- Boilers
- Gas boiler
E28
Baxi E28 on a gas boiler: flue gas NTC sensor fault
Risk level
Medium
Proceed carefully and stop if the check is unclear.
Urgency
High
Quick answer
Baxi E28 means the boiler reads the flue gas NTC sensor as faulty. Baxi gives no reset for this code: switch the boiler off and call the authorised service centre. Do not touch the flue.
Safety first
Stop and check this first
- Do not try to disconnect or bypass the flue sensor to make the boiler start: it protects the flue.
- If you smell gas: switch the boiler off, do not operate any electrical device or switch on lights, put out any flame, open the windows and leave; from outside, call your gas distributor's emergency number and the service centre. If you smell combustion fumes, switch the boiler off, ventilate and call the service centre.
Safe checks you can perform
- Switch off and note the code
- Boiler information menu
- Technician sensor measurement
Leave these tasks to a qualified professional
- Do not attempt this professional task: Flue NTC and wiring measurement
- Do not attempt this professional task: Flue check and final test
What a technician must be able to justify
Technician visit
These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.
These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.
Flue NTC and wiring measurement
What they doThe technician measures the sensor resistance with a multimeter and checks the connector and cable before replacing anything.
They must show youthe measured value against Baxi's curve.
In writingwhat was measured and what was replaced.
Flue check and final test
What they doAfter the repair, the technician checks the flue and that line 07 of the menu shows a sensible temperature.
They must show youthe boiler running with no code and the flue reading.
In writingthe test date and result.
Before accepting a part or repair
Nothing has been shown yet. Do not accept a part swap based on the code alone.
Follow these steps
Note: Follow the documented order. An error code identifies the affected system, but it does not prove by itself which part has failed.
Switch off and note the code
- Who:
- you.
- How:
- switch the boiler off and on once; do not leave it running with the code if it does not start.
- Result that matters:
- whether 28 is still on the display after switching on.
- If it clears and does not return:
- note the date; if it repeats, call the service centre.
- If it stays:
- Baxi says to call the authorised service centre.
- Evidence to keep:
- a photo of the display with the code and the date.
Evidence: Baxi Platinum Compact ECO, instrucciones de funcionamiento y mantenimiento para el usuario
Boiler information menu
- Who:
- you.
- How:
- hold the information key for at least 1 second, as Baxi describes, and look for line 07, flue sensor temperature.
- Result that matters:
- whether the boiler shows a flue temperature value or not.
- If it shows no sensible value:
- it supports the impossible reading; tell the technician.
- If it shows a value:
- note it; the technician will compare it with their measurement.
- Evidence to keep:
- a photo of the display on line 07.
Evidence: Baxi Platinum Compact ECO, instrucciones de funcionamiento y mantenimiento para el usuario
Technician sensor measurement
- Who:
- official service technician.
- How:
- measures the flue gas NTC sensor resistance and checks its connector and cable.
- Result that matters:
- whether the measured value is within the manufacturer's curve.
- If it is off:
- that confirms the sensor.
- If it is fine:
- it points to the connector, cable or board.
- Evidence to keep:
- a report with the measured value and any part replaced.
The sensor sits in the boiler's flue circuit; opening it is the gas technician's job.
Evidence: Baxi Platinum Compact ECO, instrucciones de funcionamiento y mantenimiento para el usuario
Still not solved
If the error persists, stop here. See what the technician must do and show you.
Where this code applies
A code is meaningful only inside the right product and version context.
Primary scope
- System
- Boilers
- Brand
- Baxi
- Product type
- Gas boiler
Known code variants
- 28
- Baxi 28
- Baxi E 28
- Error 28 Baxi
- Platinum Compact 28
What it means
On the Platinum Compact ECO, code 28 is a faulty flue gas NTC sensor, and Baxi's action is to call the service centre. That sensor measures flue gas temperature to protect the flue; 130 is a different code, overheating detected by the same sensor. With 28 the reading is impossible: a damaged sensor, a loose connector or a cut cable. The code does not say which, nor prove the sensor is broken.
Warnings and stop conditions
- Mediumeditorial warning
Do not try to disconnect or bypass the flue sensor to make the boiler start: it protects the flue.
Evidence: Baxi Platinum Compact ECO, instrucciones de funcionamiento y mantenimiento para el usuario
- Criticalsource verified
If you smell gas: switch the boiler off, do not operate any electrical device or switch on lights, put out any flame, open the windows and leave; from outside, call your gas distributor's emergency number and the service centre. If you smell combustion fumes, switch the boiler off, ventilate and call the service centre.
Evidence: Baxi Platinum Compact ECO, instrucciones de funcionamiento y mantenimiento para el usuario
Symptoms and causes
Probable causes · in order
- Damaged flue gas NTC sensorCommon
It is the condition Baxi names. It is confirmed only if the sensor's measured value is off its curve.
Evidence: Baxi Platinum Compact ECO, instrucciones de funcionamiento y mantenimiento para el usuario
- Sensor connector or cablePossible
A loose connector or damaged cable gives the same impossible reading; if the sensor measures fine, the cause is here.
Evidence: Baxi Platinum Compact ECO, instrucciones de funcionamiento y mantenimiento para el usuario
Virtual technician
Does E28 still appear after these checks?
Answer a few questions to narrow down the likely cause and the safest next action. Guidance only - it never replaces a professional.
Sources and technical references
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