Alpha Boiler Error Codes: Full UK Guide (2025)
Complete UK breakdown of Alpha boiler fault codes — causes, fixes, and typical repair costs for E-Tec, CB24, CB28, CD24 and older models.
Alpha Boiler Error Codes: Full UK Guide (2025)
Alpha boilers — including the E-Tec, CB24, CB28, CD24, CD28, and older Ocean models — are found across UK homes in London, Manchester, Birmingham, Liverpool, Leeds, Bristol, Glasgow, and Sheffield.
This comprehensive guide explains all major Alpha error codes, what they mean, how to fix them, and typical UK repair costs for 2025.
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Most Common Alpha Error Codes
E133 – Ignition Failure (Most Common)
The #1 Alpha boiler fault in the UK.
Meaning: Boiler attempted to ignite but failed.
Causes:
- Frozen condensate pipe (common in UK winters)
- Faulty ignition electrode
- No gas supply or low gas pressure
- Blocked burner or jets
- Gas valve failure
- Air in gas line
Fix:
- Thaw frozen condensate pipe with warm water
- Check gas supply and meter credit
- Reset boiler
- Engineer: check electrode, gas valve, and burner
Typical UK Cost: £120–£320
E110 – Overheat / Safety Lockout
Meaning: Temperature exceeded safe limit.
Causes:
- Pump failure or stuck pump
- Blocked heat exchanger
- System sludge buildup
- Low water flow
- Faulty overheat thermostat
Cost: £150–£350
E125 – Flow Temperature Sensor Fault
Temperature sensor not reading correctly.
Fix: Replace flow temperature sensor (NTC).
Cost: £80–£160
E01 – PCB Fault / Communication Error
Meaning: Control board cannot communicate properly.
Causes:
- PCB failure
- Water damage to electronics
- Electrical fault
- Wiring issue
Fix: Engineer required to diagnose and replace PCB.
Cost: £250–£480
E20 – Low System Pressure
Very common, especially after bleeding radiators.
Fix:
- Repressurise system to 1.0–1.5 bar using filling loop
- Check for visible leaks
- Bleed radiators if needed
Cost: £0–£160
Additional Alpha Fault Codes
E119 – Low Pressure (Similar to E20)
System pressure below safe operating level.
Cost: £0–£150
E128 – Flame Loss During Operation
Causes:
- Low gas pressure
- Faulty flame sensor
- Burner debris
- Unstable gas supply
Cost: £120–£280
E160 – Fan Speed Fault
Fan not reaching correct speed or stuck.
Fix: Replace fan assembly.
Cost: £180–£350
E118 – Air Pressure Switch Fault
Flue or ventilation issue detected.
Causes:
- Blocked flue
- Faulty air pressure switch
- Fan not working correctly
Cost: £140–£320
E117 – Low Pressure Warning
Similar to E20 and E119.
Cost: £0–£150
E168 – PCB Voltage Fault
Unstable power supply to control board.
Cost: £220–£480
Alpha E-Tec Specific Issues
The Alpha E-Tec range commonly shows:
- E133 during cold weather (frozen condensate)
- E110 when pumps fail or heat exchangers block
- E20 with system leaks or after maintenance
- E125 with faulty temperature sensors
Frozen Condensate Pipe (UK Winter)
Many Alpha faults (especially E133) occur when external condensate pipes freeze during UK winters.
Fix:
- Pour warm (not boiling) water over the frozen pipe
- Wait for ice to melt and water to drain
- Reset boiler once thawed
- Insulate the pipe with foam lagging to prevent recurrence
Cost: £0–£80
Alpha Boiler Repair Costs (UK 2025)
| Fault | Typical UK Cost |
|---|---|
| Low pressure (E20/E117/E119) | £0–£160 |
| Ignition fault (E133) | £120–£320 |
| Overheat (E110) | £150–£350 |
| Flame loss (E128) | £120–£280 |
| Fan fault (E160) | £180–£350 |
| PCB replacement (E01/E168) | £250–£480 |
| Sensor replacement (E125) | £80–£160 |
| Pump replacement | £180–£350 |
| Annual service | £70–£90 |
London and South East costs typically 10–20% higher. Scotland, Midlands and North West usually cheaper.
When to Call a Gas Safe Engineer
You MUST call a Gas Safe registered engineer if the issue involves:
- Gas valve or gas supply issues
- PCB or control board faults
- Internal burner or ignition components
- Fan assembly
- Heat exchanger problems
- Flue or combustion issues
- Any error code that persists after reset
Never attempt DIY repairs on gas-related components — it's illegal and extremely dangerous.
Stay protected year-round:
Should You Repair or Replace?
Consider boiler replacement if:
- Boiler is 12+ years old
- Repeated E133, E110, or E01 faults
- Multiple components failing together
- PCB replacement needed on older model
- Repair costs exceed £500–£600
- Heat exchanger is beyond economical repair
For peace of mind and protection:
Final Advice for UK Homeowners
Alpha boilers are reliable but commonly show faults like E133, E110, E20, and E125 — especially during UK winter when condensate pipes freeze and system pressure drops.
To minimize breakdowns:
- Get an annual boiler service (£70–£90)
- Maintain correct system pressure (1.0–1.5 bar)
- Insulate external condensate pipes before winter
- Address pressure drops and faults quickly
- Keep vents and flues clear of obstructions
Protect your home with: