Ariston NIMBUS EXTERNAL UNIT 04 Technical Instructions For Installation And Maintenance page 56

Electrical connections of the internal unit
Before any operation on the system, turn off the main power.
Observe the phase and neutral connections.
To access the control panel of the internal unit, proceed as follows:
Remove the three screws indicated in fi gure (A) and remove the cover
of the electrical panel (B).
Opening of the internal unit you will fi nd the following connections:
RS 485 - Communication with the external unit. Observe the polarities.
The marking «1» on the terminal block refers to connection
«1» on the heat pump,
«2» refers to connection «2» on the heat pump.
ANODE - Boiler Protech anode connection (NIMBUS FLEX).
Observe the electrical polarities.
TA1 - Ambient contact thermostat connection, zone 1.
TA2 - Ambient contact thermostat connection, zone 2.
SE - External temperature sensor connection.
TNK - Boiler sensor connection (NIMBUS FLEX).
BUS - Sensys connection.
IN-AUX - Humidistat/auxiliary input connection
PV - Photovoltaic input connection
EDF - 230V input for HC-HP domestic water function
if provided by electrical utility.
See par. 17.5.3.
DLST - 230V input for deactivating the
supplementary heating elements in case of partialisation of
electric loads,
if provided by electrical utility. See par. 17.2.2.
OUT-AUX- Auxiliary output
ST1 - Safety thermostat connection (230 V)
for under-fl oor system (shunt connection).
PM AUX- Auxiliary pump connection.
V1 - Diverter valve connection for domestic water circuit
(NIMBUS FLEX).
V COOL- Diverter valve connection for cooling circuit
L - Power phase connection (230 V)
for internal unit
N - Power neutral connection (230 V)
for internal unit
- Earth connection for internal unit.
The size and length of the cables must be sized according to the
power indicated on the data plate of the internal unit.
Ensure that the power cables are properly tightened in order to avoid
overheating.
In case of an installation of an NIMBUS MGP 2 Zone with two under-
fl oor systems, the safety thermostat of the heating zone 1 should
be connected to the terminal at the positions indicated by ST1. The
thermostat of the heating zone 2 should instead be connected to the
connector ST2 on Zone manager pcb (refer to the wiring diagram of
the system
WARNING
After making the connections between the indoor and outdoor
units, replace both panels of the respective panels.
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A
B