Common problems guide

The most common Alpha E-Tec 33 problems

The faults most likely to send a Alpha E-Tec 33 into lockout — with plain-English causes, what to check first, estimated repair costs and whether you need a Gas Safe engineer.

34 documented codes
6 most common
1 DIY-safe checks
5 engineer needed

The 6 most common faults

01
10 High DIY-safe

Your boiler has stopped working because the water pressure inside the heating system has dropped too low.

What to try first

Locate the internal filling loop beneath your boiler.Open the small valve or tap to allow cold mains water into the system.Watch the pressure gauge on the front of the boiler until the needle reaches the green zone (usually 1.0 to 1.5 bar).Close the valve tightly to stop the flow.

Est. cost
£80-150
Parts
Filling loop, Pressure relief valve, Pressure sensor
Full guide for 10
02
E03 High Engineer

Your boiler has detected that the flue gases are becoming too hot, so it has safely shut itself down to prevent any damage.

Est. cost
£120-250
Parts
Flue thermostat, PCB, Heat exchanger
Full guide for E03
03
E38 High Engineer

Your boiler has stopped working because it cannot detect a flame, meaning it is currently unable to safely heat your home or water.

Est. cost
£150-300
Parts
Ignition electrode, Flame rectification probe, Gas valve
Full guide for E38
04
01 High Engineer

Your boiler is failing to light the burner, meaning it cannot provide you with any heating or hot water until the issue is resolved.

Est. cost
£120-250
Parts
Ignition electrode, Gas valve, PCB
Full guide for 01
05
02 High Engineer

Your boiler has detected that it is getting too hot and has automatically switched itself off to prevent any damage.

Est. cost
£120-250
Parts
NTC sensor, Circulation pump, Heat exchanger
Full guide for 02
06
04 High Engineer

Your boiler has lost the secure electrical connection required to safely control its internal gas supply, preventing it from firing up.

Est. cost
£120-250
Parts
Gas valve assembly, Wiring harness
Full guide for 04
Parts most often replaced

on the Alpha E-Tec 33

Filling loopPressure relief valvePressure sensorFlue thermostatPCBHeat exchanger

Based on parts cited in our fault code database. Your engineer will confirm what's actually needed after diagnosis.

Call a Gas Safe engineer if…

  • You can smell gas or see signs of a leak
  • The Alpha shows an Emergency or High severity code
  • The boiler keeps locking out after repeated resets
  • You've tried the DIY checks and the fault hasn't cleared
  • There's visible water leaking from the boiler
  • The flame is yellow or orange instead of blue
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See the full 34-code list for the Alpha E-Tec 33

Related guides

Boiler losing pressure → No hot water → When to replace → Symptom checker →