Viessmann VITOLIGNO 300-P Service Instructions Manual page 26

Commissioning, inspection, maintenance
Further details regarding the individual steps
System version 3 — Vitoligno 300-P with one or two heating circuits with mixer,
solar buffer cylinder (for solar central heating backup) and DHW cylinder
(optional with dual mode DHW cylinder and solar thermal system with Vitosolic
200)
Function description
The heating circuits eP and rP are regu-
lated by control unit Vitotronic 200, type
FO1 2 of the Vitoligno 300-P 1. The
boiler will only start if there is a demand
for the DHW cylinder or a heating circuit.
The time program for heating mode and
heating up the DHW cylinder qP is set at
the boiler control unit.
Heating up the solar buffer cylinder
and raising the return temperature
The boiler and boiler circuit pump 5
start when the actual temperature at buf-
fer temperature sensor tQ falls below
the set temperature for heating circuits
eP and rP, or DHW cylinder qP. The
boiler shuts down and the boiler circuit
pump runs on for approx. 10 min when
the actual temperature at buffer temper-
ature sensor tW falls below the set tem-
perature for the heating circuits. Mixing
valve 4 in the return temperature rais-
ing facility holds the boiler return water at
a minimum of 45 °C. Set the water cir-
culation volume in the boiler circuit of the
Vitoligno 300-P so that a temperature
spread of 15 K between the boiler flow
and return results at the rated boiler
heating output.
26
(cont.)
DHW heating by the Vitoligno 300-P
The DHW is heated up if the actual tem-
perature falls below the set DHW tem-
perature at cylinder temperature sensor
qQ, subject to cylinder heating being
enabled by the time program. The boiler
water temperature is regulated to the set
cylinder temperature + 15 K or the mini-
mum boiler water temperature of 60 °C.
Circulation pump for cylinder heating
qE starts when the heating water buffer
cylinder temperature (top) lies 7 K above
the cylinder temperature.
If the heating circuits are regulated via
the Vitotronic 200, type FO1 2, heating
circuit pumps M1 eE and M2 rE stop,
and mixers M1 eR and M2 rR are
closed, subject to absolute priority being
enabled (recommended).
With modulating priority, heating circuit
pumps M1 eW and M2 rE remain
switched on, and mixers M1 eE and M2
rR are closed far enough for the set
boiler water temperature required for cyl-
inder heating to be achieved. DHW cyl-
inder qP and heating circuits eP and
rP will then be heated simultaneously.
Heating mode
In accordance with the control unit used,
the flow temperature of heating circuits
eP and rP is modulated subject to the
outside temperature. The boiler water
temperature is regulated 8 K higher than
the set flow temperature or the minimum
boiler water temperature of 60 °C.