Viessmann VITODENS 111-W Installation And Service Instructions Manual page 59

Functions and operating conditions in...
DHW heating
Heating the DHW primary store from
cold
The heating circulation pump is switched
on and the 3-way diverter valve will be
changed over if the cylinder temperature
sensor captures a temperature lower
than the defaulted set value.
■ The cylinder primary pump is switched
on if the boiler water temperature ≥ set
DHW temperature.
■ The burner is switched on if the boiler
water temperature ≤ set DHW temper-
ature, and the cylinder primary pump
is switched on when the required boiler
water temperature is reached.
The primary store is heated up to the set
DHW temperature. Heating stops when
the specified temperature has been
reached at the cylinder temperature sen-
sor.
After heating, the cylinder primary pump
and the 3-way diverter valve remain on
for a further 30 s.
Reheating when DHW is drawn off
When DHW is drawn off, cold water
enters at the bottom of the primary
store.
The heating circulation pump is switched
on and the 3-way diverter valve is
changed over if the cylinder temperature
sensor recognises a temperature lower
than the set value.
(cont.)
■ The cylinder primary pump is switched
on if the boiler water temperature ≥ set
DHW temperature.
■ The burner is switched on if the boiler
water temperature ≤ set DHW temper-
ature, and the cylinder primary pump
is switched on when the required boiler
water temperature is reached.
DHW is regulated to the set temperature
via the outlet temperature sensor.
The primary store continues to be heated
up after the draw-off process has termi-
nated until the set DHW temperature has
been reached at the cylinder tempera-
ture sensor.
The cylinder primary pump and the 3-
way diverter valve remain on for a further
30 s.
Control unit
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