F.78
FAULT CODE
Vaillant
DHW Outlet Sensor Interruption
Medium Severity
Engineer Required
There is an interruption to the domestic hot water outlet sensor when connected to an external controller. Usually a wiring issue.
Step-by-Step Fix Guide
-
Step 1 Engineer only
Call a Gas Safe engineer to inspect the DHW sensor wiring and connections
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.