Cylinder Temperature Control - Viessmann Vitotwin 300-W Installation And Service Instructions For Contractors

Function description
Boiler temperature control
The Vitotwin 300-W auxiliary burner
remains blocked as long as there is an
adequate flow temperature from the
solid fuel boiler.

Cylinder temperature control

DHW heating begins when the cylinder
temperature is 2 K below the set cylinder
temperature and ends when the set cyl-
inder temperature is reached.
Both burners start with a time delay in the
delivered condition.
The enable criteria for both burners can
be changed via code 3213 to optimise
burner runtimes.
Setting options:
■ "No restrictions"
Same enable criteria as for central
heating.
■ "Eng bu only"
Only the Stirling burner is enabled for
DHW heating. The auxiliary burner is
only enabled in the event of a Stirling
burner fault.
156
(cont.)
■ "First charg eng bu only"
Only the Stirling burner is enabled for
the first DHW heating operation of the
day. The auxiliary burner is only ena-
bled in the event of a Stirling burner
fault.
Enable is unrestricted for any other
DHW heating operations during the
day.
■ "Fir'cha. eng bu, supp bu else"
Only the Stirling burner is enabled for
the first DHW heating operation of the
day. The auxiliary burner is only ena-
bled in the event of a Stirling burner
fault.
Only the auxiliary burner is enabled for
any other DHW heating operation dur-
ing the day (unless the Stirling burner
is already in operation).