Viessmann VITOCAL 300-G Installation And Service Instructions Manual page 95

Electrical connections
Required parameters:
Parameter Ó setting
"Electric heater"
■ "Inst. heating water heater 7900" Ó "1"
■ If necessary "Heating with electro 7902" Ó "1"
Power-OFF
The supply voltage to the relevant components (subject to power supply utility) is
switched off by the power-OFF contact signal.
X3.7
A
B
X3.6
A Terminals on cross connect PCB
B Zero volt N/C contact
Breaking capacity 230 V~, 0.15 A;
remove jumper when making this
connection
Contact open:
Contact closed:
External heat source
■ For PCB locations (terminal and plug
markings), see from page 75.
■ For examples of connecting pumps
and mixers, see system examples
from page 44.
■ For connections of all pumps and mix-
ers to main PCB with extension, see
page 221.
For connection of all ? and N cables
to cross connect PCB, see page 225
(cont.)
Power-OFF ena-
bled
Power-OFF disa-
bled
Installation sequence
Note
■ No parameters need to be set.
■ The compressor is forced OFF as
soon as the contact opens.
■ For the instantaneous heating water
heater, the stages to be switched off
can be selected. See parameter
"Stage at power-OFF 790A" on
page 197.
For further information, see from
page 103.
■ For all sensor connections to the con-
troller and sensor PCB, see
page 228.
■ For parameter settings, see from
page 171.
95