Overview Of Buffer Cylinders - Viessmann VITOTRONIC 200 Service Instructions Manual

Function description
Buffer cylinder
(cont.)
Functions
■ For bridging power-OFF periods:
The buffer cylinder supplies the heating/cooling cir-
cuits including during this power-OFF time.
For the hydraulic separation of the secondary circuits
■
and the heating/cooling circuits: For example, if the
flow rate in the heating/cooling circuits is reduced by
thermostatic valves, the flow rate in the secondary
circuit remains constant.
■ Longer heat pump operating times
The greater water volume and possible separate shut-
ting-off of the heat generator make the provision of an
additional or larger expansion vessel necessary.

Overview of buffer cylinders

A distinction is made between heating water buffer cyl-
inders and heating water/coolant buffer cylinders in
terms of equipment and function.
Equipment/function
Hydraulic connection to the sys-
tem
Central heating
Central cooling
Enable with "Enable buffer cyl-
inder/low loss header 7200"
Number of heating circuits
Number of cooling circuits
Separate cooling circuit
Parameter for central cooling
Cooling functions
Changeover between heating
and cooling mode
Buffer temperature sensor
44
Protect the heat pump in accordance with EN 12828.
Note
For heating or cooling of the buffer cylinder and the
heating/cooling circuits connected to it, the flow rate on
the secondary side must be split inside the buffer cylin-
der. The secondary pump flow rate must therefore be
greater than the total flow rate of all heating circuit
pumps.
Heating water buffer cylinder
Parallel in secondary circuit flow
X
Heating water buffer cylinder is by-
passed in cooling mode by means of
the hydraulic bypass circuit.
"1" Only central heating
Max. 3
Max. 1
X
Only "71xx"
Natural cooling, active cooling
Automatic, as in cooling mode, the
heating water buffer cylinder is by-
passed by means of the hydraulic by-
pass circuit.
Installed at top, connection to F4 on
controller and sensor PCB
Heating water/coolant buffer cylin-
der
Parallel in secondary circuit flow
X
X
"1" Only central heating
"2" Central heating and central cool-
ing
Max. 3
Max. 3
—
"Cooling function 7100"
A1/HC1 "20xx"
M2/HC2 "30xx"
M3/HC3 "40xx"
Active cooling
Manual with "Buffer cyl operating
mode 721F"
Installed at top, connection to F4 on
controller and sensor PCB