What is this?
Electric boilers heat water using an immersion element and circulate it through radiators or provide domestic hot water. When an electric boiler stops working, you may lose both heating and hot water. Electric boilers are common in flats and properties without a gas supply.
Common causes
- Tripped MCB or RCD on the boiler's dedicated circuit
- Faulty heating element inside the boiler
- Thermostat failure — not calling for heat
- Motorised valve stuck or failed
- Low water pressure causing the boiler to lock out
- PCB (printed circuit board) fault in the boiler
Is it dangerous?
Electric boilers do not carry the same carbon monoxide risk as gas boilers. However, a fault that causes the circuit to trip could indicate an electrical issue such as an earth fault or short circuit. Do not keep resetting the MCB if it trips repeatedly.
Can I fix it myself?
Check the consumer unit for a tripped MCB on the boiler circuit (usually 32A or 40A). Check the boiler pressure gauge — most electric boilers need at least 1 bar of pressure. Check the boiler display for error codes and consult the manual. Make sure the thermostat is set correctly and the timer is on.
When to call an electrician
Call an electrician if the boiler's MCB trips when you turn it on, if the boiler displays an error code you cannot resolve, if there is no hot water despite the boiler appearing to run, or if you have no heating during cold weather and need urgent assistance.
What will an electrician do?
Test the dedicated boiler circuit and supply
Check boiler error codes and diagnose the fault
Test the heating element for continuity and earth leakage
Inspect the thermostat, sensors, and PCB
Check motorised valves and the water circulation system
Replace faulty components and reset the boiler
Typical cost
£100 – £350
Straightforward electrical faults are at the lower end. PCB replacements or new heating elements can be expensive depending on the boiler model.
