Baxi Boiler Fault Codes
Gas Safe registered fault diagnosis for Baxi 600, 800, Platinum+, and Duo-tec models. E168, E119, E133, E28, E160 — all explained with repair costs and safe homeowner checks.
Understanding Baxi boiler fault codes
Baxi is one of the UK's oldest boiler manufacturers, with a large installed base across South London rental properties and residential homes. The 600, 800, and Platinum+ ranges use E-number fault codes displayed on the digital panel when the boiler locks out or detects a problem.
This guide covers the five most commonly searched Baxi fault codes, with technical explanations of what each fault means, what causes it, and what a Gas Safe engineer will do to fix it. Reion Miller (Gas Safe 919881) carries Baxi parts and handles Baxi boiler repairs across South London.
Baxi fault codes explained
Ignition lockout
The boiler attempted to ignite multiple times but could not establish a stable flame. The most common Baxi fault across all models.
Low water pressure
System pressure has dropped below the minimum operating threshold. Usually resolves with a repressurise — the most homeowner-safe Baxi fault.
Gas supply fault
The boiler cannot detect a gas supply or the gas valve has not operated correctly. Requires a Gas Safe engineer — do not attempt to reset repeatedly.
No water circulation
The pump is not circulating water through the system, or the flow sensor cannot detect movement. Common on boilers over 8 years old.
Fan / flue fault
The PCB cannot confirm the fan is running at the correct speed, or the air pressure switch has not triggered during the proving sequence.
Baxi boiler fault code table
Extended fault code reference for common Baxi 600, 800, and Platinum+ models.
| Code | Meaning | Common cause | Action |
|---|---|---|---|
| E119 | Low water pressure | System pressure below 0.5 bar | Repressurise to 1.2–1.5 bar (homeowner safe if no leak) |
| E168 | Ignition lockout | No flame detected after multiple attempts | Gas Safe engineer required |
| E133 | Gas supply fault | No gas or gas valve failure | Gas Safe engineer — do not reset repeatedly |
| E28 | No water circulation | Pump failure, airlock, blocked circuit | Gas Safe engineer required |
| E160 | Fan / APS fault | Fan motor failure, blocked flue, APS failure | Gas Safe engineer required |
| E131 | Gas valve fault | Gas valve not responding correctly | Gas Safe engineer — gas valve replacement likely |
| E110 | Overheating | Limescale, pump failure, blocked circuit | Gas Safe engineer — allow to cool first |
| E125 | Pump overrun / overheat | System overheating, pump running after shutdown | Gas Safe engineer |
| E20 | NTC sensor fault | Flow or return thermistor failure | Gas Safe engineer |
| E50 | DHW sensor fault | Domestic hot water thermistor failure | Gas Safe engineer |
Why Baxi boilers fault more often in London
Baxi boilers are common throughout South London's rental housing stock — particularly across Wandsworth, Lewisham, Lambeth, Southwark, and Bromley. They are cost-effective, reliable boilers, but South London's hard water shortens service intervals significantly.
Thames Water supplies water with some of the highest calcium concentrations in England. Inside a Baxi boiler, this deposits as limescale on the heat exchanger over years. The result: restricted water flow, ignition faults (E168), overheating (E110), pump failures (E28), and heat exchanger failures that annual servicing would have prevented.
Reion recommends fitting a Fernox TF1 or Adey MagnaClean magnetic filter at installation and running an annual service on every Baxi boiler in South London. Without this, E168 and E28 faults on 8–12 year old Baxi boilers are predictable.
Baxi boiler fault code questions
How do I reset a Baxi boiler after a fault code?
Why does my Baxi boiler keep showing fault codes in London?
Can I fix a Baxi boiler fault code myself?
How much does a Baxi boiler repair cost in London?
Which Baxi boiler models are most common in South London?
Baxi fault code showing on your boiler?
Reion is Gas Safe registered (919881), carries Baxi parts, and serves all of South London. Fixed price after the £80 diagnostic — no obligation to proceed.
