Buffer Cylinder In Conjunction With Heat Pump Cascade - Viessmann VITOTRONIC 200 Service Instructions Manual

Buffer cylinder
(cont.)

Buffer cylinder in conjunction with heat pump cascade

To ensure stratification in the upper section of the buf-
fer cylinder in heating mode, allocate the buffer cylin-
der connections as follows:
Connect the secondary flow from the heat pump cas-
■
cade to one of the centre connectors of the buffer
cylinder.
■ Connect the heating/cooling circuit flow to the top
connector of the buffer cylinder.
Heating the buffer cylinder with the heat pump
Applicable to:
Heating water buffer cylinder
■
■ Central heating with heating water/coolant buffer cyl-
inder
Switching heat-up on and off
If the buffer temperature falls below the current set buf-
fer temperature by more than "Hysteresis tempera-
ture heating buffer cylinder 7203", heating of the
buffer cylinder is activated. The current set buffer tem-
perature is always the highest set flow temperature of
all connected heating circuits.
Operating status in time
program for buffer cylinder
"Top"
"Standard"
"Fixd value"
Note
The operating status "Fixd value" can be blocked for
the buffer cylinder if there is no heat demand from any
of the connected heating circuits ("Operating mode,
fixed value only for heat demand 720A" set to "1").
In such cases, the buffer cylinder is only heated to the
set temperature for operating status "Standard".
Buffer cylinder heating
ON
Set buffer temperature less
"Hysteresis temperature
heating buffer cylinder
7203" at buffer temperature
sensor is undershot.
/
Heating is deactivated if the temperature at the stop
temperature sensors rises above the stop temperature
or as soon as "Max. temperature buffer cylinder
7204" is reached.
Note
In the event of a fault in the buffer temperature sensor,
heating of the buffer cylinder is stopped immediately.
OFF
Set buffer temperature plus "Stop hysteresis,
■
buffer cylinder 7209" at buffer temperature
sensor is exceeded.
If no buffer temperature sensor is installed, the
■
secondary circuit return temperature sensor is
used.
Set buffer temperature at buffer temperature
■
sensor is exceeded.
and
Set buffer temperature plus "Stop hysteresis,
■
buffer cylinder 7209" at secondary circuit re-
turn temperature sensor is exceeded.
"Temp in operating status fixed value for buf-
■
fer cyl 7202" at buffer temperature sensor is ex-
ceeded.
and
"Temp in operating status fixed value for buf-
■
fer cyl 7202" plus "Stop hysteresis, buffer
cylinder 7209" at secondary circuit return tem-
perature sensor is exceeded.
Operating status
"Vitotronic 200" operating instructions
Function description
45