Viessmann Vitocal 300-G Installation And Service Instructions Manual page 84

Installation sequence
Connection of electrical components
A Terminals on PCB 1
B Zero volt N/C contact
Note
Generally, the compressor is switched
mechanically, as soon as the contact
opens. For the instantaneous heating
water heater, the stages to be
switched off can be selected (see
parameter 790A on page 158).
Cascade control (lead appliance)
Note
Terminals of the "External
extension H1" (see Fig. on page 86)
Open contact 1X3.10/1X3.11 trig-
gers a fault message (see central
fault message, page 87).
Equipment
Cascade control See Fig. on
(lead appliance) page 86.
84
For further information, see the follow-
ing chapter:
Power connection from page 92.
Power connection, compressor,
page 96.
Contact open:
Contact closed:
Connection Comments
ID
The connection on the second, third
and fourth heat pump is made using
the zero volt contact at the "Ext. de-
mand" terminal.
700A Cascade control
7010 External extension
700B Output, lag heat pump
5735 No. of external heat pumps
(cont.)
Block enabled
Block disabled
Setting parameters (group)
Ó 1 (system definition)
Ó Yes (system definition)
Ó Enter output value (system
definition)
Ó 1 to 3 (system definition)