BoilerFaultCodesThe 6 most common faults
01
ERROR CODE 8 High DIY-safe
Your boiler is unable to drain away the water it creates during normal operation, causing it to block up and stop working to prevent internal damage.
What to try first
Locate the plastic condensate pipe exiting your home, usually found outside near the wall.Check for any visible blockages like frozen ice, leaves, or debris at the end of the pipe.If frozen, pour warm (not boiling) water over the pipe to melt the ice, then press the boiler's reset button.
02
Automatic Shutdown High DIY-safe
Your boiler has stopped working because the pipe that drains away waste water is blocked, either by frozen water or a build-up of debris.
What to try first
Locate the white plastic condensate pipe leading outside from your boiler.If it is winter, pour warm (not boiling) water over the external section of the pipe to thaw any ice.Ensure the end of the pipe is not submerged in standing water or blocked by debris.
03
ERROR CODE 1 High Engineer
Your boiler has stopped working for safety reasons and needs to be restarted, but if it keeps happening, an internal fault is preventing it from firing up.
Full guide for ERROR CODE 104
ERROR CODE 2 High Engineer
Your boiler has detected that it is running too hot and has automatically shut down to prevent damage to its internal parts.
Full guide for ERROR CODE 205
ERROR CODE 3 High Engineer
Your boiler has detected an issue with the water pressure or the flow regulation system, causing it to shut down to prevent damage.
Full guide for ERROR CODE 306
ERROR CODE 4 High Engineer
Your boiler has detected an issue with its internal airflow or ventilation system, preventing it from safely starting up.
Full guide for ERROR CODE 4on the Ideal Excel HE
Condensate trapCondensate pipeworkSiphonIgnition electrodeGas valvePrinted circuit board (PCB)
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 Ideal 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