Ideal · Logic System2
L04 boiler fault code
Logic System2
Get a Gas Safe engineer
Free. Enter your postcode.
Renting? Report it to your landlord or housing provider first. They are responsible for gas safety and boiler repairs, and the repair should not cost you.
What L04 means
L04 indicates flow thermistor.
Safe check
Follow the user guide restart instruction once. Do not open the boiler or inspect wiring or sensors.
When to contact an engineer
The fault remains or returns after the user guide action; contact Ideal if the boiler is under warranty or arrange a Gas Safe registered engineer.
Safety notice
A boiler fault code alone is not a gas or carbon-monoxide emergency. If you smell gas, a CO alarm sounds, anyone feels unwell, or there is an unsafe flame, leave and call 0800 111 999 from outside.
Source and provenance
- Logic System2 User Guide · §1.9, printed p. 7 · L04 Flow Thermistor
user guide
10/2023 · UIN 237665 A01