Information
Product information
Note
Heat pump stage 2 must be installed to the left of heat
pump stage 1.
Design
Heat pump stage 2 has a separate refrigerant circuit
with refrigerant circuit controller, but no separate heat
pump control unit. Stage 2 is switched via the heat
pump control unit of stage 1.
System examples
Available system examples: See www.viessmann-
schemes.com.
8
(cont.)
Hydraulics
On the primary side of a 2-stage version, either use a
separate primary pump for each stage, or use a
shared primary pump. Irrespective of this, the flow and
return temperature sensors are installed in the primary
circuit on the shared flow and return.
Depending on the hydraulic connection, heat pump
stage 2 can be used both for central heating and for
DHW heating. A separate secondary pump and circu-
lation pump for cylinder heating (both accessories) are
therefore required for the heat pump stage 2.