Viessmann Vitodens 111-W Error 77: Burner in a fault state

Viessmann Vitodens 111-W water heater · taken from the manufacturer’s manual, pages cited

Fault code77

Fault 77 indicates the burner is in a fault state due to an error in HBMU heat management unit data memory. The manual's first action is: “Reset the appliance. If the fault occurs repeatedly, replace the HBMU heat management unit. See chapter "Replacing the HBMU heat management unit".”

Model
Viessmann Vitodens 111-W
Display shows
Burner in a fault state (77)
Type
Fault code
Source
Manual p. 71

What 77 means

Burner in a fault state p. 71

Common causes

  • HBMU heat management unit data memory p. 71

What to do

  1. Reset the appliance. If the fault occurs repeatedly, replace the HBMU heat management unit. See chapter "Replacing the HBMU heat management unit". p. 71

If 77 is still not resolved

The manual gives no further instruction for this code. Open the code table in the PDF or contact Viessmann service.

Open the manual at page 71 All Vitodens 111-W error codes Manual details & download

This page summarises what the manufacturer’s manual says about 77; each statement links to the page it comes from, and quoted lines are copied word for word. It is not a substitute for the manual or for a qualified installer. ManualLib is not affiliated with Viessmann. Found a mistake? Report an error.