S.03
FAULT CODE
Vaillant
Heating Mode — Ignition Sequence
Low Severity
DIY Check Possible
Status code: The boiler is going through its ignition sequence. Normal operating status.
Step-by-Step Fix Guide
-
Step 1
No action required — wait for the burner to light
-
Step 2
If ignition does not occur within 30 seconds, the boiler may show a fault code
Gas Safe Reminder
Work on gas appliances must be carried out by a Gas Safe registered engineer. The steps above cover safe checks a homeowner can perform - any internal component replacement requires a qualified professional. If in doubt, always call an engineer.