General Information On The Electrical Connection; Installation - Viessmann Vitocal 350-G Installation And Service Instructions Manual

Product information
Type BWS 351.A18 (heat pump stage 2)
The heat pump stage 2 has a separate
refrigerant circuit with EEV controller, but
no separate heat pump control unit.
Stage 2 is switched via the heat pump
control unit of stage 1.
Depending on the hydraulic connection,
the 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 required for the heat
pump stage 2.

General information on the electrical connection

■ Connecting cables, heat pump
stage 1 – stage 2:
See page 68.
■ Electrical connection of system
components (pumps, mixers, valves,
alarm facilities, contactors, function
extensions, sensors etc.):
These connections are made inside
the heat pump control unit. Observe
information from page 69.
■ Power supply:
The number of power cables from the
distribution board (meter box) to the
heat pump control unit depends on the
system version and tariffs used, see
information from page 91.

Installation

For handling purposes, the heat pump
module can be removed (see
page 122).
(cont.)
With the 2-stage version, either a sepa-
rate primary pump can be used for both
stages, or a common primary pump can
be used on the primary side. Irrespective
of this, the flow and return temperature
sensors are installed in the primary cir-
cuit at the common flow and return.
Heat pump stage 2 must be installed to
the left of the heat pump stage 1.
The hydraulic connection is made on-
site.
!
Preparing for installation
Please note
Prevent damage to the appliance
during handling.
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