Viessmann Vitocal 222-S Installation And Service Instructions For Contractors page 49

Electrical connection
Fig. 46
Power supply
Isolators for non-earthed conductors
■ Install an isolator in the power cable to provide
omnipolar separation from the mains for all active
conductors, corresponding to overvoltage category
III (3 mm) for full isolation. This isolator must be fitted
in the permanent electrical installation in line with
installation requirements, e.g. mains isolator or
upstream circuit breaker.
■ We additionally recommend installing an AC/DC-
sensitive RCD (RCD class B
currents that can occur with energy efficient equip-
ment.
■ Residual current devices to DIN VDE 0100-530
selecting and sizing.
Danger
Incorrect electrical installations can lead to seri-
ous injury from electrical current and result in
appliance damage.
Connect the power supply and implement all
safety measures (e.g. RCD circuit) in accord-
ance with the following regulations:
IEC 60364-4-41
■
VDE regulations
■
■ Technical connection requirements specified
by the local power supply utility
(cont.)
GND Rx/Tx- Rx/Tx+
Modbus
) for DC (fault)
Danger
The absence of system component earthing can
lead to serious injury from electrical current and
component damage in the event of an electrical
fault.
The appliance and pipework must be connected
to the equipotential bonding of the building.
Danger
Incorrect core assignment can lead to serious
injury from electrical current and result in appli-
ance damage.
Never interchange cores "L" and "N".
■ In negotiations with your power supply utility, differ-
ent supply tariffs for the main power circuits may be
offered.
Observe the technical connection conditions of the
power supply utility.
■ If the compressor and/or instantaneous heating
water heater are operated at an economy tariff
(power-OFF), either provide an additional cable (e.g.
3 x 1.5 mm 2 ) for the power-OFF signal from the dis-
tribution board (meter box) to the heat pump control
unit.
or
Combine the cables for the power-OFF signal and
for the heat pump control unit power supply
(3 x 1.5 mm 2 ) in a 5-core cable.
Installation sequence
230 V/
50 Hz
49