Baxi Boiler Fault Codes: Quick Guide & What To Do Next

Q: Is it safe to reset my Baxi boiler?

Yes—one reset after a simple check like topping pressure is reasonable. Do not repeatedly reset a boiler that instantly locks out; call a Gas Safe engineer.

Q: What pressure should my Baxi boiler be at?

Most Baxi boilers should read around 1.0–1.5 bar when cold. If it sits at 0.5–0.7 bar or keeps dropping, get it checked.

Q: Why does my boiler keep losing pressure?

Common reasons include small leaks, a faulty expansion vessel, or a weeping pressure relief valve. If you are topping up often, book a diagnosis.

Q: Do I need a powerflush or just a chemical clean?

Heavy sludge and cold radiator bottoms often justify a powerflush. For mild sludge or maintenance, a chemical clean plus inhibitor may be enough. We assess on site.

Q: How often should my boiler be serviced?

Annually. It keeps your boiler safe and efficient and protects warranties.

Tips Boiler & Heating Faults

When a Baxi boiler stops and flashes an error, it’s usually trying to protect itself or tell you where to look. This guide explains the most common Baxi fault codes, the simple checks you can do safely, and when to call a Gas Safe engineer.

Need help now? OSO Group Engineers repair Baxi boilers same day across Greater London, Kent, Sheffield, Birmingham, Leeds & more. Fixed fair pricing, insured work, and Gas Safe engineers.
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Quick Reference: Common Baxi Boiler Fault Codes

Code	Meaning	Safe homeowner checks
E119	Low system water pressure	Gauge should read ~1.0–1.5 bar (cold). Top up via filling loop, then reset the boiler. If pressure keeps dropping, you may have a leak—call an engineer.
E133	Ignition / gas supply fault	Check other gas appliances; ensure gas supply is on. Try one reset. If it returns, call a Gas Safe engineer.
E110	Overheat	Feel radiators (carefully) for airlocks/cold spots; bleed if confident; make sure all valves are open. If it returns—stop using and book a visit.
E125	Circulation fault	After topping to 1.0–1.5 bar, check if radiators heat evenly. Persistent lockouts = pump/filter issue—engineer required.
E131	Flue temperature high	Don’t use the boiler. Condensate/flue route may be restricted—engineer visit needed.
E156	Mains under-voltage	Avoid extension leads/power strips. If recurring, get the supply checked (and book service if faults persist).
E160 / E161	Fan / fan wiring fault	Power-cycle once. If you hear unusual noises or it relocks, book service.
E167 / E168	PCB / electronics lockout	One reset is fine. If it returns, it needs diagnosis.
E20	CH flow NTC fault	Sensor/wiring issue—generally needs an engineer.
E28	Flue NTC fault	Sensor/flue-related—book an engineer.
E09 / E15	Gas valve fault/command error	Do not attempt DIY on gas components. Call a Gas Safe engineer.
E193	Circulation error detected	Re-check pressure; if noisy pump or frequent lockouts, book service.
H.01.xx (status)	Temporary protection/comms status	Often self-clears after cool-down. If it repeats frequently, arrange a service.

Tip: Baxi uses “E” codes for lockouts and “H.01.xx” for temporary statuses that may clear by themselves. Model-specific code lists are found in each boiler’s manual.

Step-By-Step: Safely Top Up Low Pressure (E119)

Turn off heating and let the system cool.
Check the pressure gauge on the front—aim for ~1.0–1.5 bar when cold.
Find the filling loop (usually a silver braided hose with two small valves).
Open both valves slowly until pressure rises to ~1.2 bar.
Close both valves fully and reset the boiler.
If pressure keeps dropping over hours/days, you likely have a leak—book an engineer.

If you see water anywhere around the boiler, pipes, or radiators, turn the boiler off and call us.

How To Reset a Baxi Boiler (General)

Press and hold the Reset button (or turn the selector to Reset) for a couple of seconds.
Allow the boiler to start its ignition sequence.
If the same code returns repeatedly, don’t keep resetting—book a Gas Safe engineer.

When To Stop and Call a Gas Safe Engineer

Smell gas, suspect a flue/combustion issue, or E133 persists after confirming supply.
Repeated overheat (E110), circulation faults (E125/E193), fan errors (E160/E161), PCB errors (E167/E168), or sensor faults (E20/E28).
Pressure drops repeatedly (E119 returning).
Any gas valve faults (E09/E15)—no DIY on gas components.

Preventive Tips to Avoid Future Lockouts

Annual service by a Gas Safe engineer (protects warranty, keeps efficiency high).
Keep pressure around 1.2 bar cold; check monthly.
Bleed radiators if you hear gurgling or have cold tops.
Fit/clean a magnetic filter and ensure the system has correct inhibitor levels.
In freezing weather, lag your condensate pipe (especially outdoors) to prevent ice blockages.

Baxi Boiler Fault Codes: Expanded Explanations

E119 — Low Pressure

Your sealed system has lost water. Top to ~1.2 bar cold, reset, and monitor. Frequent drops suggest a leak (radiator valves, towel rails, pressure relief valve, or internal). Book a leak check if it falls again.

E133 — Ignition / Gas Supply

Can be low gas pressure, frozen condensate, or ignition components. Confirm gas supply and try one reset. If it returns, it’s a Gas Safe job.

E110 / E125 / E193 — Overheat & Circulation

Often air, sludge, stuck pump, blocked filter, or closed valves. Don’t keep resetting an overheating boiler—have circulation checked and system cleaned if needed.

E160 / E161 — Fan / Wiring

The boiler can’t prove safe airflow. Needs electrical/fan diagnosis and sometimes a new fan or harness.

E167 / E168 — PCB / Electronics

Electronics detected a fault or previous lockout state. Requires proper testing; don’t swap parts at random.

E20 / E28 — NTC Sensors

Temperature sensors that feed the PCB. Faults can be the sensor, wiring, or the board. Engineer tests resistance and wiring continuity.

E09 / E15 — Gas Valve

Command/positioning issues. Gas component work must be done by a Gas Safe engineer only.

Book a Same-Day Baxi Boiler Repair

OSO Group Engineers fix Baxi Duo-tec, Platinum, 200–800 series and more. We offer clear, fair pricing (call-out + hourly or fixed), and aim for ~1-hour arrival in covered areas.

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FAQs

Do you really operate 24/7?

Yes. Our operators answer calls day and night, 365 days a year, and we prioritise emergencies.

What areas do you cover?

We cover all of Greater London—Central, North, East, South, and West—every borough plus nearby counties. Examples in London: Westminster, City of London, Camden, Islington, Kensington & Chelsea, Hammersmith & Fulham, Brent, Ealing, Hounslow, Richmond upon Thames, Hillingdon, Harrow, Barnet, Enfield, Haringey, Waltham Forest, Hackney, Tower Hamlets, Newham, Redbridge, Barking & Dagenham, Havering, Southwark, Lambeth, Wandsworth, Merton, Sutton, Croydon, Bromley, Lewisham, Greenwich, Bexley, Kingston upon Thames.
We also serve Kent (e.g., Dartford, Bexleyheath, Orpington, Sevenoaks, Swanley, Gravesend, Medway), and many other UK areas on request (including parts of Surrey, Essex, Hertfordshire, and Berkshire). If you’re just outside these areas, contact us—we can usually arrange a same-day or next-day visit.

How fast can an engineer get to me?

Typically 60–90 minutes in London traffic. We’ll confirm an ETA on the call and keep you updated.

Is there a call-out fee? How do you price work?

Yes—transparent call-out plus hourly or fixed-price options depending on the job. You’ll see rates before we attend.

Can I get an exact quote before you arrive?

For many faults we can give a firm price range by phone with photos/video. After diagnosis on site we confirm a fixed price before work begins.

Are your engineers qualified and insured?

Yes. Boiler and gas work is carried out by Gas Safe registered engineers. We hold public liability insurance and provide digital job reports/invoices.

Do you handle residential and commercial jobs?

Yes—we work in houses, flats, shops, offices and plant rooms, including landlord and managing-agent jobs.

Is it safe to reset my Baxi boiler?

Yes—one reset after a simple check (like topping pressure) is reasonable. Don’t repeatedly reset a boiler that instantly locks out; call an engineer.

What pressure should my Baxi boiler be at?

Around 1.0–1.5 bar cold (most models). If it sits at 0.5–0.7 bar or keeps dropping, get it checked.

Why does my boiler keep losing pressure?

Small leaks, a faulty expansion vessel, or a weeping pressure relief valve. If you’re topping up often, book a diagnosis.

Do I need a powerflush or just a chemical clean?

If radiators are cold at the bottom and water is dirty/magnetic filter full of sludge, a powerflush may be justified. Mild sludge or maintenance often suits chemical clean + inhibitor. We assess on site.

How often should my boiler be serviced?

Annually. It keeps your boiler safe, efficient, and protects warranties.

Need help in UK?

We provide same-day Ideal boiler diagnostics and repair across Greater London, and many UK areas—transparent call-out plus hourly or fixed pricing, 24/7 emergency response.

//CONTACT US

Need help fast?

24/7 emergencies, ~1-hour ETA. Certified plumbing, heating/boiler, drainage, gas and electrical engineers—transparent pricing, fully insured, UK-wide. Call or book online.

CALL NOW

See Prices & Book