BoilerFaultCodesYour boiler has lost its electrical power supply or experienced a sudden interruption, causing it to shut down safety.
Book a Gas Safe engineer within 24–48 hours. Your boiler may be unsafe or could break down completely if left.
Technical description: Power supply has been interrupted.
What causes this fault?
This fault occurs when the boiler’s electronic brain suddenly loses its electrical connection, causing the unit to shut down instantly for safety. It is usually triggered by a blown internal fuse or a failure within the main circuit board that prevents power from flowing through the system. In some cases, an external issue like a tripped circuit breaker or a loose wire in the wall switch can also be the root cause.
This fault is slightly more common during stormy weather or winter months when power surges and local grid instability are more frequent.
DIY fix possible
Check if there has been a local power cut in your street or homeCheck your property's main fuse box (consumer unit) to see if a circuit breaker has trippedEnsure the boiler’s fused spur switch (usually near the boiler) is turned onTry resetting the boiler by turning the selector knob to the 'Reset' position for 5 seconds
Find a Gas Safe engineer
Search the official register for a qualified engineer in your area.
Gas Safe Register →Protect yourself from future repair bills
A boiler cover plan would cover faults like 04 — no call-out fees, no surprises.
Affiliate links — we may earn a commission at no extra cost to you.
Glow-worm Energysaver Combi 2 80 100 is discontinued — time for a new one?
Parts for discontinued models can be hard to find and expensive. A new A-rated boiler could save you money on both repairs and energy bills.
Affiliate links — we may earn a commission at no extra cost to you.