BoilerFaultCodesThe 6 most common faults
01
Flame Lock-out High Engineer
Your boiler has stopped working because it cannot light the internal flame, which means you currently have no heating or hot water.
Full guide for Flame Lock-out02
E02-325 High Engineer
Your boiler has stopped working because a sensor that monitors water temperature is not sending the correct signal to the control system.
Full guide for E02-32503
E02-367 High Engineer
Your boiler has lost the ability to send electrical signals between its internal parts, meaning it cannot communicate correctly to start heating.
Full guide for E02-36704
E78-236 High Engineer
Your boiler is failing to detect the gas flow required to ignite, meaning it cannot produce heat or hot water because the internal gas supply component is not responding correctly.
Full guide for E78-23605
E02-372 High Engineer
Your boiler is failing to ignite because it cannot detect a flame, likely due to a faulty or dirty sensor that helps start the fire.
Full guide for E02-37206
E02-365 High Engineer
Your boiler's central control computer is experiencing an internal error, which has caused the system to shut down for your safety.
Full guide for E02-365on the Potterton Kingfisher MF RSL
ThermocoupleGas valvePCBSpark generatorNTC ThermistorWiring harness
Based on parts cited in our fault code database. Your engineer will confirm what's actually needed after diagnosis.
Call a Gas Safe engineer if…
- You can smell gas or see signs of a leak
- The Potterton shows an Emergency or High severity code
- The boiler keeps locking out after repeated resets
- You've tried the DIY checks and the fault hasn't cleared
- There's visible water leaking from the boiler
- The flame is yellow or orange instead of blue