiators for any visible water leaks.
  3. Attempt to manually top up the system pressure using the external filling loop if one is installed.
  4. Restart the boiler to see if the error clears once pressure is restored.

Parts commonly replaced

  • Automatic filling valve
  • Water pressure sensor
  • Main PCB

Related codes

Full explanation for F43
Showing 31–38 of 38
F47

Your boiler has stopped working because it cannot detect a connection to the sensor that monitors water pressure.

High DIY-safe £120-190

What to check first

  1. Locate the Reset button on the boiler control panel.
  2. Press and hold the Reset button for 3-5 seconds.
  3. Wait to see if the error clears; if it returns immediately, the sensor or its wiring is likely faulty.

Parts commonly replaced

  • Water pressure sensor (transducer)
  • Wiring harness or connector

Related codes

Full explanation for F47
F49

Your boiler is having trouble 'talking' to your thermostat, which means it doesn't know when to turn your heating on or off.

High DIY-safe £100-250

What to check first

  1. Locate the main power switch for your boiler and turn it off for 30 seconds, then back on.
  2. Press and hold the 'Reset' button on the front boiler panel.
  3. Check if your room thermostat has batteries that need replacing.

Parts commonly replaced

  • Room thermostat
  • Receiver unit
  • Wiring harness

Related codes

Full explanation for F49
F50

Your boiler has lost communication with the temperature sensor in your hot water storage tank, meaning it cannot safely heat your water.

High Engineer only £90-180

What to check first

  1. Locate the Reset button on the boiler control panel
  2. Press and hold the Reset button for 3 seconds
  3. Wait to see if the error clears and the boiler restarts

Parts commonly replaced

  • NTC Storage Tank Sensor
  • Wiring harness / Sensor cable

Related codes

Full explanation for F50
F51

Your boiler has detected a problem with the sensor monitoring your solar heating system, which is causing the unit to stop operating.

Low DIY-safe £90-160

What to check first

  1. Locate the Reset button on the boiler control panel.
  2. Press and hold the Reset button for 3 seconds.
  3. Wait to see if the error clears and the boiler restarts.
  4. If the code returns immediately, contact a qualified engineer.

Parts commonly replaced

  • PT1000 Solar Sensor
  • Sensor wiring harness

Related codes

Full explanation for F51
F52

Your boiler has detected a problem with the sensor that monitors your hot water temperature, which is stopping your hot water from working correctly.

Medium Engineer only £90-160

Parts commonly replaced

  • Domestic Hot Water (DHW) Temperature Sensor (NTC)
  • Wiring Harness

Related codes

Full explanation for F52
F53

Your boiler has detected a problem with the sensor that monitors exhaust gas temperatures, causing it to shut down for safety.

High Engineer only £110-190

Parts commonly replaced

  • Flue gas temperature sensor (NTC)
  • Wiring harness
  • Main PCB

Related codes

Full explanation for F53
F81

Your boiler has detected that its internal temperature sensors are giving conflicting readings and has shut down to prevent overheating.

High Engineer only £90-180

Parts commonly replaced

  • Flow NTC Sensor
  • Return NTC Sensor
  • Wiring Harness

Related codes

Full explanation for F81
F201

Your boiler's internal computer brain is unable to talk to the display screen, meaning the system has stopped working to protect itself.

High Engineer only £180-450

Parts commonly replaced

  • Main PCB (Mainboard)
  • MMI Control Panel
  • Communication Ribbon Cable

Related codes

Full explanation for F201
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