Technical Service Bulletin
Issue: Burner is locked out with fault code F6
Applies to: Vitocrossal 300, CU3A Series (all models)
The information in this bulletin is intended exclusively for licensed heating contractors, and is NOT intended for the end user. This material is NOT intended to take the place of the information contained in the manuals shipped with the product.
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The burner is locked out, and fault code "F6" is displayed on the boiler control.
Faulty boiler water temperature sensor.
Test and replace the boiler water temperature sensor according to the Service Instructions for Vitocrossal 300, CU3A.
The F6 fault code indicates that the temperature values of the dual-element boiler water temperature sensor vary too widely from each other.
This fault code does not appear in the Service Instructions as of this date; updates will be included in the next edition.