Viessmann VITOTRONIC 200 Service Instructions Manual page 15

Heat pump cascade
Cascade via LON
The following communication modules
(accessories) must be fitted in the heat
pump control units:
■ LON communication module for the
cascade in the lead appliance
■ LON communication module in lag
heat pumps
Subject to the system equipment level,
all heat pumps within a LON cascade
can be enabled separately for different
functions by means of parameter "Use
of heat pumps in cascade 700C":
■ Central heating/cooling
■ DHW heating
■ Swimming pool heating
■ Solar DHW heating
(only possible in conjunction with inte-
gral solar control function)
Several functions can be active simulta-
neously.
Central heating/cooling
Lead appliance and lag heat pumps are
connected hydraulically in parallel, with
each branch having its own circulation
pump.
Integrating a heat pump control unit into LON
Example of a heat pump cascade and Vitocom
A
A Heat pump control unit lead appli-
ance
(cont.)
DHW heating
Connection versions for lead appliance
and lag heat pumps:
■ Parallel to the flow to the DHW cylin-
der:
Each lag heat pump has its own circu-
lation pump for cylinder heating, which
is switched on by the lag heat pump
when there is a demand from the lead
appliance.
■ Via the 3-way diverter valve for "cen-
tral heating/DHW heating" in each
pump, parallel to the flow to the DHW
cylinder:
The changeover takes place subject to
the demand from the lead appliance to
the lag heat pump in question.
■ Parallel to a common flow secondary
circuit:
The changeover is carried out by a
central 3-way diverter valve for "cen-
tral heating/DHW heating". This is
controlled via the heat pump control
unit of the lead appliance.
B
B Heat pump control unit lag heat
Function description
C
pump
15