Baxi Boiler Error Codes: Full UK Guide (2025)
Complete UK breakdown of Baxi boiler fault codes — causes, fixes, and typical repair costs for Duo-Tec, Platinum, 800, 600 and older models.
Baxi Boiler Error Codes: Full UK Guide (2025)
Baxi boilers (Duo-Tec, Platinum, EcoBlue, 600, 800, Neta-Tec) are among the most common heating systems found across London, Birmingham, Manchester, Liverpool, Glasgow, Edinburgh, and Bristol.
This comprehensive guide explains every major Baxi boiler error code, including causes, fixes, and typical UK repair costs.
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Most Common Baxi Error Codes (UK)
Below are the most frequent issues affecting Baxi boilers in 2025.
E119 — Low Water Pressure (Extremely Common)
Meaning: System pressure below safe operating level.
Fix:
- Repressurise to 1.2 bar
- Bleed radiators
- Check for leaks
Typical UK Cost: £0–£160
E133 — Ignition / Gas Supply Fault
Occurs frequently across the UK during cold weather or gas grid dips.
Causes:
- Frozen condensate
- Gas valve fault
- Flame sensor fault
- Blocked flue
Cost: £120–£320
E168 — PCB Voltage Fault
Meaning: Unstable power to PCB.
Fix:
- Check power supply
- Engineer diagnose PCB
Cost: £220–£480
E133 / E28 — Flame Failure
Causes:
- Low gas pressure
- Faulty electrode
- Blocked burner
Cost: £140–£300
Fan, Pump & Temperature Faults
E160 — Fan Fault
Requires engineer.
Cost: £180–£350
E110 — Overheat Lockout
Causes:
- Pump failure
- Blocked heat exchanger
- Sludge
Cost: £150–£320
E20 / E21 — Sensor Fault
Fix: Replace NTC sensor.
Cost: £80–£160
E78 — Water Flow Problem
Meaning: Poor circulation.
Fix: Pump check, flush system.
Cost: £140–£350
Ignition & Electrical Error Codes
E50 / E51 — Faulty PCB
Meaning: Communication failure or damaged PCB.
Cost: £250–£480
E40 / E41 — Flow/Return Temperature Sensor Fault
Fix: Replace thermistor.
Cost: £90–£160
Frozen Condensate Errors in UK Winter
E133 / E28 / E118 often appear during freezing temperatures.
Fix:
- Pour warm water on external pipe
- Insulate condensate pipe
Cost: £0–£120
Baxi Boiler Repair Costs (UK 2025)
| Fault | Typical UK Cost |
|---|---|
| Low pressure (E119) | £0–£160 |
| Ignition fault (E133) | £120–£320 |
| PCB failure (E168/E50) | £250–£480 |
| Fan replacement (E160) | £180–£350 |
| Pump repair | £180–£350 |
| Sensor replacement | £80–£160 |
| Frozen condensate | £0–£120 |
| Annual service | £70–£90 |
Should You Repair or Replace a Baxi Boiler?
Consider replacement if:
- Boiler is 12+ years old
- Repeated ignition faults
- PCB and fan issues occur together
- Repair costs exceed £500–£600
For peace of mind, consider:
Final Advice for UK Homeowners
Baxi boilers are reliable but commonly show faults like E119, E133, and E110. Cold UK winters increase ignition failures and frozen condensate issues.
To avoid unexpected breakdowns:
- Get an annual boiler service
- Protect your system with cover
- Fix pressure issues quickly
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