Ariston NIMBUS PLUS S NET Manual page 89

MAINTENANCE
Maintenance is an essential operation to insure safety, correct
working and duration of life of the appliance.
It must be carried out in accordance with the regulations in force.
It is requested to check periodically the pressure of the refrigerant
gas. Before proceeding with maintenance:
• Disconnect the power supply from the appliance
• Close the water taps of the heating circuit
IMPORTANT!
The minimum temperature value of the water in heating, for a cor-
rect functioning of the system, is 20 ° C. During the starting phase
of the machine, it is allowed to work with lower temperatures. If
the external temperature reaches a value below 12 ° C it is ne-
cessary to have a backup energy source. NEVER DISCONNECT
THE INTEGRATED RESISTIVE ELEMENTS FROM THE TERMINAL
BOARD
General remarks
It is necessary to perform at least once a year the following checks:
1. Visual control of the general state of the system.
2. Check for leakage of the hydraulic circuit and possible replace-
ment of the seals.
3. Tightness of the circuit of the refrigerant gas.
4. Check the functioning of the heating safety tools (thermostats).
5. Overall control of the functioning of the appliance.
6. Check the pressure on the heating circuit.
7. Check the pressure of the expansion vessel
8. Keep clean the front grille and the outdoor unit battery pack.
ATTENTION
Empty the components that may contain residual hot water befo-
re manipulating them.
Remove limestone deposits from the components, following the
instructions on the descaling agent used.
Do this in a ventilated room, wearing the necessary safety devices,
avoid mixing of chemical products and protecting the equipment
and surrounding objects.
Information for the user
Inform the user on how the installed appliances work.
In particular, provide the user with the instruction manual, infor-
ming him of the need to keep the booklet close to the appliance.
Also, inform the user of the need to proceed with the following
actions:
• Periodically check the water pressure
• Pressurize the system, when necessary providing an adequate
air purge
• Adjust the parameters setting and devices in order to obtain a
better functioning and a more economical management of the
system
• Subcontract, as provided by the rules, periodic maintenance
Antifreeze function of the external unit
The main circulator of the internal unit starts at the minimum
speed when leaving water temperature (LWT) sensor is
below 10°C in heating mode or below 1°C in cooling mode.
The main circulator stops when the leaving water
temperature (LWT) sensor is above 10°C in heating mode
or above 4°C in cooling mode.
In case of failure of LWT sensor the protection logics is
based on the outdoor temperature sensor (OAT) of the
external unit.
The main circulator starts when the outdoor temperature
sensor is lower 7°C in heating mode.
The main circulator stops after 30" or when the outdoor
temperature sensor is above 8°C in heating mode.
This check is repeated every 15 min.
Antifreeze function of the internal unit
The main circulator of the internal unit starts at the maximum
speed when the measured temperature by the CH Flow
temperature sensor is below 7°C in heating mode.
If the temperature is still below 9°C after 5 minutes, then the
HP Compressor start at 50% frequency. If the temperature
is still below 9°C after 25 minutes, the resistance is turned
on.
The main circulator stops when the CH Flow temperature
sensor is above 9°C in heating mode.
89 / GB