Baxi E125 Fault Code Explained
Hertfordshire, Bedfordshire & Cambridgeshire
An E125 fault on a Baxi boiler indicates a circulation problem: water is not moving through the system as the boiler expects.
Check pressure and bleed the radiators first, then it is engineer work.
What E125 actually means
The boiler monitors flow and temperature. If water is not circulating properly it shuts down before the heat exchanger is damaged.
What you can safely check yourself
Check the pressure gauge. It should read 1 to 1.5 bar cold. If it is near zero, repressurise using the filling loop until it reaches 1.5 bar, then reset.
If it falls again within days, you have a leak. Stop topping it up and get it traced.
When to stop, and why
If pressure is correct and bleeding does not clear it, stop. Running a boiler with poor circulation is what turns a pump repair into a heat exchanger repair.
What causes it beyond the simple checks
A failed or weak pump, sludge restricting the heat exchanger, closed valves, or a failed sensor. Sludge is a frequent underlying cause and is dealt with by a power flush rather than by replacing parts repeatedly.
How Vantage can help
We are Gas Safe registered and cover Hertfordshire, Bedfordshire and Cambridgeshire, with an emergency line answered 24 hours a day.
Call us on 01462 506374. See also boiler repair.
Frequently asked questions
Is E125 serious?
It is the boiler protecting itself. Ignoring it gets expensive.
Can bleeding fix it?
Sometimes, if trapped air is the cause.
Why does sludge keep coming back?
Without a magnetic filter and inhibitor it will. We fit or check both.
Related fault codes
Other Baxi codes: Baxi E133 · Baxi E110
The same problem on other makes (circulation and flow faults): Vaillant F75 · Vaillant F23 · Vaillant F83
See also our guide to radiator not heating up, the full boiler advice section, and boiler repair.
In Baxi’s own words
Baxi’s published error-code list gives E125 simply as “Water circulation fault”. Everything else follows from that: the boiler is making heat and the system is not carrying it away.
When to call an engineer
If the fault keeps returning after a reset, it is telling you something is degrading rather than broken. Call 01462 506374 and we will diagnose it properly rather than swapping parts and hoping. Gas Safe registered 956889, 12 months on our own labour.
Need help today?
Call and speak to a person, any hour, any day of the year, or get a fixed price quote online.
Get a fixed price quote Call 01462 506 374Trusted & Accredited Professionals
What our customers say
Speak to a local engineer
Vantage Plumbing and Heating covers Hertfordshire, Bedfordshire and the surrounding areas. Call and talk to an engineer, or send us the details and we will come back to you with a price.
Gas Safe registered, number 956889. Emergency line answered 24/7.