Alpha boilers covered here
Alpha boilers are made by Alpha Heating Innovation (Alpha Therm Ltd). The fault codes on this site come from the error tables in Alpha's installation and servicing instructions for the E-Tec 28 and 33, the E-Tec Plus 28 and 33, and the InTec2 26CE, 30CE and 35CE combi boilers. Most codes mean the same thing across these ranges, but not every code appears in every manual. Where a code is only listed for certain models, the code page says so. If you have a different Alpha range, check the code against the manual for your exact boiler.
How Alpha fault codes appear
Alpha's tables list each fault as a plain number, such as 01 or 10, but the boiler display adds an E in front, so you will see E01 or E10. The manuals also describe a fault history inside the INFO menu, where past faults are stored with the same E prefix. An engineer will often check that history first, so write down the code exactly as it shows before you do anything else.
The A and B lights on older Alpha boilers
Some older Alpha boilers have no digital display and use lights marked A and B instead. Alpha's own FAQ explains that when the A and B lights flash alternately, the system pressure is too low and the gauge will usually be below 1 bar, outside the green area. Topping up through the filling loop should stop the lights flashing. For other light patterns, the user manual for your model is the best guide.
Common Alpha codes at a glance
| Code | What the manual says it means | First step |
|---|---|---|
| E01 | Ignition failure, no flame detected while lighting | Check the gas supply, then one reset |
| E02 | Overheat lockout | Gas Safe engineer |
| E03 | High flue temperature | Gas Safe engineer |
| E08 | Maximum number of resets reached | Stop resetting, call an engineer |
| E10 | Primary system pressure low | Top up with the filling loop |
| E37 | Supply voltage too low to run the boiler | Check the fused spur and power |
| E38 | Flame signal lost, boiler retries | Note when it happens |
| E43 | Repeated loss of flame signal | Gas Safe engineer |
| E60 | Pump stuck or electrical pump fault | Gas Safe engineer |
How to reset an Alpha boiler safely
Deal with the likely cause first, for example low pressure or a prepayment meter that has run out. Then press the reset button once and give the boiler a few minutes to light. If the same code returns, stop after two or three attempts. The E-Tec 28 and 33 manual lists E08 as the maximum number of resets, reached after five resets so repeated pressing will not clear a genuine fault and can leave the boiler locked out until an engineer attends.
Checking pressure and preventing repeat faults
Look at the pressure gauge once a month with the heating cold. If the needle has dropped below the green area, top up using our filling loop guide. In freezing weather, Alpha's FAQ suggests checking whether the condensate pipe has frozen and says you can usually thaw it yourself with warm water, which our frozen condensate pipe guide covers. A yearly service lets an engineer catch worn electrodes, failing pressure parts and flue problems before they leave you without heating.
When to call a Gas Safe registered engineer
Ignition and flame faults, fan, flue and pump faults, and any repair inside the casing are engineer jobs. Call one if a code keeps coming back, if water is leaking from the boiler, or if the pressure keeps dropping after a top-up. If you smell gas, turn the supply off at the meter if it is safe to do so, open the windows and call the National Gas Emergency Service on 0800 111 999. For other makes, see our full list of boiler brands.