F.49
FAULT CODE
Vaillant
eBUS Communication Error
Medium Severity
Engineer Required
There is a communication fault on the eBUS — the data bus that allows the boiler and connected controls (like a Vaillant VRT thermostat) to communicate.
Step-by-Step Fix Guide
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Step 1
Check that all wiring connections between the boiler and thermostat/controls are secure
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Step 2
Try turning the boiler off at the mains for 10 minutes, then restart
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Step 3 Engineer only
If the fault persists, a Gas Safe engineer should check for a short circuit on the eBUS wiring
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.