Viessmann Vitoligno 300-C Installation And Service Instructions Manual page 157

Control functions
(cont.)
Boiler control sequence (with heating water buffer
cylinder)
■ Start
The boiler starts if the "Set system temperature
the selected buffer temperature sensor ("Boiler start
sensor", coding address 39) is undershot.
■ Control mode
The boiler combustion output is reduced if the
"Actual buffer temperature
ture *11 " .
■ Shutdown
The boiler heats the heating water buffer cylinder
until the selected temperature ("Buffer cylinder
charging up to temperature", code 37) at the selec-
ted buffer temperature sensor ("Buffer cylinder
charging up to sensor", code 36) is reached.
Solar circuit control
The solar circuit pump is controlled via the differential
temperature between the solar circuit and DHW heat-
ing (code 6E). If the differential temperature between
the collector and the DHW is above the set value, the
solar thermal system activates the pump and mixer for
heating DHW. The actual collector temperature must
be sufficient.
Heating circuit control unit
The heating circuit flow temperature is captured by the
flow temperature sensor.
The flow temperature is regulated by the stepped
opening or closing of the mixers.
The mixer motor control changes the actuating and
pause times subject to the control differential (control
deviation).
Coding addresses
Coding addresses that influence heating circuit con-
■
trol:
A0 to FB
For a description, see the relevant coding address in
chapter "Codes".
The set flow temperature of each heating circuit is
determined from the following parameters:
■ Operating mode
■ Heating curve slope and level
■ Time program
■ Outside temperature
■ Set room temperature
Operating modes
■ Operation with standard room temperature
■ Operation with reduced room temperature
Set system temperature = highest temperature demanded by all control circuits (heating circuits, DHW heating)
*13
Actual buffer temperature = actual temperature value (currently present temperature) of the heating water buffer cylinder
*12
Set buffer temperature = set temperature for the heating water buffer cylinder
*11
" at
*13
" "Set buffer tempera-
*12 ≥
DHW is heated until the following conditions are met:
■ Maximum DHW temperature (code 6F) is reached.
Or
Differential temperature between solar thermal sys-
■
tem and DHW heating (code 6E) is less than the set
value.
■ Party mode
Party mode allows the user to operate the heating
irrespective of the operating mode, and outside of
the enable times specified by the time switch.
This function can be activated from within any oper-
ating mode.
When selecting party mode, the temperature level
must be set.
The function is started as follows:
Activation via menu
–
The function is terminated as follows:
– Automatically when the specified time (CA:F2)
expires
– Deactivation via menu
– Activation of the economy function
When the time switch changes from "Off" to "On"
–
(irrespective of the set operating mode)
■ Holiday program
When the holiday program is activated, the heating
output is regulated to the reduced set room tempera-
ture. On the days of departure and return, the
"standard" time program remains active.
Function description
157