- Boilers
- Gas boiler
E125
Baxi E125 on a gas boiler: no circulation safety lockout
Risk level
High
Professional inspection is recommended.
Urgency
High
Quick answer
Baxi E125 means the boiler stopped because water was not circulating, detected by a temperature sensor. Check the pressure on the gauge, make sure radiator valves are open and reset once by holding reset for 2 seconds.
Safety first
Stop and check this first
- Baxi allows 5 consecutive resets and then forces a 15 minute wait. If 125 returns with good pressure and open valves, stop resetting: the boiler is protecting itself from heating water that is not moving.
- 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
- Pressure on the gauge
- Open radiator valves and one reset
- Technician diagnosis of circulation
Leave these tasks to a qualified professional
- Do not attempt this professional task: Pump flow test
- Do not attempt this professional task: Temperature sensor measurement
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.
Pump flow test
What they doThe technician checks the pump turns and moves water through the heat exchanger and looks for blockages or air.
They must show youthe pump running and a stable flow and return temperature difference.
In writingthe cause found and what was repaired.
Temperature sensor measurement
What they doIf there is flow, the technician measures the temperature sensor with a multimeter against Baxi's specification.
They must show youthe measured value against the manufacturer's table.
In writingthe part number replaced and why.
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.
Pressure on the gauge
- Who:
- you.
- How:
- with the system cold, read the boiler pressure gauge. Baxi asks for 1 to 1.5 bar when cold. Do not open the casing.
- Result that matters:
- whether the needle sits between 1 and 1.5 bar or below it.
- If it is below 1 bar:
- Baxi says to top up slowly with the boiler filling tap and then bleed the radiators; then see whether 125 comes back.
- If the pressure is correct:
- lack of water does not explain the code; do not add more.
- Evidence to keep:
- a dated photo of the gauge and a note each time you have to top up.
Evidence: Baxi Platinum Compact ECO, instrucciones de funcionamiento y mantenimiento para el usuario
Open radiator valves and one reset
- Who:
- you.
- How:
- open the radiator valves and thermostatic valves; then hold reset for at least 2 seconds, as Baxi says for 125.
- Result that matters:
- whether the boiler starts and the radiators warm up evenly.
- If it heats and 125 does not return:
- the cause was in the system; note it.
- If 125 returns with correct pressure and open valves:
- it rules out the simple system causes; call the service centre.
- Evidence to keep:
- a photo of the code and the pressure and a note of which valves were closed.
Evidence: Baxi Platinum Compact ECO, instrucciones de funcionamiento y mantenimiento para el usuario
Technician diagnosis of circulation
- Who:
- official service technician.
- How:
- checks the pump moves water, bleeds the air and measures the temperature sensor the control relies on.
- Result that matters:
- whether there is real flow and whether the sensor reads the same as the water temperature.
- If there is no flow:
- that confirms a stuck pump, air or a blockage.
- If there is flow and the sensor reads wrongly:
- that confirms the sensor or its wiring.
- Evidence to keep:
- a report with the flow check, the sensor reading and any part replaced.
The pump and sensors are inside the boiler, with mains voltage and next to the gas side: this is the 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
- 125
- Baxi 125
- Baxi E 125
- Error 125 Baxi
- Platinum Compact 125
What it means
On the Platinum Compact ECO, code 125 is the safety lockout for lack of circulation, and Baxi specifies the check is done with a temperature sensor: the boiler sees the water temperature rising too fast because it is not moving. It can come from air, low pressure, closed valves in the system, a pump that does not move water or a sensor reading wrongly. The code does not say which.
Warnings and stop conditions
- Highsource verified
Baxi allows 5 consecutive resets and then forces a 15 minute wait. If 125 returns with good pressure and open valves, stop resetting: the boiler is protecting itself from heating water that is not moving.
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
- Low pressure or air in the systemCommon
If the gauge shows under 1 bar when cold or radiators gurgle, water does not circulate well and the boiler cuts out.
Evidence: Baxi Platinum Compact ECO, instrucciones de funcionamiento y mantenimiento para el usuario
- Closed radiator valves or thermostatic valvesPossible
If many radiator valves are closed, the boiler has nowhere to move water; it shows because the fault began after rooms were shut off.
Evidence: Baxi Platinum Compact ECO, instrucciones de funcionamiento y mantenimiento para el usuario
- Pump or temperature sensorPossible
With correct pressure and open valves, a pump that does not push water or a sensor reading wrongly remain as suspects; the technician separates them.
Evidence: Baxi Platinum Compact ECO, instrucciones de funcionamiento y mantenimiento para el usuario
Virtual technician
Does E125 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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