Heat Pump Cascade: 2-Stage (Type Bw 302.D090 To Bw 302.D230) - Viessmann Vitocal 300-G Pro Series Installation And Service Instructions For Contractors

Hydraulic connection requirements

Heat pump cascade: 2-stage (type BW 302.D090 to BW 302.D230)

A heat pump cascade consists of a lead heat pump
and lag heat pumps.
Each lag heat pump has a heat pump control unit.
Both the lead and lag heat pumps can have 2 stages.
The lead heat pump regulates the operation of the
heat pumps within the cascade.
Hydraulic installation scheme
IV
Fig. 13
Interface to heating water buffer cylinder
A
(return)
Interface to the separate cooling circuit or heat-
C
ing/cooling circuit
Interface to heating water buffer cylinder (flow)
H
Interface to primary circuit (flow)
P
Equipment required
Pos. Description
Heat generator
Heat pumps
1
Heat pump control unit
2
Outside temperature sensor
3
LON communication module for cascade control of the lead heat pump I
4
LON communication module for lag heat pumps II to IV
Secondary pump 1 (fail-safe)
5
Circulation pump for cylinder heating (fail-safe)
6
(cont.)
Up to 4 lag heat pumps possible when connected via
■
LON.
The following communication modules (accessories)
must be fitted in the heat pump control units:
– LON cascade communication module in the lead
heat pump
LON communication module in lag heat pumps
–
III II
Interface to primary circuit (return)
Q
Interface to the DHW cylinder
W
I Lead heat pump in the heat pump cascade
(1-stage or 2-stage)
II to IV Lag heat pump in the heat pump cascade
(1-stage or 2-stage respectively)
Preparing for installation
I
19