Viessmann VITOCAL 300-G PRO Installation And Service Instructions Manual page 36

Preparing for installation
Heat pump cascade: 1-stage/2-stage
■ Up to 3 lag heat pumps, subject to
connection via KM BUS, in conjunction
with the external H1 extension (see
page 70 and separate service
instructions for Vitotronic 200 heat
pump control unit).
■ Up to 4 lag heat pumps, subject to
connection via LON (see separate
service instructions for the Vitotronic
200 heat pump control unit).
36
(cont.)
The following communication modules
(accessories) must be fitted in the heat
pump control units:
– LON cascade communication mod-
ule in the lead heat pump
– LON communication module in lag
heat pumps