BoilerFaultCodesAlpha E04 Fault Code
The Alpha E04 fault code means: your boiler is struggling because it cannot detect enough water flowing through its internal system, which prevents it from safely heating your home.. It appears on 13 Alpha models in our database.
Technical description: Inadequate circulation / No water
DIY fix possible
Check your boiler's pressure gauge on the front panel; it should be between 1.0 and 1.5 barIf the pressure is below 1.0 bar, locate the filling loop hose underneath the boilerOpen the valves on the filling loop to allow cold mains water in until the needle reaches 1.5 bar, then securely close the valves
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Gas Safe Register →Alpha models that show the E04 fault code
Click a model for the full fault code list and model-specific repair notes.
- C25 Xtraflame Repair: £80-150
- Cd13r Repair: £80-150
- CD24 Repair: £0-120
- CD28 Repair: £0-£120
- H25 Xtraflame Repair: £80-150
- Intec 28GS Repair: £80-150
- Intec 40GS2 Repair: £120-300
- Intec 50CS Repair: £80-150
- Intec2 25 28XE Repair: £150-250
- Intec2 30SE Repair: £150-250
- Pro Tec 24 Repair: £80-120
- Pro Tec Plus Repair: £80-120
- SY Repair: £80-150
Source
Alpha E04 fault code information on this page is sourced and cross-checked against the official Alpha service / installation manuals for each affected model.
Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed 27 April 2026